back to indexWhat Alcohol Does to Your Body, Brain & Health | Huberman Lab Podcast #86
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Welcome to the Huberman Lab Podcast,
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where we discuss science and science-based tools
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for everyday life.
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I'm Andrew Huberman,
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and I'm a professor of neurobiology and ophthalmology
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at Stanford School of Medicine.
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Today, we're discussing alcohol,
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one of the most commonly consumed substances
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on the planet Earth.
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I should mention that both humans and non-human animals
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consume alcohol either for recreational purposes
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because they like the feeling that it gives them
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or for medicinal purposes
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or for other purposes that we'll discuss.
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We are, of course, going to discuss the effects of alcohol
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ranging from its effects on individual cells,
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on organs and organ systems in our brain and body.
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We are also going to discuss the effects
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of the effects of alcohol.
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That is what being inebriated really does
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to our thinking and our behavior and how it does it.
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And we are going to address what seems to be
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one of the more common questions out there,
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which is whether or not low to moderate amounts of drinking
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are better for our health
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than zero alcohol consumption at all.
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And of course, we will talk about severe alcohol intake,
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We will also talk about hangover
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and what science says about ways
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to reduce the effects of hangover,
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either by doing things that are inoculatory,
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meaning before you drink or while you drink,
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as well as things to do if you happen to have a hangover.
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We will discuss some of the genetic differences
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for alcohol and alcoholism,
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and we will discuss alcohol consumption in young people
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and how that can be especially detrimental
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for reasons that I think are going to be quite surprising
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My goal is that by the end of today's episode,
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you will have a thorough understanding
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of what alcohol does to your brain and body,
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and that you will be able to make informed decisions
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as to whether or not you should be consuming
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zero, absolutely no alcohol,
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small to moderate amounts of alcohol.
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And again, we'll define exactly what that means,
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small to moderate amounts.
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And if you or somebody else that you know
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is consuming excessive amounts of alcohol
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that are clearly detrimental to your health,
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some of the better routes and resources that you can use
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in order to remove that dependence and or consumption.
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I'd like to preface all of that by saying that
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today's discussion is really geared
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toward giving you information.
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It is not about judging alcohol intake
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or lack of alcohol intake.
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I just want you to be able to make
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the most informed decision about alcohol possible.
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I'm pleased to announce that the Huberman Lab Podcast
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is now partnered with Momentus Supplements.
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We partnered with Momentus for several important reasons.
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First of all, they ship internationally
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because we know that many of you are located
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outside of the United States.
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Second of all, and perhaps most important,
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the quality of their supplements is second to none,
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both in terms of purity and precision
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of the amounts of the ingredients.
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Third, we've really emphasized supplements
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that are single ingredient supplements
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and that are supplied in dosages that allow you
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to build a supplementation protocol
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that's optimized for cost,
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that's optimized for effectiveness,
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and that you can add things and remove things
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from your protocol in a way that's really systematic
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If you'd like to see the supplements
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that we partner with Momentus on,
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you can go to livemomentus.com slash Huberman.
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There you'll see those supplements
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and just keep in mind that we are constantly expanding
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the library of supplements available through Momentus
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on a regular basis.
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Again, that's livemomentus.com slash Huberman.
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Before we get into today's content in detail,
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I just want to answer a commonly asked question
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about alcohol consumption and the brain.
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And the question that so often comes up
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is whether or not low to moderate amounts of alcohol,
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so maybe one drink a day or one or two drinks a day
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kind of thing, whether or not that is bad for your brain,
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in particular, whether or not it causes degeneration
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of neurons or nerve cells.
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Now, the reason that question comes up so often
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is because for many years it's been known
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that high levels of alcohol consumption,
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so 12 to 24 drinks per week or more,
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is certainly causing neurodegeneration,
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in particular of the so-called neocortex,
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the outer layers of the brain
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that house associative memories,
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that house our ability to think and plan,
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that house our ability to regulate our more primitive drives
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according to context, et cetera.
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So to make very clear, drinking a lot,
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so having three or four drinks per night
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every night of the week is clearly bad for the brain.
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A recent study, however, finally addressed the question
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of whether or not low to moderate amounts
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of alcohol consumption can cause brain degeneration.
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The title of the study is
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Associations Between Alcohol Consumption
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and Gray and White Matter Volumes in the UK Biobank,
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the United Kingdom Biobank.
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First of all, gray matter are the neurons,
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it's the so-called cell bodies
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that house the genome of the cells, et cetera,
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and white matter is the connections, the fibers,
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the so-called axons of neurons,
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and it's called white matter
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because that tissue is surrounded
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by a fatty tissue called myelin,
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which allows nerve cells
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to communicate with each other very quickly.
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So what this study did is it looked at the brains,
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both the gray matter and the white matter,
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of more than 30,000, indeed more than 35,000
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generally healthy middle-aged and older adults
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in the United Kingdom
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who were drinking various amounts of alcohol.
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What they found was that even for people
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that were drinking low to moderate amounts of alcohol,
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so one or two drinks per day,
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there was evidence of thinning of the neocortex,
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so loss of neurons in the neocortex and other brain regions.
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And I don't say this in order to cause alarm.
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I tell you this because they are important data
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because they reveal and indeed answer the question
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that has been burning for so long
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as to whether or not chronic alcohol intake
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can disrupt the brain,
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even if the chronic intake is very low.
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Now, we should talk about what the word chronic means
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because many people, when they hear the word chronic,
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think high levels of whatever intake, okay?
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So they think five drinks a night or 10 drinks a night
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or people drinking every night.
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Now, in this study, they looked at people who on average
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were drinking one or two drinks per night.
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So that could be 14 drinks on the weekend.
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It could be one drink per night.
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It could be seven drinks on Friday.
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In other words, on average, one or two drinks per night.
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And I think many people out there are drinking
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somewhere between one and two drinks per night
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or day of the week on average.
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So that would be seven to 14 drinks per week.
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So this is an important study because it says
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that if you're consuming even just seven glasses of wine
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across the week, it's likely that there is going to be
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some degeneration of your brain
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in response to that alcohol intake.
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Although, as mentioned earlier,
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we will talk about some of the things
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that can inoculate against some of that neuronal loss.
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For those of you that are interested in reading the study
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in more detail, we put a link to it
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in the show note captions.
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Before we begin, I'd like to emphasize that this podcast
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is separate from my teaching and research roles at Stanford.
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It is, however, part of my desire and effort
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to bring zero cost to consumer information about science
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and science-related tools to the general public.
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In keeping with that theme,
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I'd like to thank the sponsors of today's podcast.
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Our first sponsor is Levels.
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Levels is a program that lets you see
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how different foods affect your health
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by giving you real-time feedback on your diet
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One of the most important features
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and our ability to focus and think and move and have energy,
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as well as our long-term health,
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are our blood glucose levels.
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That is our blood sugar levels.
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And that's because all the cells and tissues of our body,
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and especially neurons, nerve cells,
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rely on glucose for fuel.
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I realize some of you out there are ketogenic,
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and yes, you can use ketones for fuel,
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but the vast majority of people are using glucose
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for fuel in their cells.
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If you want to maintain energy and focus throughout the day,
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and you don't want it ever to spike or to drop too much.
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go to levels.link slash Huberman.
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Again, that's levels.link slash Huberman.
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Today's episode is also brought to us by Eight Sleep.
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I've talked many times on the podcast about the fact
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And one of the key variables in getting a great night's sleep
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and they also have some unique characteristics.
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Let's talk about alcohol and let's just acknowledge
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that human beings have been consuming alcohol
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for thousands of years.
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If you look at the archeological evidence from Mesopotamia,
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you'll find that 5,000 years ago people had wine vessels
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or if you want to know when people first started
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distilling alcohol, much to people's surprise
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that did not first take place in Ireland
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and that's not a joke about the Irish
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that you'll see a lot of claims online
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that the Irish were the first to distill alcohol
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but in fact they were not.
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It was the Chinese that were the first to distill alcohol
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and that took place in China in the first century.
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Alcohol has been used for nutritional purposes.
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So there are cultures that believe and indeed still believe
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that the calories in alcohol are useful.
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Although later we'll talk about how alcohol calories
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are indeed empty calories and what an empty calorie
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really is, why it's called empty.
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Alcohol has been used for medicinal purposes
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because indeed it does kill bacteria
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and as you'll soon find out the fact that it kills bacteria
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because that is absolutely true,
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it also kills the good bacteria in your gut
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and the destruction of that good bacteria in your gut
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can lead to things like leaky gut syndrome
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and has all sorts of issues
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and there are ways to deal with those issues
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and we'll talk about those.
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So alcohol has been used for medicinal purposes,
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it's been used to clean surfaces,
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it's used in my laboratory in order to make up
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so-called reagents to do our experiments
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but most humans have been consuming alcohol
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in order to change their internal state,
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in order to feel differently than they would otherwise.
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That feeling of being drunk or inebriated
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or tipsy or lightheaded is something that many, not all,
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but many humans seem to enjoy and pursue
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even though typically it leads to a feeling
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of being less happy, less motivated,
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more stressed, et cetera, when the alcohol wears off.
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That's pretty incredible, right?
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I mean, we're talking about a substance
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that people have been highly motivated to pursue
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that are still highly motivated to pursue,
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to create and to consume, that they'll spend money on
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and that's despite the fact that it makes them feel good
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and then it makes them feel lousy.
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Now, some of you might be saying,
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well, I drink but I don't drink to excess
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and therefore I don't feel lousy,
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I feel good when I drink and then it wears off
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and it allows me to get through my evening
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and then the next morning I'm ready to go.
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Okay, that very well may be true, I believe those people
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and as I mentioned at the beginning of the episode,
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I'm not here to demonize alcohol in any way
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but I do want to point out what alcohol is
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and how it creates the effects that it does
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and then I want to talk about what those effects are
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when you engage in consuming alcohol
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even as often as one or two nights per week
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or let's say you're just somebody who has a drink or two
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on Friday, maybe a few more on Saturday
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or maybe you're somebody who consumes all your alcohol
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one night per week or one night per month,
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we'll talk about how that's affecting your biology.
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So let's address what alcohol is
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and how it affects the cells and tissues
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and organs of your body,
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then we'll take a look at some of the epidemiology,
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that is how many people are consuming alcohol
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and how much they're drinking
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and then you will be able I think to get a good sense
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of how the alcohol that you're drinking,
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if you're drinking any at all,
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is impacting your brain and body
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and the choices you might want to make
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about how and when to drink alcohol
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or even if you want to eliminate alcohol altogether.
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Okay, so some basic chemistry and biology of alcohol
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and again, I'll make this very clear
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even if you don't have a chemistry and biology background,
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because of the structure of alcohol,
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it is what's called both water soluble and fat soluble,
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translated into what's meaningful for you,
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what that means is when you drink alcohol,
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it can pass into all the cells and tissues of your body,
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it has no trouble just passing right into those cells,
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so unlike a lot of substances and drugs
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that actually attach to the surface of cells to receptors
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as they're called, little parking spots
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and then trigger a bunch of downstreams
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like domino cascades of effects,
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alcohol actually has its own direct effects on cells
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because it can really just pass into those cells,
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so it's water and fat soluble
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and the fact that it can pass into so many organs and cells
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so easily is really what explains its damaging effects,
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I should mention that there are three main types of alcohol,
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there's isopropyl, methyl and ethyl alcohol
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and only the last one ethyl alcohol or ethanol
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is fit for human consumption, however, it is still toxic,
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okay, it produces substantial stress and damage to cells,
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I'd love to be able to tell you otherwise,
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but that's just a fact,
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ethanol produces substantial damage to cells
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and it does that because when you ingest ethanol,
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it has to be converted into something else
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because it is toxic to the body
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and there's a molecule inside of all of us called NAD
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and you may have heard of NAD because it's quite popular,
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there's a lot of discussion about NAD
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in the longevity literature right now,
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NAD is present in all our cells from birth until death,
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the levels of NAD tend to go down across the lifespan,
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there are ideas that increasing levels of NAD
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may extend lifespan, a lot of that is still controversial
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or at least we should say is ongoing
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in terms of the research,
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but nonetheless, when you ingest ethanol,
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NAD and related biochemical pathways
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are involved in converting that ethanol
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into something called acetaldehyde,
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it's broken down into acetaldehyde
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and if you thought ethanol was bad,
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acetaldehyde is particularly bad,
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acetaldehyde is poison, it will kill cells,
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it damages and kill cells and it is indiscriminate
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as to which cells it damages and kills,
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now that's a problem obviously
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and the body deals with that problem
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by using another component of the NAD biochemical pathway
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to convert acetaldehyde into something called acetate,
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acetate is actually something
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that your body can use as fuel
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and that process of going from ethanol
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to acetaldehyde to acetate
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does involve the production of a toxic molecule, right?
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Again, acetaldehyde is really toxic
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and NAD and if we want to get technical,
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it's the NAD to NADH ratio
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and that chemical step
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is the rate limiting step to ethanol's metabolism,
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what does that mean for you?
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What that means is that if your body
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can't do this conversion of ethanol
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to acetaldehyde to acetate fast enough,
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well, acetaldehyde will build up in your body
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and cause more damage,
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so it's important that your body
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be able to do this conversion very quickly
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and the place where it does that is within the liver
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and cells within the liver
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are very good at this conversion process,
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but they are cells
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and they are exposed to the acetaldehyde
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in the conversion process
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and so cells within the liver really take a beating
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in the alcohol metabolism events,
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so the key thing to understand here
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is that when you ingest alcohol,
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you are, yes, ingesting a poison
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and that poison is converted
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into an even worse poison in your body
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and some percentage of that worst poison
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is converted into a form of calories
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that you can use to generate energy, generate ATP
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and the reason why alcohol is considered empty calories
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is because that entire process is very metabolically costly,
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but there's no real nutritive value
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of the calories that it creates.
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You can use it for immediate energy,
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but it can't be stored
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in any kind of meaningful or beneficial way,
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it doesn't provide any vitamins,
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it doesn't provide any amino acids,
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it doesn't provide any fatty acids,
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it's truly empty calories.
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I know some people talk about sugar as empty calories,
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but sugar actually is a far better fuel source
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than alcohol or acetate,
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but nonetheless, when you ingest alcohol,
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some percentage is being shuttled into a worse poison
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and some is being shuttled into a fuel source.
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Now, the important thing to understand
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is that it is the poison, the acetaldehyde itself,
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that leads to the effect of being inebriated or drunk.
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I think most people don't realize that,
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that being drunk is actually a poison-induced disruption
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in the way that your neural circuits work.
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And so we should ask ourselves,
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which neural circuits, what brain areas,
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what body areas involved in feeling drunk or inebriated?
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Now, when thinking about this state of being tipsy
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or happy or really drunk or a little bit drunk,
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I want to mention something
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I think most people aren't aware of,
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and that's the fact that for people
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that are regular drinkers
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or that have a genetic predisposition to alcoholism,
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when they drink, they tend to feel very energized
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and very good for longer periods of time.
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Again, people have a genetic predisposition to alcohol
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or people who are chronic drinkers,
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or even just, if you recall,
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chronic doesn't have to mean a ton of alcohol,
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but they're drinking one or two per night
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or they're every other night type drinkers
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or Thursday through Sunday drinkers.
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Those people typically experience an increase
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in alertness and mood when they drink,
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whereas occasional drinkers will have a briefer,
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meaning less long lasting,
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period of feeling good when they drink
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and then more quickly transition into a state
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in which they're tired or they start losing motor skills,
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they start slurring their speech.
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I also want to emphasize this is distinct from tolerance.
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We'll talk about tolerance later
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and exactly what tolerance means,
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but I really want to highlight the fact
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that when people ingest this poison,
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because indeed it is poison,
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the range of effects is very different
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and you can reliably predict who are the people
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with a predisposition to alcoholism
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and who are the people who are more regular drinkers
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by the contour, the timing of the different effects.
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And again, people who tend to feel more alert and excited
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every time they drink, they tend to get a real lift.
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They become kind of the life of the party
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and that lasts a long while.
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Those people are the ones that really have to be careful
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about predisposition for alcoholism.
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And those people also need to be careful
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about their drinking and the amount of drinking
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that they're doing, even if they're not full-blown alcoholics
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Now, of course, people who are ingesting alcohol,
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who are not accustomed to drinking alcohol
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have to be concerned about drinking alcohol for other reasons
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because it can impair motor function and judgment, et cetera.
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But in thinking about the biochemical effects of alcohol
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and what it's doing to the body,
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what it's doing in all cases is it's consumed into the gut,
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goes into the stomach.
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The liver immediately starts this conversion
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that we talked about before of ethanol to acetaldehyde
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to acetate and some amount of acetaldehyde and acetate
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are making it into the brain.
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It crosses the blood-brain barrier.
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Again, the brain has this fence around it
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that we call the blood-brain barrier or the BBB.
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Many things, most things thankfully,
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can't pass across the blood-brain barrier,
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but alcohol because it's water and fat soluble
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just cruises right across this fence
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and into the milieu, the environment of the brain,
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which is made up of a couple of different major cell types,
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neurons, nerve cells, and so-called glial cells,
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which are in between the nerve cells.
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And we'll talk about the effects on each of those soon.
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So what happens when alcohol gets into the brain
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that makes us feel tipsy or drunk
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and in some people makes people feel really,
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especially energized and happy?
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Well, alcohol is indiscriminate
link |
in terms of which brain areas it goes to.
link |
Again, it doesn't bind to particular receptors,
link |
but it does seem to have a propensity or an affinity
link |
for particular brain areas that are involved
link |
in certain kinds of thinking and behavior.
link |
So one of the first things that happens
link |
is that there's a slight,
link |
at least after the first drink or second drink,
link |
there's a slight suppression in the activity of neurons
link |
in the prefrontal cortex.
link |
This is an area of your neocortex
link |
that's involved in thinking and planning
link |
and perhaps above all in suppression of impulsive behavior.
link |
So if you go to a party and they're serving alcohol
link |
and people are consuming drinks,
link |
what you'll notice is that a few minutes into that party,
link |
the volume of people's voices will increase.
link |
And that's because people are simply not paying attention
link |
to their voice modulation.
link |
As other people start speaking more loudly,
link |
other people are speaking more loudly.
link |
We've all had this experience, right, of going to a party
link |
and then you step outside for a moment and you go,
link |
oh my goodness, I was shouting.
link |
You come home the next day, you got a sore throat.
link |
It might be that you picked up some sort of bug,
link |
some virus or something.
link |
But oftentimes it's just the fact
link |
you've been shouting all night just to be heard
link |
because as the prefrontal cortex shuts down,
link |
people stop modulating their level of speech quite as much.
link |
Also notice that people start gesticulating more.
link |
People will start standing up and sitting down more.
link |
They'll start walking around more.
link |
If there's music on,
link |
people might spontaneously start dancing.
link |
All of this is because these areas of the prefrontal cortex
link |
normally are providing what's called top-down inhibition.
link |
They are releasing a neurotransmitter called GABA
link |
onto various parts of the brain.
link |
They're involved in impulsive motor behavior
link |
and thought patterns.
link |
And as you shut down the prefrontal cortex,
link |
that GABAergic suppression of impulses starts to be released.
link |
So people will say things that they want to say
link |
without so much forethought about what they're saying.
link |
Or they might do things that they want to do
link |
without really thinking it through quite as much
link |
or they might not even remember thinking it through at all
link |
or experience, I should say, thinking it through at all.
link |
We haven't talked about blacking out yet
link |
in the effects of alcohol on memory.
link |
But as long as we're there,
link |
I'll just tell you that alcohol has a very strong effect
link |
in suppressing the neural networks
link |
that are involved in memory formation and storage.
link |
This is why oftentimes we forget the events of a night out
link |
if we've been drinking.
link |
One of the more important things to know
link |
about the effects of alcohol in the brain
link |
is this disruption in top-down inhibition,
link |
but also that areas of the brain
link |
that are involved in flexible behavior,
link |
sort of considering different options,
link |
like I could do A or I could do B.
link |
I could say this to them or I could say that.
link |
I could say it in that way
link |
or I could say it in this way.
link |
This might be a little more tactful.
link |
Those brain areas basically shut down entirely
link |
and people just tend to say what they want to say.
link |
So the key thing to understand is that when people drink,
link |
the prefrontal cortex and top-down inhibition is diminished.
link |
That is habitual behavior
link |
and impulsive behavior starts to increase.
link |
Now, what's interesting is this is true in the short term,
link |
so after people have one or two,
link |
maybe three or four drinks,
link |
but it's also true that the more often that people drink,
link |
there are changes in the very circuits
link |
that underlie habitual and impulsive behavior.
link |
This is really important to highlight,
link |
so much so that I want to drill into it
link |
a little bit more deeply.
link |
For the person that drinks, say, every Thursday night
link |
or every Friday night
link |
or goes out only on Saturdays, but every Saturday,
link |
there's evidence that there are changes
link |
in the neural circuits of the brain
link |
that control habitual behavior and impulsive behavior,
link |
and they are modified and strengthened
link |
in ways that make those people more habitual
link |
and more impulsive outside the times
link |
in which they are drinking.
link |
And when they drink, impulsive and habitual behavior
link |
tends to increase even further.
link |
This is something that's not often talked about
link |
when discussing the effects of alcohol.
link |
And we all know the effects of being drunk can be bad,
link |
can be bad in terms of judgment, motor coordination,
link |
certainly driving drunk is a terrible thing,
link |
get you or other people killed, and so on.
link |
But rarely do we hear about the changes in neural circuits
link |
from just one or two nights of regular drinking.
link |
Again, chronic drinking doesn't necessarily mean
link |
every day and every night.
link |
It could be the person that simply drinks
link |
every Thursday or every Friday
link |
or just once a week has three or four drinks
link |
or maybe even a few more.
link |
That person is going to experience
link |
a decrease in this top-down inhibition,
link |
so an increase in impulsivity and habitual behavior
link |
because the break on those behaviors
link |
has been removed while they're drinking,
link |
but also changes in the very neural circuits
link |
that allow habitual and impulsive behavior
link |
to occur more readily even when they're not drinking.
link |
And if you want to know the actual substrate for that,
link |
the cellar substrate, I can briefly describe it.
link |
It's really interesting.
link |
Again, you don't need to know any biology
link |
to understand this.
link |
What it does is it increases the number of synapses,
link |
the actual points of connection in the neural circuits
link |
that control habitual behavior.
link |
So there's literally a growth of the neural circuits
link |
in your brain that lead to existing habit execution, right?
link |
The performance of things you already know how to do
link |
and a reduction in the neural circuits,
link |
or I should say a reduction in the number of synapses
link |
of the contacts within the neural circuits
link |
that are controlling behavior.
link |
So this again is a not often discussed aspect
link |
of alcohol intake.
link |
Fortunately, it is reversible.
link |
So in animals or humans that undertake a period
link |
of abstinence of anywhere from two to six months,
link |
these neural circuits return to normal,
link |
except in cases where people have been chronically
link |
drinking large volumes of alcohol for many, many years.
link |
And in those cases, while there is some recovery
link |
of brain circuitry after people get sober,
link |
meaning completely sober, they stop drinking entirely,
link |
there is evidence of long lasting impact
link |
of heavy alcohol usage throughout the lifespan.
link |
But of course, this doesn't mean that anyone
link |
that's suffering from alcoholism or that used to
link |
should not continue to focus on their health.
link |
You absolutely should, all is not lost.
link |
But for people that have been drinking for a lot of years,
link |
maybe you went to college and you drank a lot in those years
link |
and your neural circuits change.
link |
If there's a period in which you don't drink alcohol,
link |
again, from two to six months and ideally longer,
link |
those neural circuits can then be re-modified
link |
back to their original state.
link |
So let's consider some of the other neurochemical effects
link |
of alcohol in the brain and body.
link |
And again, for right now, we're confining the conversation
link |
to people that are drinking on average,
link |
one or two drinks per night.
link |
Now, some people might think that two drinks per night
link |
is a lot and a lot of that will depend on body weight.
link |
So for instance, people who weigh 110 pounds,
link |
for them to ingest two alcoholic drinks
link |
is going to be substantially different
link |
in terms of the biochemical effects
link |
than somebody who weighs 220 pounds.
link |
Of course, tolerance will also factor into this,
link |
genetic background will also factor into this
link |
and indeed whether or not people have eaten
link |
will factor into this.
link |
So there are a lot of factors and we'll talk about that.
link |
For the time being, if you're curious about how food impacts
link |
the effects of alcohol and your feelings of being drunk,
link |
you may have heard, for instance,
link |
that if somebody is inebriated and they want to sober up,
link |
they should eat something, turns out that does not work.
link |
Here's how it does work, however.
link |
If you eat something prior to drinking alcohol
link |
or while ingesting alcohol,
link |
it will slow the absorption of alcohol into the bloodstream.
link |
In other words, you won't feel as drunk as fast.
link |
For many of you, this probably comes as no surprise.
link |
In particular, if that meal includes carbohydrates,
link |
fats, and proteins, okay?
link |
The inclusion of all three major macronutrients
link |
seems to slow the absorption of alcohol into the bloodstream
link |
far more than having any one of those
link |
or two of those macronutrients present.
link |
Now, if you are already inebriated
link |
or you've had a glass of wine or a beer
link |
and you eat something,
link |
chances are that alcohol has already made it
link |
into your bloodstream
link |
because it moves into the bloodstream so quickly.
link |
Again, it's fat soluble and water soluble,
link |
so within minutes, right?
link |
If you have an empty stomach,
link |
within five to 10 minutes,
link |
that alcohol is going to be within your bloodstream
link |
and distributed throughout your body,
link |
maybe even faster depending on the type of alcohol
link |
and your metabolism.
link |
But if you're already drunk and you eat something,
link |
it's not going to sober you up more quickly,
link |
but it certainly will blunt the effects
link |
of any additional alcohol that you might consume.
link |
And if you're somebody who is concerned
link |
about getting too drunk too quick,
link |
even from a small amount of alcohol,
link |
having some food in your gut can certainly be beneficial.
link |
Now, that's food and alcohol and the absorption of alcohol,
link |
but let's go back to talking about the biochemical
link |
and neurochemical effects of alcohol on the brain.
link |
We talked about top-down inhibition
link |
and we talked about habitual
link |
and impulsive behavior circuitry.
link |
There are also dramatic changes in the activity of neurons
link |
that control the release of so-called serotonin.
link |
Serotonin is a neuromodulator.
link |
It changes the activity of neural circuits
link |
and many neural circuits,
link |
in particular, those involved in mood
link |
and feelings of wellbeing.
link |
Recently, there's been a lot of interest in serotonin
link |
because of a study that was released
link |
that showed pretty conclusively
link |
that serotonin levels can't really explain depression
link |
and depression-like symptoms.
link |
I want to make it very clear
link |
that although that study did show that serotonin levels
link |
are not necessarily associated with depression,
link |
the study was interpreted by many to mean
link |
that SSRI, selective serotonin reuptake inhibitors,
link |
which have the net effect of increasing serotonin,
link |
these are things like Prozac, et cetera,
link |
that those drugs are somehow not helpful
link |
because they increase serotonin
link |
and serotonin isn't involved in depression.
link |
That logic doesn't really hold together,
link |
so I'm going to use this as an opportunity
link |
to just clarify what really occurred there,
link |
and then we'll talk about how serotonin
link |
relates to alcohol consumption
link |
in things like feeling good and in depression.
link |
The key thing is this,
link |
SSRIs can help alleviate depression.
link |
That's right, SSRIs can help alleviate depression.
link |
They are often not always associated with side effects,
link |
dosage is very important, et cetera,
link |
but they probably support relief from depression
link |
by changing neural circuits,
link |
not necessarily by increasing serotonin itself.
link |
That is, increasing serotonin with these drugs
link |
likely change the neural circuits involved in mood,
link |
allowing people to feel better
link |
through so-called neuroplasticity,
link |
which is the brain's ability to change itself
link |
in response to experience.
link |
So there's a bit of confusion,
link |
and again, I'm using this episode on alcohol
link |
to highlight some of the confusion
link |
because I think it's timely,
link |
because the study just came out
link |
and there's a lot of chatter about this out there,
link |
that when people are depressed,
link |
it's not necessarily because serotonin levels are low.
link |
However, if serotonin levels are increased
link |
with things like Prozac, Zoloft, and other SSRIs,
link |
oftentimes there is, yes, a relief from depression,
link |
but that's probably not
link |
because of restoring serotonin levels per se,
link |
it's probably because serotonin
link |
facilitates the changes in neural circuits
link |
that need to occur in order for people
link |
to feel elevated mood, okay?
link |
So again, that's a bit of a tangent and aside,
link |
but I do think it's a vital one for people to know about.
link |
Again, if you're thinking about taking SSRIs,
link |
you're currently taking them and you've heard this news,
link |
definitely talk to your doctor.
link |
Again, there is great utility for some of these SSRIs
link |
and also in conditions like OCD,
link |
they've been shown to be very beneficial,
link |
so we really don't want to throw SSRIs out
link |
as a potentially valuable treatment.
link |
Getting back to the effects of alcohol on serotonin,
link |
it's very clear beyond any doubt
link |
that many of the circuits in the brain
link |
that are involved in mood and feelings of wellbeing
link |
and also sort of self-image in how we see ourselves
link |
employ the neuromodulator serotonin and alcohol
link |
when we ingest it and it's converted into acetaldehyde,
link |
it goes and that acetaldehyde acts as a toxin
link |
at the very synapses,
link |
the connections between the serotonergic neurons
link |
and lots of other neurons.
link |
In other words, when we ingest alcohol,
link |
the toxic effects of alcohol disrupt those mood circuitries
link |
at first making them hyperactive, that's right,
link |
making them hyperactive,
link |
this is why people become really talkative,
link |
people start to feel really good
link |
after a few sips of alcohol, at least most people do,
link |
and then as they can ingest more alcohol
link |
or as that alcohol wears off,
link |
serotonin levels and the activity of those circuits
link |
really starts to drop and that's why people feel less good
link |
and typically what they do, they go and get another drink
link |
and they attempt to kind of restore that feeling
link |
of wellbeing and mood.
link |
Now, typically what happens is that as people ingest
link |
the third and fourth, maybe even the fifth drink,
link |
there's an absolute zero chance of them recovering
link |
that energized mood, right?
link |
Most people as they drink more and more
link |
will now start to feel more and more suppressed.
link |
The forebrain is now shutting down quite a lot,
link |
a lot of the motor cortical areas
link |
that control coordinated movement
link |
and deliberate movement start to shut down
link |
so people start to slur their speech,
link |
people start to shuffle their feet,
link |
people forget their posture,
link |
people start to lean on things,
link |
people start passing out on couches,
link |
there's a great depression,
link |
not depression of the psychiatric depression sort,
link |
but a depression of alertness and arousal
link |
and eventually people will pass out.
link |
Now, I said most people because there's a subset of people
link |
that have gene variants or who are chronic drinkers
link |
or who are chronic drinkers and have gene variants
link |
that as they ingest the third and fourth and fifth drink,
link |
They become more alert, they start talking more,
link |
they feel great, they have all sorts of ideas
link |
about the fun they could have that night
link |
and they're the ones that if you've ever fallen asleep
link |
at a party for whatever reason or you're getting tired
link |
and you're yawning, you're looking around the room
link |
and like these people are still drinking and partying
link |
and they're having what seems to be this amazing time,
link |
often not always, those are the future alcoholics
link |
in the room or those are the people
link |
that have a genetic predisposition for alcoholism
link |
or those are the chronic drinkers,
link |
the people who have built up enough of a tolerance
link |
or who have the chemical genetic makeup
link |
such that increasing amounts of alcohol
link |
make them feel better and better and better
link |
and of course, they too have a threshold
link |
beyond which their nervous system
link |
will start to get diminished and they'll pass out
link |
and fall over, et cetera,
link |
but that threshold is way, way higher
link |
than it is for most people.
link |
Now, this is important to understand
link |
and it's important to understand
link |
because I think everyone should know
link |
and recognize their own predisposition
link |
and kind of risk in terms of developing alcoholism.
link |
It's also important to understand
link |
because it relates to the phenomenon of blackout.
link |
Many people think that blacking out is passing out,
link |
but blackout drunk is when people drink
link |
and they're talking and doing things,
link |
sometimes sadly or tragically, they'll often drive home
link |
or walk home or they'll hop on a bicycle and ride home
link |
or they'll go swimming in the ocean,
link |
all of course, very dangerous activities
link |
to do when people are really drunk or even a little bit drunk
link |
So these people will do these sorts of things
link |
and they do them because they have the energy to do them
link |
and they feel good while doing them,
link |
but they are doing them while the activity of neurons
link |
in the hippocampus, which is involved in memory formation
link |
are completely shut off and this is why the next day
link |
you tell them, hey, maybe we should talk about
link |
what happened last night, like what happened last night?
link |
He said, well, do you remember going to the party?
link |
Yeah, no, it was great, we did this, we did this
link |
and then what, and it's very clear all of a sudden
link |
that they have no recollection of all the things
link |
they were doing despite being awake.
link |
Now, I wish I could tell you that there's some sort
link |
of blood test or other biomarker, even a fingerprint test
link |
that would allow you to determine whether or not
link |
you have a propensity to be one of these drinkers
link |
that has a predisposition for alcoholism
link |
and if you've ever been blackout drunk
link |
and certainly if you've been blackout drunk
link |
more than a few times, you should be quite concerned
link |
and as we talk more about the more chronic effects
link |
and long lasting effects of alcohol consumption
link |
a little bit later in the episode,
link |
I think it will become clear
link |
as to why you should be concerned.
link |
But in any case, there is something that can tell you
link |
whether or not you might be in that category
link |
versus likely not in that category
link |
and I alluded to this a couple of times already
link |
but I want to be really clear that when people drink,
link |
no matter who you are, initially there's that shutting down
link |
of those prefrontal cortical circuits,
link |
there's a gradual shutting down of the circuits
link |
that control memory but then people divide
link |
into these two bins and these two bins are the people
link |
who after more than a couple of drinks start to feel sedated
link |
and the people who after more than a few drinks
link |
do not start to feel sedated.
link |
Now, of course, there's going to be differences
link |
created by how quickly people are drinking,
link |
whether or not they're combining different types of alcohol,
link |
the types of alcohol, et cetera, but in general,
link |
that can predict whether or not you're somebody
link |
who has a predisposition for alcoholism or not.
link |
One also very interesting finding
link |
is that alcohol changes the relationship
link |
between what's called the hypothalamus
link |
and the pituitary gland and the adrenals.
link |
Now, the hypothalamus is a small collection of neurons
link |
about the size of a large gumball
link |
sits above the roof of your mouth
link |
and it houses neurons that are responsible
link |
for some incredible aspects of our behavior and our mindset,
link |
things like rage, things like sex drive,
link |
things like temperature regulation,
link |
very primitive functions,
link |
including appetite, thirst, et cetera.
link |
Alcohol, because it can go anywhere in the brain,
link |
remember it's water and fat soluble,
link |
has effects on the hypothalamus.
link |
The hypothalamus normally provides very specific signals
link |
to what's called the pituitary gland.
link |
This is a little gland that actually sticks out of the brain
link |
but it receives instructions from the hypothalamus
link |
and then the pituitary releases hormones
link |
into the bloodstream that go and talk to your adrenals,
link |
your adrenal glands sit right above your kidneys
link |
in your lower back
link |
and the adrenals release, as the name suggests,
link |
adrenaline, also called epinephrine,
link |
and also a molecule called cortisol,
link |
which is involved in the kind of longer-term stress response
link |
has some healthy effects too on the immune system.
link |
Okay, so the hypothalamic-pituitary-adrenal axis,
link |
I know that's a mouthful,
link |
you don't need to remember the names,
link |
but the hypothalamic-pituitary-adrenal axis
link |
maintains your physiological balance
link |
of what you perceive as stressful
link |
and what you don't perceive as stressful.
link |
People who drink regularly,
link |
so this again could be just one or two drinks per night,
link |
or it could be somebody that drinks just on Fridays
link |
or just on Saturdays, or maybe just on the weekend,
link |
two to four drinks,
link |
well, those people experience changes
link |
in their hypothalamic-pituitary-adrenal axis
link |
that result in more cortisol,
link |
more of this so-called stress hormone
link |
being released at baseline when they are not drinking.
link |
This is really important.
link |
People who drink a bit, and when I say a bit,
link |
I don't mean one or two sips
link |
or even a glass of wine every once in a while.
link |
I mean, again, people that are maybe having
link |
one drink a night with dinner
link |
and maybe on the weekend a few more.
link |
Again, I offer a bunch of different patterns
link |
to explain how it could also be
link |
two or three drinks on Friday
link |
or six drinks only on Saturday.
link |
Well, all of those groups experience increases
link |
in cortisol release from their adrenal glands
link |
when they are not drinking.
link |
And as a consequence, they feel more stressed
link |
and more anxiety when they aren't drinking.
link |
This is a seldom-talked-about effect of alcohol
link |
because so often we hear about
link |
the immediate effects of alcohol, right?
link |
And we've been talking about some of those effects,
link |
effects like reducing the amount of stress.
link |
I mean, how many times have we heard somebody say,
link |
oh, I need a drink, and then they have a drink,
link |
and they're like, calm down.
link |
Now they can shake off the thoughts about the day's work.
link |
They can start to think about things
link |
in a maybe more grounded or rational way,
link |
or at least they believe that,
link |
or they can somehow just relax themselves.
link |
Well, while that very well may be true,
link |
that it can relax them, when they are not drinking,
link |
that level of cortisol that's released at baseline
link |
has increased substantially.
link |
Again, this relates to a defined neural circuit
link |
between brain and body,
link |
and it has to do with the ratio of cortisol
link |
to some of the other hormones
link |
involved in the stress response.
link |
We'll provide a reference to the study
link |
that describes how all of this works
link |
for those of you that really want to delve into it.
link |
But let's go back to this issue
link |
of those who are prone to alcoholism
link |
versus those who are not.
link |
Remember, there are people who have genetic variants,
link |
that meaning genes that they inherited from their parents,
link |
that make it more likely that they will become alcoholics,
link |
but there are also people who drink often,
link |
who start to experience this increase in alertness
link |
the longer they drink across the night.
link |
Part of that effect, we think,
link |
is because of changes
link |
in this hypothalamic-pituitary-adrenal axis.
link |
So alcohol is kind of a double hit in this sense.
link |
It's causing changes in our brain circuitry
link |
and neurochemistry that,
link |
at the time in which we're inebriated, are detrimental,
link |
and it's causing changes in neural circuitry
link |
that persist long past the time
link |
in which we're experiencing the feeling
link |
of being tipsy or drunk.
link |
Now, again, I don't want to demonize alcohol.
link |
I'm not saying, oh, you know,
link |
if you have a glass of wine now and again,
link |
or you drink a beer now and again,
link |
or even have, you know, a mixed drink now and again,
link |
or a shot, that that's necessarily terrible for you.
link |
I certainly do not want that to be the message.
link |
What I'm saying is that
link |
if people are ingesting alcohol chronically,
link |
even if it's not every night,
link |
there are well-recognized changes in neural circuits.
link |
There are well-recognized changes in neurochemistry
link |
and there are well-recognized changes
link |
in the brain-to-body stress system
link |
that generally point in three directions,
link |
increased stress when people are not drinking,
link |
diminished mood and feelings of wellbeing
link |
when people are not drinking,
link |
and, as you'll soon learn,
link |
changes in the neural circuitry
link |
that cause people to want to drink even more
link |
in order to get just back to baseline
link |
or the place that they were
link |
in terms of their stress modulation
link |
and in terms of their feelings of mood
link |
before they ever started drinking in the first place.
link |
So again, I don't want to demonize alcohol,
link |
but I do want to emphasize
link |
that there are long-term plastic changes,
link |
meaning changes in neural circuitry and hormone circuitry,
link |
that across a period of several months
link |
and certainly across a period of years
link |
of the sorts of drinking patterns I described,
link |
which I think for most people
link |
are going to sound like pretty typical, right?
link |
I mean, nothing that I described so far
link |
was about drinking a case a night
link |
or about binging on alcohol
link |
in the way that we often hear about it in the news.
link |
These are pretty common patterns of alcohol consumption.
link |
I mean, all you have to do is board a transatlantic flight
link |
or actually go to an airport on a Sunday afternoon
link |
in a sunny area of the US,
link |
and people are having three, four, five, six beers, et cetera.
link |
Again, personal choice is personal choice.
link |
I'm not telling you what to do,
link |
but it's very clear that those sorts of drinking patterns
link |
are changing neural circuitry
link |
and they're changing hormone circuitry,
link |
and I'd love to be able to tell you
link |
that they're changing them for the better,
link |
but they simply are not.
link |
They're actually changing them for the worse,
link |
and worse is defined as making people less resilient
link |
to stress, higher levels of baseline stress,
link |
and lower mood overall.
link |
Before we continue with today's discussion,
link |
I'd like to just briefly acknowledge our sponsor,
link |
Athletic Greens, now called AG1.
link |
Athletic Greens, aka AG1,
link |
is an all-in-one vitamin mineral probiotic drink
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that also has adaptogens and digestive enzymes.
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I've been taking Athletic Greens since way back in 2012,
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so I'm delighted that they're sponsoring the podcast.
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The reason I started taking Athletic Greens
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and the reason I still drink Athletic Greens twice a day
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is that it supplies total foundational coverage
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of my vitamin mineral needs,
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and it supplies important nutrients that I need
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to support my gut microbiome.
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The gut microbiome, as many of you know,
link |
supports the immune system.
link |
It also supports the so-called gut-brain axis,
link |
which is vital for mood, for energy levels,
link |
for regulating focus,
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and many other features of our mental health
link |
and physical health that impact our daily performance
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and high performance in any endeavors
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we might be involved in.
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If you'd like to try Athletic Greens,
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you can go to athleticgreens.com slash Huberman
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and claim a special offer.
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They're giving away five free travel packs
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plus a year supply of vitamin D3K2 with every order.
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And of course, vitamin D3K2 are vital
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for all sorts of things like hormone health
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and metabolic health and K2 for cardiovascular health
link |
and calcium regulation.
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Again, you can go to athleticgreens.com slash Huberman
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to claim that special offer.
link |
Now I've been talking a little bit
link |
about genetic predisposition,
link |
but there are a couple of important points
link |
I'd like to make about that.
link |
First of all, what sorts of genes are involved
link |
in setting someone down the path of alcoholism or not?
link |
Well, it should come as no surprise
link |
that the genes that chronic alcohol usage modifies,
link |
they tend to fall primarily in the pathways
link |
related to genetic control over serotonin receptors,
link |
GABA receptors, remember that top-down inhibition
link |
and the involvement of GABA,
link |
and no surprise, the HPA, the hypothalamic pituitary axis.
link |
All of those, of course, combined with environment,
link |
they combine with patterns of abuse, right?
link |
We know that if you're in a social setting
link |
where a lot of people are drinking,
link |
the likelihood that you're going to drink is much higher.
link |
Social pressures, trauma, right?
link |
Some people will use alcohol to self-medicate
link |
to try and turn off their thinking
link |
or to deal with trauma, et cetera.
link |
So they combine with the environment,
link |
but the genes that are in the serotonin synthesis
link |
and receptor synthesis pathway, GABA and HPA axis,
link |
combined with environmental pressures
link |
to give rise to alcohol use disorders.
link |
So there's a fairly coherent picture that we have here,
link |
This is not a case where, for instance,
link |
people that have a lot of the enzyme for metabolizing alcohol
link |
which we'll talk about in a minute,
link |
alcohol dehydrogenase,
link |
it's not like they are necessarily
link |
the people that become alcoholics.
link |
Whereas certainly in certain cultures,
link |
certain Asian cultures in particular,
link |
there are gene differences that lead them
link |
to have low levels of alcohol dehydrogenase.
link |
There are actually people who have
link |
so little alcohol dehydrogenase
link |
that when they ingest alcohol,
link |
they get very red and they just feel sick.
link |
So if you're somebody that has a sip of alcohol
link |
and you just feel horrible, it makes you feel nauseous,
link |
chances are you have gene variants that create a situation
link |
where you're not making very much alcohol dehydrogenase,
link |
you just simply can't metabolize alcohol,
link |
so you just get a rapid buildup
link |
of the toxic effects of alcohol, the acetaldehyde,
link |
you're not converting it into those empty calories.
link |
But in cultures where you have a lot of genetic variants
link |
and genes expressed in people
link |
where they have a lot of alcohol dehydrogenase,
link |
sure, they can drink more
link |
and they're converting more of that alcohol
link |
from its toxic form to a non-toxic form.
link |
And yes, of course, you will observe more alcoholism
link |
in those communities because they're drinking more,
link |
but I do want to emphasize that the environmental factors
link |
are playing a strong role there too,
link |
because if you can drink more, you're likely to drink more.
link |
If you're somebody that feels sick immediately from drinking,
link |
it's likely that you're not going to engage
link |
in alcohol consumption,
link |
especially if these things are genetically related
link |
and of course, genes and culture and location in the world
link |
tend to run together.
link |
So do you have the gene for alcoholism?
link |
Well, there isn't one single gene.
link |
Chances are if you have an immediate relative
link |
who's a chronic abuser of alcohol
link |
or several relatives who are chronic abusers of alcohol,
link |
well, that's going to predispose you to be an alcoholic.
link |
But since you don't know which genes you express
link |
unless you do genetic testing and those things are available
link |
but most people aren't doing that,
link |
this assay, if you will, and it's not an assay,
link |
as we say, an assay is a test that you run in the lab
link |
to determine something.
link |
And it's not one that I recommend
link |
that you go drink in order to do.
link |
But if you've noticed that you or somebody else
link |
is somebody who can drink a lot throughout the night
link |
and have increased energy
link |
and can just drink and drink a drink,
link |
and especially if there's blackout episodes,
link |
not remembering things the next day
link |
despite being alert throughout the entire night and so on,
link |
well, then I would be very concerned
link |
that you might actually have a genetic variant
link |
predisposing you to alcoholism.
link |
The other thing that predisposes people
link |
to abuse of alcohol is age.
link |
People who start drinking at younger ages
link |
are greatly predisposed to developing alcohol dependence
link |
regardless of your family history of alcoholism, okay?
link |
So I'm going to repeat that.
link |
People who start drinking younger
link |
are at great risk for developing alcoholism
link |
even if they don't have alcoholism in their family.
link |
Now, of course, you don't have to be an epidemiologist
link |
to understand that if you grew up in a family of drinkers
link |
and alcohol is everywhere,
link |
and especially if there's peer pressure
link |
or lack of oversight,
link |
then there's going to be a higher tendency
link |
or a higher probability, I should say,
link |
that you will start drinking at a younger age.
link |
However, even people that grow up
link |
nowhere near their relatives,
link |
if they start drinking at a young age,
link |
so for instance, at 13 or younger or 14 or 15,
link |
there's a much higher probability
link |
that they're going to develop
link |
a long-lasting dependence on alcohol.
link |
People who take their first sip of alcohol later,
link |
15, 16, or one would hope even later,
link |
I can say one would hope
link |
because I'm now of that age and generation
link |
where you think about all the things that young people do
link |
and you go, oh gosh, if they only would wait
link |
or if they only would abstain,
link |
it's just what happens.
link |
I don't know, there's some neural circuit for that
link |
that I can't explain yet.
link |
But people who, for instance,
link |
drink only once they reach legal age of drinking,
link |
which in the US, I believe in every state is 21 years old,
link |
if they take their first drink at 21,
link |
the probability that they'll go on
link |
to develop full-blown alcohol dependence
link |
or alcohol use disorder as it's called, AUD, is very low.
link |
Now, a subset of them will
link |
because they have such a strong genetic predisposition
link |
or maybe life circumstances create a pattern
link |
in which they become a chronic drinker.
link |
But I found this very interesting.
link |
Genes matter, but also the age
link |
in which somebody starts drinking really matters.
link |
Now, whether or not that's because there are changes
link |
in neural circuitry as a consequence of that drinking
link |
that make people want to seek out more and more alcohol,
link |
or whether or not there's some other effect,
link |
maybe it's a change in hormones, et cetera,
link |
that predisposes those young drinkers to become
link |
chronic drinkers or even full-blown alcoholics,
link |
certainly developing alcohol use disorder.
link |
There's definition for that.
link |
We can talk about it.
link |
It involves the amount of drinking
link |
over a certain period of time, et cetera.
link |
So it's very clear that drinking early in life
link |
creates a propensity for the development
link |
of alcohol use disorder later in life.
link |
And while there is a genetic component
link |
to developing alcohol use disorder,
link |
I find it very interesting that if people
link |
who have those gene variants delay their onset of drinking,
link |
well, then the probability that they'll develop
link |
full-blown alcohol use disorder drops as well.
link |
So again, it's genes and environments,
link |
not an either or, and there's no single gene for alcoholism.
link |
Well, I promise you, I will also talk about
link |
some of the documented positive effects of alcohol.
link |
Although they are very few and far between, they do exist.
link |
But before I do that, I would be remiss
link |
if I didn't emphasize some more of the terrible things
link |
that alcohol does and the way that it does it.
link |
And for those of you that enjoy alcohol,
link |
I, again, I really, I like to say I feel guilty
link |
about telling you this because I know
link |
how much some people enjoy a good drink
link |
every once in a while, and I say a good drink
link |
because some people do like the taste of alcohol.
link |
I suppose I lucked out in that I don't really like
link |
the taste of alcohol and that just puts me to sleep,
link |
but I know that people do enjoy it.
link |
And I do want to point out that there is zero evidence
link |
that, you know, provided somebody is of drinking age,
link |
or certainly not in the stage of brain development,
link |
that having one drink or two drinks every now and again,
link |
meaning every three or four weeks or once a month,
link |
that is not going to cause major health concerns
link |
or major health issues for most people.
link |
I suppose if you have zero
link |
or very little alcohol dehydrogenates,
link |
it might make you feel sick,
link |
but then you're probably not the kind of person
link |
that's going to be drinking at all.
link |
So again, if you enjoy alcoholic drinks,
link |
I'm not trying to take them away from you by any means,
link |
but you should know what drinking does
link |
if you're consuming it in this kind
link |
of typical chronic pattern, as we can now refer to it,
link |
which is that one or two a night,
link |
or a few stacked up on Friday
link |
and maybe three or four on Saturday,
link |
this kind of pattern of drinking, which is quite common.
link |
And one of the more serious effects
link |
that we should think about is the impact
link |
on the so-called gut-brain axis,
link |
or for sake of today's discussion, the gut-liver-brain axis.
link |
I don't think the gut-liver-brain axis
link |
has ever been discussed on this podcast.
link |
Maybe any podcast, although the moment I say that,
link |
I'm going to, you know, the gut-liver-brain axis,
link |
people are going to come after me
link |
with, I suppose, gut, liver, brain, and brains.
link |
In any event, you have a brain, you have a gut.
link |
That gut runs from your throat
link |
down to the end of your intestine.
link |
Your gut and your brain communicate
link |
by way of nerve cells, neurons, and nerve connections,
link |
the vagus nerve in particular,
link |
and by way of chemical signaling.
link |
Your gut also communicates by way of chemical signaling,
link |
and believe it or not,
link |
by way of neural signaling to your liver.
link |
And as we talked about earlier,
link |
the liver is the first site in which alcohol
link |
is broken down and metabolized into its component parts.
link |
The liver is also communicating with the brain
link |
through chemical signaling and neural signaling.
link |
So we have the gut-liver-brain axis.
link |
And what you find is that people who ingest alcohol
link |
at any amount are inducing a disruption
link |
in the so-called gut microbiome,
link |
the trillions of little micro-bacteria
link |
that take resident in your gut
link |
and that live inside you all the time
link |
and that help support your immune system
link |
and that literally signal by way of electrical signals
link |
and chemical signals to your brain
link |
to increase the release of things like serotonin
link |
and dopamine and regulate your mood
link |
generally in positive ways.
link |
Well, alcohol really disrupts those bacteria.
link |
And this should come as no surprise.
link |
I mean, earlier we talked about this and it's well-known.
link |
If you want to sterilize something,
link |
you want to kill the bacteria, you pour alcohol on it.
link |
And I can remember scraping myself or cutting myself.
link |
I was always injuring myself when I was a kid.
link |
And the moment they take out the peroxide,
link |
you're like, oh boy, here it comes.
link |
But if there's no peroxide around
link |
and you've got a wound there and you need to clean it out,
link |
yeah, they'll use alcohol,
link |
which I do not recommend by the way.
link |
That's one of the harshest ways to clean a wound.
link |
But for centuries, thousands of years really,
link |
alcohol has been used in order to clean things
link |
and kill bacteria.
link |
So alcohol kills bacteria and it is indiscriminate
link |
with respect to which bacteria it kills.
link |
So when we ingest alcohol and it goes into our gut,
link |
it kills a lot of the healthy gut microbiota.
link |
At the same time, the metabolism of alcohol in the liver,
link |
which you now understand that pathway involving NAD,
link |
acetaldehyde and acetate, that pathway is pro-inflammatory.
link |
So it's increasing the release of inflammatory cytokines,
link |
things like IL-6, et cetera, tumor necrosis factor alpha.
link |
If you'd like to learn more about the immune system,
link |
we did an episode all about the immune system.
link |
You can find it at hubermanlab.com.
link |
It'll teach you all the basics of what are cytokines,
link |
what are mast cells, et cetera.
link |
In any event, all these pro-inflammatory molecules,
link |
those are being released.
link |
You've now got disruption of the gut microbiota.
link |
As a consequence, the lining of the gut is disrupted
link |
and you develop at least transiently leaky gut.
link |
That is bacteria that exists in the gut,
link |
which are bad bacteria,
link |
can now pass out of the gut into the bloodstream.
link |
So you've got a two hit kind of model here.
link |
In biology, we talk about two hit models
link |
that it's kind of a one plus one equals four.
link |
And it's generally when you hear two hit,
link |
it's not a good thing.
link |
So you've got bad bacteria from partially broken down food
link |
moving out of the gut.
link |
The good bacteria in the gut have been killed.
link |
You might say, why doesn't the alcohol
link |
kill the bad bacteria in the gut?
link |
Well, the bad bacteria that are from partially digested food
link |
oftentimes escape the gut
link |
before the alcohol can disrupt them.
link |
And so now you've got leaks in the gut wall.
link |
You've got the release of this bad bacteria.
link |
You've got inflammatory cytokines
link |
and other things being released from the liver.
link |
And they are able to get into the brain
link |
through what's called a neuro-immune signaling.
link |
And what's really bizarre in terms of the way
link |
that this manifests in the brain.
link |
I mean, it's not the way I would have done it.
link |
But then again, as I always say,
link |
I wasn't consulted at the design phase.
link |
And anyone who says they did,
link |
you should be very skeptical of them.
link |
The net effect of this is actually to disrupt
link |
the neural circuits that control regulation
link |
of alcohol intake.
link |
And the net effect of that is increased alcohol consumption.
link |
So this is just terrible, right?
link |
I mean, so you're taking in something
link |
that disrupts two systems, the gut microbiota,
link |
and it disrupts in two ways.
link |
It's killing the good gut microbiota,
link |
and it's allowing the bad bacteria
link |
to move from the gut into the bloodstream.
link |
You've also got pro-inflammatory cytokines
link |
coming from the liver.
link |
And those converge or arrive in the brain
link |
and create a system in which the neural circuits
link |
cause more drinking.
link |
That's a bad situation.
link |
And this is why people who drink regularly,
link |
even if it's not a ton of alcohol,
link |
again, of the sorts of patterns of drinking
link |
I talked about before,
link |
and certainly for those that are chronic heavy drinkers,
link |
what you end up with is a situation
link |
in which you have inflammation
link |
in multiple places in the brain and body,
link |
and the desire to drink even more
link |
and to further exacerbate that inflammation
link |
and the gut leakiness.
link |
So this is basically a terrible scenario
link |
for the gut-liver-brain axis.
link |
And it's especially prevalent
link |
in so-called alcohol use disorder.
link |
Again, people that are ingesting
link |
somewhere between 12 and 24 drinks per week.
link |
For those of you that are interested
link |
in learning more about the gut-liver-brain axis
link |
and in particular alcohol use disorder,
link |
I'll provide a link in the show note captions.
link |
There's a wonderful review on this that details that.
link |
But on the positive side,
link |
it points to the possibility that at least some,
link |
again, at least some of the negative effects
link |
of alcohol consumption,
link |
whether or not you're somebody
link |
who's currently ingesting alcohol
link |
or who used to ingest alcohol
link |
and is trying to so-called repair these systems
link |
of the brain and body,
link |
whether or not replenishing the gut microbiota
link |
is going to be beneficial.
link |
And we know that there are ways to do that.
link |
And we know that there's at least some promise
link |
for the ability for the system to repair itself.
link |
How does one do that?
link |
Well, I've talked before about this on the podcast,
link |
but studies done by colleagues of mine at Stanford,
link |
Justin Sonnenberg, who's been on this podcast as a guest,
link |
an amazing episode all about the gut microbiome
link |
and his collaborator, Chris Garner,
link |
also at Stanford School of Medicine
link |
have explored not alcoholism,
link |
but what are ways to improve the gut microbiota
link |
in particular to reduce
link |
the production of inflammatory cytokines
link |
and to adjust what's called the inflammatome.
link |
You've heard of the genome and the proteome, et cetera.
link |
Well, the inflammatome is the total array
link |
or at least the near total array of genes and proteins
link |
that control inflammation.
link |
How can you reduce inflammation
link |
and make that inflammatome healthier?
link |
Well, they've shown that two to four servings
link |
of fermented foods per day,
link |
and here I'm not referring to fermented alcohol,
link |
I'm talking about low sugar fermented foods,
link |
so things like kimchi, sauerkraut, natto,
link |
for those of you that like Japanese food.
link |
There are others, I know things like kefir,
link |
things like yogurts that have a lot of active bacteria,
link |
again, low sugar varieties of all these things.
link |
Those are terrific at reducing inflammatory markers
link |
and at improving the gut microbiome.
link |
One could imagine that either inoculating oneself
link |
from some of the effects of alcohol,
link |
although I'd prefer that people
link |
just not drink alcohol chronically, frankly,
link |
or if somebody is trying to repair their gut microbiome
link |
because they ingested a lot of alcohol
link |
or because they had a lot of these inflammatory cytokines
link |
for many years or even a short period of time,
link |
regular ingestion of two to four servings
link |
of these fermented foods can be quite beneficial.
link |
I want to make it clear that has not been examined
link |
specifically in the context of alcohol use disorder,
link |
but because a huge component of the negative effects
link |
of alcohol use disorder are based
link |
in this gut-liver-brain axis and disruption
link |
of the gut microbiome and the inflammatory cytokines,
link |
it stands to reason that things that are well-established
link |
to improve inflammation status,
link |
in other words, reduce inflammation,
link |
such as ingesting two to four servings
link |
of low-sugar fermented foods per day,
link |
makes sense in terms of trying to repair
link |
or replenish the system.
link |
One could also imagine taking probiotics or prebiotics.
link |
Certainly that would work as well,
link |
although I've sort of favored the discussion
link |
around fermented foods and replenishment
link |
of the gut microbiome,
link |
mostly because there are more studies
link |
that have examined that in humans
link |
and because of the direct relationship
link |
that's been established between doing that
link |
and reducing negative markers within the inflammatome.
link |
And I should mention along the lines of repair and recovery,
link |
I put out a question on Twitter the other day.
link |
I said, what do you want to know about alcohol?
link |
I got more than a thousand questions,
link |
and we'll take some more of those questions
link |
a little later in the episode.
link |
But one of the things I noticed
link |
is that many of the questions, hundreds in fact,
link |
related to the question of,
link |
well, if I drank a lot previously, am I doomed?
link |
Can I reverse the negative effects?
link |
Or, you know, I'm trying to drink less
link |
and I'm trying to improve my health as I do that.
link |
Well, certainly focusing a bit on the gut microbiome
link |
ought to be useful.
link |
The other thing I should mention is
link |
as people wean themselves off alcohol,
link |
even if they're not full-blown alcoholics
link |
or have alcohol use disorder,
link |
they should understand that that increase in cortisol
link |
that we talked about earlier
link |
that leads to lower stress threshold
link |
and greater feelings of anxiety and stress,
link |
that's going to be present
link |
and it's going to take some time to dissipate.
link |
So for some people, it might even just be helpful to realize
link |
that as you try and wean yourself off alcohol
link |
or maybe even go cold turkey,
link |
that increased anxiety and feelings of stress
link |
should be expected.
link |
And in that case, I would point you to an episode
link |
that we did on master stress.
link |
You can find that again at hubermanlab.com.
link |
It's got a ton of behavioral, nutritional,
link |
supplementation-based, exercise-based,
link |
I suppose exercise is behavioral,
link |
but a lot of tools, you can navigate to those easily
link |
because we have timestamps.
link |
You can go right to the topic of interest.
link |
Those tools are going to be very useful
link |
in trying to clamp or control your stress.
link |
And the point here is just that
link |
some increase in stress should be expected
link |
and it should be expected
link |
because of that increase in cortisol
link |
that occurs with even low-level consumption
link |
yet chronic alcohol consumption.
link |
Now I'd like to talk about a fairly common phenomenon,
link |
which is post-alcohol consumption malaise,
link |
also referred to as hangover.
link |
Hangover is a constellation of effects
link |
ranging from headache to nausea
link |
to what's sometimes called a anxiety,
link |
which is anxiety that follows a day of drinking.
link |
Anxiety, I think we can understand physiologically
link |
if we think about that process of alcohol intake
link |
increasing the amount of cortisol
link |
and the ratio of cortisol to some other stress hormones.
link |
That well explains why some people wake up the day after
link |
or even the day after a night drinking
link |
and feel anxious and not well and stressed
link |
for reasons they don't understand.
link |
So if you're somebody who experiences anxiety,
link |
then again, I refer you to the master stress episode
link |
that we put out some time ago
link |
and you can find that at hubermanlab.com.
link |
Tools to deal with anxiety, tools to deal with stress
link |
ranging again from behavioral
link |
to nutritional supplement-based, et cetera.
link |
That of course is not justification
link |
for going out and drinking so much
link |
that you get anxiety-induced hangover.
link |
But for those of you that are experiencing
link |
post-alcohol consumption, hangxiety as it were,
link |
that could be a useful resource
link |
because I certainly don't want anyone
link |
experiencing uncomfortable amounts of anxiety
link |
and there are great tools and resources for that.
link |
Now, the other aspects of hangover
link |
such as the stomach ache or headache
link |
or feelings of malaise or fogginess,
link |
those can be related to a number of different things
link |
and probably are related to a number of different things.
link |
First of all, the sleep that one gets after even just one,
link |
yes, even just one glass of wine or a beer
link |
is not the same sleep that you get
link |
when you don't have alcohol circulating in your system.
link |
And not trying to be a downer here,
link |
but this was discussed in the Huberman Lab podcast episode
link |
where I had Dr. Matthew Walker from UC Berkeley on
link |
and of course, Dr. Walker is a world expert in sleep,
link |
runs one of the preeminent laboratories
link |
studying sleep and its effects,
link |
wrote the incredible book, Why We Sleep and so on.
link |
Dr. Walker told me, and it certainly is supported by
link |
lots and lots of quality peer-reviewed studies
link |
in animals and in humans,
link |
that when alcohol is present in the brain and bloodstream,
link |
that the architecture of sleep is disrupted.
link |
Slow wave sleep, deep sleep and rapid eye movement sleep,
link |
all of which are essential
link |
for getting a restorative night's sleep are all disrupted.
link |
So for those of you that are drinking
link |
a glass or two of wine
link |
or having a hard liquor drink or a beer
link |
in order to fall asleep,
link |
the sleep you're getting is simply not high quality sleep
link |
or certainly not as high quality
link |
as the sleep you'd be getting
link |
if you did not have alcohol in your system.
link |
Of course, when we're talking about hangover,
link |
we're talking generally about the consumption
link |
of more than just one or two drinks.
link |
Of course, for some people,
link |
one or two drinks is probably sufficient to induce hangover,
link |
but for most people, it's going to be having three or four
link |
exceeding their typical limit, as it's called.
link |
Again, not the legal limit.
link |
That's a whole other business.
link |
But when one ingests too much alcohol for them,
link |
one of the reasons they feel terrible the next day
link |
is because their sleep isn't really good sleep.
link |
In fact, it's not even sleep.
link |
It's often considered pseudo sleep,
link |
or at least that's what it's called
link |
in the sleep science field,
link |
because people are in kind of a low level hypnotic
link |
It's not real sleep.
link |
There are multiple bouts of waking up.
link |
They may not even realize they're waking up multiple times.
link |
Okay, so there's the sleep-induced effects.
link |
Then there are the disrupted gut microbiome effects,
link |
some of which we talked about earlier.
link |
So now you understand the mechanism
link |
of alcohol destroying good, healthy gut microbiota,
link |
which then leads to leaky gut and things of that sort.
link |
But one could imagine, again, could imagine,
link |
and there is some evidence starting to support this,
link |
that, again, ingesting low-sugar fermented foods
link |
or maybe in prebiotic or probiotic
link |
to support the gut microbiome
link |
might assist in some of the gut-related malaise
link |
associated with hangover.
link |
In other words, get those gut microbiota healthy again
link |
as quickly as possible,
link |
or maybe even before you drink,
link |
have those gut microbiota healthy.
link |
I would hope that you would do that.
link |
I think everybody should be doing something
link |
to support their gut microbiome,
link |
whether or not it's the ingestion
link |
of low-sugar fermented foods daily
link |
or at least on a regular basis,
link |
or ingestion of probiotic or prebiotic.
link |
The gut microbiome is so important
link |
for so many different things.
link |
In terms of hangover and headache,
link |
we know that that's caused by vasoconstriction,
link |
the constriction of blood vessels
link |
that tends to occur as a rebound after a night of drinking.
link |
Alcohol can act as a vasodilator.
link |
It can dilate the blood vessels.
link |
Part of that is associated with the increase
link |
in so-called parasympathetic tone.
link |
We have an autonomic nervous system.
link |
It's got a sympathetic component.
link |
These are neurons that make us more alert,
link |
and if they're very active, they make us very stressed.
link |
There's also the parasympathetic aspect
link |
of the autonomic nervous system.
link |
This is all just fancy geek speak
link |
for the parts of your brain and body,
link |
the nerve cells that make you very relaxed.
link |
When you're very relaxed, there tends to be vasodilation.
link |
It allows for more movement of blood and other things
link |
through the bloodstream,
link |
and alcohol tends to induce some vasodilation,
link |
at least in some of the capillary beds,
link |
and then when the alcohol wears off,
link |
there's vasoconstriction, and people get brutal headaches.
link |
That's why some people will take aspirin or Tylenol
link |
or Advil or things like that,
link |
the sort of non-steroid anti-inflammatories.
link |
I should mention there's a lot of literature coming out
link |
that some of these non-steroid anti-inflammatory drugs
link |
are not good for us for a number of different reasons,
link |
the way they impact the liver,
link |
the way they impact the immune system,
link |
and no surprise, the way they impact the gut microbiome.
link |
So I'm not one to tell you what medications
link |
to take or not take, but you certainly would want to do
link |
a quick web search of effects of non-steroid
link |
anti-inflammatories and aspirin before you start taking those
link |
or stop taking those for that matter.
link |
Generally, they will alleviate headache,
link |
but they can often have other issues, including liver issues
link |
and keep in mind, the night after drinking,
link |
your liver has already taken a beating
link |
because of the need of the liver to convert alcohol
link |
from acetaldehyde into acetate,
link |
which is now a pathway that you well understand.
link |
So I'm not certain, and in fact,
link |
I believe it's not the greatest idea
link |
to burden your liver further through the use of things
link |
that are going to cause it to have to work harder
link |
and metabolize things if the goal is simply
link |
to alleviate a headache.
link |
There's a lot of kind of lore,
link |
old school lore about how to relieve a hangover.
link |
We already talked about how eating food won't do that,
link |
but eating food will prevent the rapid absorption
link |
of even more alcohol into the bloodstream.
link |
There's the lore that one should simply ingest
link |
more alcohol, what terrible advice that is,
link |
that's just going to delay an even worse hangover.
link |
However, I'd be remiss if I didn't say
link |
that the reason that that myth came to be,
link |
or that I should say that truth came to be,
link |
because indeed ingesting more alcohol
link |
will alleviate a hangover,
link |
but then a worse hangover will show up.
link |
The reason that came to be is because ingestion
link |
of more alcohol will cause those constricted vessels
link |
that are giving the headache to dilate again,
link |
but of course, ingesting more alcohol
link |
to relieve a hangover is simply a bad idea.
link |
I think this is called the hair of the dog approach.
link |
Maybe someone can put in the show note captions on YouTube
link |
why it's called the hair of the dog.
link |
I can come up with a few ideas,
link |
but they're not going to be very good ones.
link |
And some of them would probably even be outright ridiculous.
link |
So do not ingest more alcohol simply to try
link |
and recover from a hangover.
link |
I know many people have tried that one before,
link |
but that's a terrible idea.
link |
Now, one thing that you'll also hear out there
link |
is that deliberate cold exposure,
link |
for instance, taking a cold shower might relieve hangover.
link |
I find this one particularly interesting
link |
because we've done episodes on the benefits
link |
of deliberate cold exposure.
link |
We have an entire episode about that.
link |
You can find it again, hubermanlab.com.
link |
There are direct links to some of the tools
link |
related to deliberate cold exposure.
link |
And we have an entire newsletter
link |
on deliberate cold exposure protocols.
link |
You can find on hubermanlab.com
link |
go to our neural network newsletter.
link |
So those of you that are interested in ice baths
link |
and cold showers and ways to leverage those,
link |
you can find that there.
link |
What you won't find there is a description
link |
of how to use deliberate cold exposure
link |
for sake of treating hangover.
link |
But here I went into the literature
link |
and I found something kind of interesting.
link |
There is some evidence that increasing levels of epinephrine
link |
in the bloodstream can actually help with alcohol clearance.
link |
That was very surprising to me.
link |
And I want to point out this is not a large
link |
and robust literature, but there's some evidence
link |
pointing to the fact that when levels of epinephrine,
link |
adrenaline, are raised in the brain and bloodstream,
link |
that some of the components of alcohol metabolism
link |
can be accelerated and some of the inebriating effects
link |
of alcohol can be reduced.
link |
So maybe this old school lore of taking a cold shower
link |
actually has something to it.
link |
So in thinking about the use of deliberate cold exposure
link |
in order to reduce the effects of hangover
link |
or to more rapidly clear alcohol
link |
from the brain and bloodstream,
link |
I want to be very clear and I want to emphasize your safety.
link |
The way to do that is to understand
link |
that alcohol lowers core body temperature, okay?
link |
It can make people slightly hypothermic.
link |
It's going to drop core body temperature.
link |
So if you were inebriated and you went
link |
and got into a body of water, right?
link |
A pool or a lake or something,
link |
first of all, that's extremely dangerous to do
link |
while you're inebriated, right?
link |
People drown all the time.
link |
People drown, they die as a consequence of doing that.
link |
So please don't do that.
link |
But also if it's a very cold water,
link |
your core body temperature is going to drop even further.
link |
Now, if you've heard the episodes
link |
that I've done on deliberate cold exposure,
link |
previously I've talked about how normally
link |
when people are not ingesting alcohol,
link |
they get into an ice bath or a cold shower
link |
and their body temperature initially dips,
link |
but then it rebounds and increases.
link |
That's a process that's going to occur
link |
when people do not have alcohol in their system.
link |
When you have alcohol in your system,
link |
one of the reasons that you become hypothermic
link |
is because there's a disruption
link |
in those hypothalamic brain areas,
link |
in particular the brain area called the medial preoptic area
link |
that regulates core body temperature.
link |
So it's not so much that alcohol makes you cold,
link |
it's that alcohol disrupts the central command centers
link |
of the brain that control temperature regulation
link |
and that leads you to be slightly hypothermic.
link |
So if you then go get into a very cold lake
link |
or you get into even a cold shower or an ice bath,
link |
there's the possibility of you going very, very far
link |
down the ladder into very hypothermic territory
link |
and that can be very dangerous.
link |
Now, in terms of dealing with hangover
link |
when the alcohol has been largely cleared from your system,
link |
well, that's where some of this kind of old lore
link |
combines with some of the modern science and says,
link |
well, if you can spike adrenaline
link |
and certainly getting into an ice bath
link |
or getting into a cold shower
link |
or any kind of cold body of water
link |
provided you can do that safely,
link |
that will sharply increase your adrenaline
link |
and I should say your dopamine, that's been shown
link |
and we've talked about this on the podcast before,
link |
you get these long extended increases,
link |
several hours of increases in dopamine
link |
from deliberate cold exposure.
link |
It's well-documented in humans, by the way.
link |
So one could imagine using deliberate cold exposure
link |
as a way to accelerate the recovery from hangover
link |
provided that's done safely.
link |
I think there's no reason to not explore that
link |
and if you wonder what safely is
link |
and what temperatures to use,
link |
please check out the episode on deliberate cold exposure.
link |
Cold showers therefore might actually be one way
link |
to at least partially relieve hangover.
link |
Certainly the science from various places in the literature
link |
converge to say that, but again, be careful,
link |
please, please, please be careful
link |
not to get into cold water when you are inebriated.
link |
It's absolutely dangerous for all the obvious reasons
link |
and it's dangerous also for the non-obvious reasons,
link |
not the least of which is the dramatic decreases
link |
in core body temperature
link |
that can make you dangerously hypothermic.
link |
Now, how would you go about using deliberate cold exposure
link |
to accelerate recovery from hangover?
link |
Well, there I would look to the kind of standard protocols
link |
of one to three minutes or maybe even six minutes
link |
if you can tolerate or if you're really cold adapted,
link |
maybe you do seven or 10 minutes in a cold shower,
link |
although that could be a lot.
link |
Most people are going to experience a sharp increase
link |
in epinephrine and adrenaline
link |
and a long lasting increase in dopamine
link |
from one to three minutes of deliberate cold exposure,
link |
ideally done immersion up to the neck.
link |
Again, do this safely, please, please, please
link |
or a cold shower where you're getting under the shower
link |
as much as possible.
link |
Well, that's going to vary person to person.
link |
I suggest making it as cold as is uncomfortable
link |
such that you really want to get out,
link |
but then you know you can stay in safely without,
link |
for instance, giving yourself a heart attack
link |
because if the water is really, really cold,
link |
of course you can give yourself a heart attack.
link |
Most showers won't go that cold,
link |
although probably some will.
link |
Again, please use caution, spike your adrenaline,
link |
spike your dopamine with deliberate cold exposure safely.
link |
Other components of hangover that could be good targets
link |
for trying to alleviate hangover,
link |
and here I hope you are getting the picture
link |
because it is accurate to say that hangover
link |
is a multifaceted phenomenon.
link |
It's not like one molecule and one receptor,
link |
it's a bunch of things happening in the brain and body,
link |
but is the dehydration associated with alcohol?
link |
Alcohol is a diuretic for multiple reasons.
link |
It causes people to excrete not only water, but also sodium.
link |
Sodium is an electrolyte critical
link |
for the function of neurons.
link |
So making sure that you have enough sodium, potassium,
link |
and magnesium, so-called electrolytes
link |
is going to be important for proper brain function,
link |
bodily organ function.
link |
Even for people that have just had one or two drinks
link |
the night before, it's likely that your electrolyte balance
link |
and your fluid balance is going to be disrupted,
link |
and that's because alcohol also disrupts
link |
the so-called vasopressin pathway.
link |
I talked a lot about vasopressin
link |
and the way that it interacts with
link |
and controls different aspects of water retention
link |
and water release from the body in the form of urine
link |
in the episode on salt.
link |
So again, I'm referring to Hubermanlab.com
link |
as the site where you can find that episode on salt balance
link |
and ways to restore electrolyte balance.
link |
Having your electrolytes at the proper levels
link |
before you drink is ideal.
link |
Some people will say for every glass of alcohol
link |
that you drink, you should drink one glass of water.
link |
I would say better would be two glasses of water
link |
given the dehydrating effects of alcohol,
link |
and even better would be water with electrolytes.
link |
That certainly would set you up for a better day
link |
And if you don't manage to do that,
link |
because I suppose it's kind of geeky
link |
walking around with electrolyte packets
link |
out at the bar or whatnot,
link |
although, you know, geeky in my book is a good thing,
link |
the next day you could take some electrolytes upon waking,
link |
maybe even some before you go to sleep
link |
at the night of drinking.
link |
So hangovers made worse by disturbed sleep,
link |
made worse by disrupted gut microbiome,
link |
made worse by disrupted electrolytes,
link |
made worse by the depletion of epinephrine and dopamine.
link |
That's why replenishing the microbiome with fermented foods,
link |
low sugar fermented foods that is,
link |
that's why using safe deliberate cold exposure
link |
for spiking adrenaline and for increasing dopamine.
link |
And that's why consuming electrolytes
link |
are all going to be beneficial.
link |
The folks over at examine.com, a website that I really like
link |
because it just has so much useful information,
link |
have assembled a list of things that have been proposed,
link |
purported to improve, or I should say,
link |
to remove the effects of hangover.
link |
And as they point out, and I would like to point out
link |
over there, there isn't a lot of quality science
link |
to support the idea that any one compound
link |
can eliminate hangover.
link |
And that's probably because hangover, again,
link |
arises from multiple organs and tissues and systems
link |
in both the brain and body.
link |
Nonetheless, they have a terrific list over there of things,
link |
everything from Japanese pear fruit juice
link |
has been proposed to do this
link |
to some other really esoteric things,
link |
even things like yohimbine.
link |
Frankly, when I look at the literature,
link |
there and elsewhere,
link |
one simply cannot find the magic substance,
link |
the one herb, the one potion that can wipe away hangover.
link |
Getting rid of hangover is going to be best solved
link |
by doing a collection of a small number
link |
of very powerful things,
link |
of which I've already listed off a few.
link |
However, there are some additional things
link |
that one can do for relieving hangover.
link |
And one of them is to be very thoughtful
link |
about what sorts of alcohol one consumes.
link |
So I find this interesting.
link |
There have actually been studies
link |
of which types of alcohol lead to the greatest hangovers.
link |
There's actually a lot of legend and lore about this as well.
link |
Some people have said, for instance,
link |
that drinks that have a high sugar content
link |
lead to greater hangovers.
link |
Turns out that's not the case,
link |
or at least that's not what the science points to.
link |
If you look at the expected hangover severity,
link |
what you find is that at the bottom end of the scale,
link |
there's a drink that I'm not going to tell you for the moment
link |
but what you find is that near it is, for instance, beer.
link |
The consumption of beer,
link |
provided it is not over consumption, right?
link |
It's not far beyond the tolerance of the individual.
link |
So there's one or two beers,
link |
is less likely to cause a hangover than say whiskey.
link |
And a glass of whiskey,
link |
or I should not as much whiskey as beer, of course,
link |
but a glass of whiskey, for instance,
link |
is more likely to cause hangover than gin, as it turns out.
link |
Again, this is what's fallen out of the data.
link |
And yet a glass of rum or red wine
link |
is more likely to cause a hangover
link |
than any of the other things I've mentioned so far.
link |
At the top, top, top of the list of drinks
link |
that induce hangover is brandy.
link |
And one could then say,
link |
well, doesn't brandy have a lot of sugar?
link |
Maybe it's the sugar that's causing hangovers.
link |
And this is something that's been, again,
link |
discussed over and over that people say,
link |
oh, it's the high sugar drinks that cause hangover.
link |
It turns out, however, that when one looks at drinks,
link |
alcoholic drinks and sugar content and hangover,
link |
at the very bottom of the list is,
link |
gosh, this makes me cringe just to think about,
link |
is ethanol diluted in orange juice?
link |
Ugh, I can't believe people actually drink this,
link |
but ethanol diluted in orange juice.
link |
So this is not vodka and orange juice, okay?
link |
Vodka was third on the list from the bottom
link |
of drinks that induce hangover.
link |
Again, this is within amounts that are comfortable
link |
for the person to drink,
link |
that they have enough experience with
link |
or that they have the body weight to tolerate
link |
without getting very, very drunk.
link |
So the point is that if it were sugar
link |
that's causing hangover,
link |
well, then the ethanol diluted in orange juice
link |
would probably be at the top of the list
link |
in terms of inducing hangover, but it's not.
link |
It's at the bottom of the list.
link |
And brandy is at the top of the list.
link |
So what you find is that what scales
link |
from ethanol diluted in orange juice
link |
to beer to vodka to gin,
link |
here I'm ascending the hierarchy of things
link |
that cause hangover, gin, white wine, whiskey,
link |
rum, red wine, and then brandy at the peak,
link |
it's sort of the world heavyweight champion
link |
of hangover inducing drinks.
link |
Well, what's increasing are congeners within those drinks.
link |
Congeners are things like nitrites and other substances
link |
that give alcohol its distinctive flavor
link |
and that also lead to some of the
link |
inebriating effects of alcohol.
link |
Now then you ask, okay, well,
link |
what is it that these congeners are doing
link |
and what are these nitrates doing?
link |
While they do have effects on the brain
link |
and on other tissues,
link |
their main effects are to disrupt the gut microbiome.
link |
So what this points to again
link |
is that having a healthy gut microbiome
link |
and perhaps ensuring that you bolster your gut microbiome,
link |
the day after drinking is going to be especially important
link |
for warding off hangover,
link |
or at least reducing the effects of hangover
link |
or the symptoms of hangover or both.
link |
I would love to see a study on this.
link |
I could imagine designing the study myself,
link |
although this isn't really the sorts of things
link |
my laboratory does,
link |
but you can imagine some people getting probiotic
link |
and prebiotic, some regularly,
link |
some just after drinking or low sugar fermented foods
link |
and see what the effects are
link |
in terms of subjective effects of hangover,
link |
but also some physiological measures.
link |
I think the way to think about hangover overall
link |
is that, again, it represents a multifaceted,
link |
multi-organ, multi-tissue phenomenon.
link |
And the best way to deal with it
link |
is as a multi-cell, multi-tissue, multi-chemical phenomenon.
link |
And before I listed off some of the things
link |
that one could do in order to adjust hangover,
link |
again, the one that comes out at the top of that list,
link |
I believe, at least based on my read of the data,
link |
is to support the gut microbiome
link |
and certainly not to ingest more alcohol.
link |
And I suppose if we were to get really honest
link |
with one another and ask what's the best way
link |
to avoid a hangover,
link |
it would be to not drink in the first place.
link |
So we've covered the major effects of alcohol
link |
that lead to this state that we call
link |
drunkenness or inebriation.
link |
Again, there's a range there.
link |
It can be tipsy, people can be blackout drunk,
link |
people can be passed out drunk.
link |
We've also talked about hangover
link |
and the fact that it's a multifaceted phenomenon
link |
and recovery from hangover
link |
involves a multifaceted approach.
link |
Next, I want to talk about tolerance.
link |
Tolerance to alcohol is a very interesting phenomenon.
link |
It has roots mainly in the brain and in brain systems.
link |
There's not time in the world,
link |
let alone within this podcast,
link |
to get into all the aspects of tolerance.
link |
There are more than 10 different types of tolerance.
link |
There's functional tolerance,
link |
chronic tolerance, rapid tolerance.
link |
There's metabolic tolerance.
link |
There's psychological tolerance.
link |
Let's keep it simple for sake of today's discussion.
link |
And for those of you that are interested in learning
link |
about all the different types of tolerance
link |
and aspects of tolerance,
link |
there's an excellent review.
link |
We will provide a link to this.
link |
This was published in 2021.
link |
So it's pretty recent in the journal
link |
Pharmacology, Biochemistry and Behavior.
link |
Incidentally or not so incidentally,
link |
that was the first journal I ever published in.
link |
So I have a particular affection for that journal.
link |
Nonetheless, it is called tolerance to alcohol,
link |
a critical yet understudied factor in alcohol addiction.
link |
And while this paper does include alcohol addiction
link |
in the title, it's not just about alcohol addiction.
link |
Here's the basic summary of what tolerance is.
link |
First of all, tolerance refers to the reduced effects
link |
of alcohol with repeated exposure.
link |
And it is caused mainly by changes
link |
in neurotransmitter systems in the brain
link |
that are the direct consequence of the toxicity of alcohol,
link |
that aldehyde molecule that we talked about before.
link |
There's an enormous number of chemicals that change
link |
with repeated exposure to acetaldehyde,
link |
everything from GABA to dopamine to serotonin,
link |
second messenger systems, adenosine and on and on.
link |
Rather than go into each of those in detail,
link |
I just want to talk about the contour of the reinforcing
link |
and the tolerance inducing effects of alcohol.
link |
What do I mean by that?
link |
Well, here we are back to our old friend,
link |
meaning the molecule that comes up over and over again
link |
in these podcast episodes, which is dopamine.
link |
Whether or not somebody has a predisposition alcoholism
link |
or not, whether or not they're experienced drinker or not,
link |
when people initially start drinking,
link |
there are increases in dopamine
link |
or what we call dopaminergic transmission.
link |
Dopamine is involved in motivation, craving,
link |
it creates a sense of wellbeing, it increases energy,
link |
again, typically only at the beginning of alcohol exposure.
link |
That occurs in most people as a sharp spike,
link |
Again, if somebody does not have alcohol dehydrogenase
link |
or has very low levels of the enzyme
link |
that convert that acetaldehyde into acetate
link |
and metabolize alcohol, in other words,
link |
they will feel sick and lousy in a way
link |
that will override any recognition of the dopamine release.
link |
They're going to be the people that are listening to this
link |
and just think alcohol just makes me feel sick,
link |
Okay, that's a specific subcategory of people,
link |
but most people experience some sort of mild euphoria,
link |
that's why so many people drink, right?
link |
The current estimates are that in most countries
link |
and certainly in the US,
link |
as many as 80% of the adult legal drinking age population
link |
drinks alcohol and that number could be even higher now
link |
because in the last couple of years,
link |
there's been a trend towards increased alcohol consumption,
link |
especially in the wake of the pandemic
link |
and during the pandemic topic for another time.
link |
So there's an increase in dopamine
link |
and an increase in serotonin,
link |
so it's kind of an increase in wellbeing,
link |
an increase in mood, but it's a very short-lived increase.
link |
Very soon after and actually triggered by that increase
link |
is a long and slow reduction in dopamine and serotonin
link |
and related molecules and circuits.
link |
So basically what you're getting is a blip of feel good
link |
followed by a long, slow arc of feeling not so great,
link |
which is why typically people will drink again and again
link |
The key thing to understand about tolerance
link |
is that with tolerance,
link |
the duration of that long, slow reduction
link |
in dopamine and serotonin gets even longer.
link |
In other words, the negative effects of alcohol
link |
that happen after the initial feeling good extend longer
link |
and in fact get more robust.
link |
However, there's also a reduction
link |
in the reinforcing properties of alcohol.
link |
There's a shrinking of the feel good blip
link |
that happens when one first ingests alcohol.
link |
And this has been measured in animals and humans.
link |
So the first drink that somebody has,
link |
provided they have enough alcohol dehydrogenase
link |
that doesn't make them feel nauseous and sick right away,
link |
they feel really good.
link |
And then as it wears off, they feel kind of lousy
link |
and they want to drink more, so they might drink more.
link |
With each subsequent drink and even drinks
link |
on different nights or even different weeks,
link |
the amount of dopamine that's released is reduced.
link |
The amount of serotonin that's released is reduced.
link |
So what you're getting is less and less
link |
of the reinforcing properties of alcohol,
link |
the feel good stuff,
link |
and more and more of the punishment
link |
pain signal aspects of alcohol.
link |
This is the contour of chemical release in the brain
link |
that was referred to by my colleague,
link |
the incredible Dr. Anna Lemke, who's a medical doctor.
link |
She wrote the incredible book, Dopamine Nation.
link |
She was a guest on this podcast, on Joe Rogan's podcast,
link |
on Rich Roll's podcast, and several other podcasts.
link |
World expert in addiction,
link |
and she talked about this pleasure pain balance
link |
that extends beyond alcohol to things like sex and gambling
link |
and to other behaviors that can potentially become addictive
link |
but certainly includes alcohol.
link |
So tolerance, it seems, is a process in which people
link |
are ingesting more and more alcohol
link |
as an attempt to get that feeling of wellbeing back.
link |
But what they're really getting is an extended period
link |
of punishment, of pain, and of malaise from the alcohol.
link |
Now you might say, well, how does that relate to tolerance?
link |
Well, it turns out what they do behaviorally,
link |
and when I say they, I mean, animals do this
link |
and humans do this, is they start drinking more and more
link |
in an attempt to activate those dopamine
link |
and serotonin neurons and receptors.
link |
And as they do that,
link |
there is an increase in alcohol dehydrogenase.
link |
So the enzyme that metabolizes alcohol is increased
link |
because the body and liver have to contend
link |
with all that alcohol.
link |
So now you've got, again, the two hit model.
link |
You're getting less of the feel-good chemicals,
link |
more of the negative chemical release
link |
or pattern of subjective feeling, I should say,
link |
and you're metabolizing alcohol more quickly
link |
and more readily, but it's not taking you to a better place
link |
in terms of how you feel.
link |
That's one of the major underlying reasons
link |
for what we call tolerance.
link |
So if you're somebody who drinks
link |
and you notice that the feeling
link |
that you are seeking with alcohol
link |
is now requiring an additional drink or drinks, plural,
link |
chances are you are disrupting the dopamine
link |
and serotonergic systems of your brain,
link |
and you are doing that in a way that is increasing
link |
the pain and punishment signals
link |
that follow alcohol ingestion.
link |
And again, that's not just on the night
link |
that you're drinking, but afterwards as well.
link |
Is that all bad news?
link |
Well, pretty much, but the good news is
link |
that if you abstain from drinking for some period of time,
link |
then of course these systems reset.
link |
How long you need to abstain
link |
will depend on how much you were drinking
link |
and how long you were drinking for.
link |
Certainly people who have alcohol use disorder
link |
who are alcoholics,
link |
their main goal should be to quit alcohol completely.
link |
I know there's some debate about this,
link |
and I don't want to get into that debate
link |
because I'm certainly not going to try
link |
and direct anyone's recovery.
link |
There are expert counselors and MDs
link |
and people that can work with people.
link |
In fact, for some very heavy drinkers
link |
and people with serious alcohol use disorder,
link |
going cold turkey that is stopping drinking completely
link |
can actually be medically dangerous.
link |
So the path to sobriety for certain people
link |
looks different than the path to sobriety for other people.
link |
What I'm referring to here
link |
are people that are ingesting again
link |
somewhere between on average one to two drinks per night,
link |
whether or not that's done night to night
link |
or whether or not that's condensed to weekend use.
link |
I know a number of people are going to ask,
link |
perhaps are screaming,
link |
is drinking good for me in any way?
link |
For instance, many people have probably heard
link |
that resveratrol is good for people
link |
and that red wine is enriched in resveratrol.
link |
I hate to break it to you,
link |
but the reality is that if indeed resveratrol is good for us
link |
and there's some debate about this,
link |
some people say strongly yes,
link |
some people say no,
link |
other people say maybe,
link |
the amount of red wine that one would have to drink
link |
in order to get enough resveratrol
link |
in order for it to be health promoting
link |
is so outrageously high that it would surely
link |
induce other negative effects
link |
that would offset the positive effects of resveratrol.
link |
So I wish I could tell you different.
link |
Again, I'm not here to be the bearer of bad news,
link |
but the statement I just made was confirmed
link |
by Dr. David Sinclair
link |
when he was a guest on this podcast.
link |
It's confirmed by other researchers
link |
who work on resveratrol and related pathways.
link |
I wish I could tell you that red wine
link |
is good for your health,
link |
and indeed it might be through some other mechanisms.
link |
So for instance, there have been studies
link |
of low to moderate red wine consumption.
link |
This would be anywhere from one to four glasses per week,
link |
and I don't mean enormous glasses,
link |
I mean six ounce glasses of red wine.
link |
And in those cases,
link |
some of the stress reduction that can be induced
link |
by consumption of red wine,
link |
maybe some of the other micronutrients and components
link |
in particular red wines that come from particular grapes,
link |
and this gets really nuanced,
link |
and frankly is not well worked out
link |
in the peer-reviewed literature,
link |
certainly not clinical trials,
link |
at least not that I'm aware of.
link |
Tell me if you're aware of a great clinical trial on this.
link |
Well, there may be some positive effects
link |
of that very low level of consumption.
link |
I'm not trying to take away anybody's red wine.
link |
I'm not trying to take away anybody's anything.
link |
I would be remiss, however,
link |
if I didn't tell you that resveratrol
link |
as the argument for drinking
link |
and drinking red wine in particular is just not a good one.
link |
It's just not supported by the peer-reviewed research.
link |
A few other things about alcohol and health.
link |
The beginning of the episode,
link |
I referenced a study showing that indeed,
link |
not just heavy alcohol consumption
link |
of 12 to 24 more drinks per week,
link |
but also light to moderate alcohol consumption
link |
of any type, wine, beer, spirits, et cetera,
link |
does reduce the thickness of the brain.
link |
It really does reduce cortical thickness.
link |
In fact, it actually scales with the amount of alcohol
link |
that people drink.
link |
And this has been well-documented
link |
in a number of different studies.
link |
I can provide a link to several of these.
link |
One of the more striking ones actually shows
link |
that there's almost a dose-dependent increase
link |
in shrinkage of the gray matter volume
link |
and in these white matter tracks, these axons,
link |
these wires, as it would, that connect different neurons
link |
as a function of how much alcohol people drink.
link |
And that's also what's been seen in this recent study
link |
that I referenced at the beginning,
link |
and that's in the show note captions.
link |
So again, probably the best amount of alcohol to drink
link |
would be zero glasses per week or ounces per week.
link |
For those of you drinking low amounts of alcohol,
link |
make sure you're doing other things to promote your health.
link |
And for those of you that are drinking moderate,
link |
and certainly for those of you that are heavy drinkers,
link |
please do everything you can to move away from that
link |
and to quit entirely.
link |
But even for the moderate consumers of alcohol,
link |
you are going to want to be aware of some
link |
of the negative health effects and do things to offset those
link |
if indeed you're not going to stop drinking
link |
or reduce your intake.
link |
One of the really bad effects of alcohol,
link |
but that's extremely well-documented,
link |
is the fact that alcohol,
link |
because of this toxicity of acetaldehyde
link |
and related pathways, can alter DNA methylation,
link |
it can alter gene expression.
link |
That can be many things in different tissues,
link |
but it is associated with a significant increase
link |
in cancer risk, in particular, breast cancer.
link |
And in particular, because breast tissue is present
link |
in both males and females, but in women,
link |
it's especially vulnerable
link |
to some of the DNA methylation changes.
link |
Well, breast cancer in women has a relationship
link |
to alcohol intake and alcohol intake has a relationship
link |
to breast cancer in women.
link |
In fact, there has been proposed to be anywhere from four
link |
to 13% increase in risk of breast cancer
link |
for every 10 grams of alcohol consumed.
link |
How much is 10 grams?
link |
Well, there we need to think a little bit
link |
about the variation in the amount of alcohol
link |
in different drinks across the world.
link |
Different countries serve different sized drinks
link |
and have different concentrations of alcohol in those drinks.
link |
So without going down too much of a rabbit hole
link |
and just giving you some good rules of thumb to work with,
link |
there have been studies of the percentage of alcohol
link |
included in different drinks and the sizes
link |
of different drinks that are served in different countries.
link |
And here's a kind of a patchwork of those findings.
link |
In Japan, one beer, one glass of wine,
link |
or one shot of liquor as it's served there tends
link |
to include anywhere from seven to eight grams of alcohol.
link |
In the US, one beer, which generally is 12 ounces,
link |
if it's in a bottle, one glass of wine or a shot of liquor
link |
tends to include about 10 to 12 grams of alcohol.
link |
And in Russia, one drink of the various sorts
link |
that I just described typically will have
link |
as much as 24 grams of alcohol because of the differences
link |
in the concentration of alcohols and the sizes of drinks
link |
that are poured in these different countries, okay?
link |
Of course, there are other countries in the world,
link |
those countries are also vitally important,
link |
but those are the ones that I extracted from the studies
link |
that I could find.
link |
What does this mean?
link |
Well, what we're talking about is that for every 10 grams
link |
of alcohol consumed, so that's one beer in the US,
link |
maybe a little bit more than one beer in Japan,
link |
or basically a third of a drink in Russia,
link |
there's a 4 to 13% increase in risk of cancer.
link |
That's pretty outrageous, right?
link |
And you might think, wait, how could it be
link |
that this stuff is even legal?
link |
Well, look, as I described before, it's a toxin.
link |
It's also a toxin that people enjoy the effects of.
link |
I mean, in the US, at least they tried prohibition.
link |
It certainly did lead, yes, did lead to a reduction
link |
in alcohol-induced health disorders,
link |
in particular cirrhosis of the liver.
link |
It also led to a lot of crime because it became a substance
link |
that a lot of people still wanted
link |
and that people were willing to break the law
link |
in order to provide, or I should say to sell and provide.
link |
But the point is that the more alcohol people drink,
link |
the greater their increase of cancer,
link |
in particular breast cancer.
link |
And that's because of the fact
link |
that alcohol has these effects on cells
link |
that include changes in gene expression.
link |
And cancer, that is the growth of tumors,
link |
is a dysregulation in cell cycles, right?
link |
A tumor is a aggregation or the proliferation.
link |
Aggregation is stuff sticking together, by the way.
link |
Proliferation is stuff duplicating.
link |
A proliferation and aggregation of cells
link |
that could be a glioma, glial cells, glioma, brain tumor,
link |
right, it could be lymphoma,
link |
so within the lymph tissue, et cetera.
link |
The mutations that alcohol induces to cause this
link |
Some of those are starting to start to be understood.
link |
For those of you that are interested in cell biology,
link |
I'll just mention that the PD-1 pathway,
link |
again, this is super specialized
link |
and for the aficionados only.
link |
You don't need to know this.
link |
The PD-1 pathway seems to be upregulated.
link |
And we knew this from the discussion earlier,
link |
there's a downregulation
link |
in some of the anti-inflammatory molecules
link |
that help suppress this proliferation of cancers.
link |
Nowadays, there's a lot of interest in the fact
link |
that the immune system is constantly combating cancers
link |
that exist in us all the time.
link |
You know, little tumors start growing
link |
and our immune system goes and gobbles them up.
link |
Little tumors start growing,
link |
the immune system senses inflammation,
link |
sends out these incredible cells,
link |
these killers B cells and T cells and beats them up.
link |
Cancers proliferate and take hold and cause serious problems
link |
when the proliferation of cells
link |
exceeds the immune system's ability
link |
to gobble up and remove those cells.
link |
There are other mechanisms of regulating cancers,
link |
but that's one of the primary one.
link |
And alcohol hits it, again, it's a two hit model.
link |
It increases tumor growth and it decreases
link |
the sorts of molecules that suppress
link |
and combat tumor growth.
link |
So again, even low to moderate amounts of alcohol
link |
can be problematic for sake of cancers,
link |
in particular, breast cancers.
link |
Epidemiologists and health specialists
link |
love to try and compare different substances
link |
in terms of how bad they are.
link |
Rarely do they compare substances
link |
in terms of how good they are, but sometimes they do.
link |
And what they'll sometimes tell you
link |
and what you can find in the literature
link |
is that ingesting 10 to 15 grams of alcohol a day,
link |
so that would be like one beer in the US,
link |
one glass of wine,
link |
is the same as smoking 10 cigarettes a day.
link |
Frankly, it's hard to make that direct relationship
link |
really stick because it's a question of
link |
how long people inhale,
link |
do they have a predisposition to a lung cancer, et cetera.
link |
But even if that number is off
link |
by plus or minus two cigarettes,
link |
or even if that number with the equivalent
link |
of one glass of wine equals one cigarette per day,
link |
I think there's general consensus now
link |
that nicotine consumed by vaping or by cigarette,
link |
it's bad for us in terms of lung cancer
link |
and other forms of cancer.
link |
And for some reason, I don't know why,
link |
because this knowledge about alcohol and cancer
link |
and these established relationships
link |
have been known since the late 1980s.
link |
The first landmark paper on this was published in 1987.
link |
I can provide a link to that paper.
link |
It's actually quite interesting to read.
link |
Well, the relationship is there
link |
and yet we don't often hear about it, right?
link |
In fact, before researching this episode,
link |
I had heard before that alcohol can increase cancer risk,
link |
but I wasn't aware of just how strong
link |
that relationship is.
link |
Because of the serious nature of what we're talking about
link |
and because I would hate to be confusing
link |
or misleading to anybody,
link |
I want to just emphasize that this statistic,
link |
that there is a four to 13%,
link |
depending on which study you look at,
link |
a four to 13% increase in the risk of cancer,
link |
in particular breast cancer,
link |
for every 10 grams of alcohol consumed,
link |
that's 10 grams per day.
link |
So that's one drink per day.
link |
But I do want to emphasize that if that equates
link |
to seven drinks per week
link |
and all those seven drinks are being consumed
link |
on Friday and Saturday,
link |
it still averages to 10 grams per day.
link |
And I also want to emphasize
link |
that there are things that people can do
link |
to at least partially offset some of the negative effects
link |
of alcohol as it relates to predisposition
link |
to the formation of certain kinds of tumors and cancers.
link |
I also want to be clear before I say it
link |
that doing the things I'm about to tell you
link |
is not a guarantee that you're not going to get cancer,
link |
nor is it a guarantee that alcohol is not going
link |
to lead to an increased predisposition
link |
for certain kinds of cancers.
link |
And the two things are consumption of folate
link |
and other B vitamins, especially B12.
link |
You know, the consumption of folate and B12
link |
has been shown to decrease cancer risk
link |
in people that ingest alcohol,
link |
but not completely offset it.
link |
Why that is isn't exactly clear.
link |
It probably has something to do with the relationship
link |
between folate and B12 and other B vitamins
link |
in gene regulation pathways that can lead to tumor growth.
link |
At some point soon, we will get an expert in cancer biology
link |
and in particular in breast cancer biology on the program,
link |
and we can ask them about this,
link |
but I realize this is going to raise a number of questions
link |
and maybe even cause some of you to go out there
link |
and start taking folate and other B vitamins and B12.
link |
Not incidentally, a lot of the reported hangover supplements
link |
and treatments include folate and B12.
link |
I don't know if they had the cancer literature in mind
link |
when they created those supplements and products.
link |
Alcohol really does disrupt B vitamin pathways,
link |
both synthesis pathways and utilization pathways.
link |
So sometimes you'll hear,
link |
if you get your B vitamins,
link |
it helps you recover from hangover more quickly.
link |
Again, the literature doesn't support that,
link |
but also again, there aren't a lot of studies,
link |
but more to the point as it relates to alcohol
link |
and the formation of tumors and cancers,
link |
it does appear that decreased folate
link |
and other B vitamins like B12 are partially responsible
link |
for the effect of alcohol and increasing cancer risk.
link |
And it does appear that consuming adequate amounts of folate
link |
and B12 might, again, might partially really want
link |
to bold face and underline and highlight,
link |
partially offset some of that increased risk.
link |
There's an additional category
link |
that I want to highlight, of course,
link |
and this is vitally important to state,
link |
even though it's obvious,
link |
which is that people who are pregnant
link |
should absolutely not consume alcohol.
link |
Fetal alcohol syndrome is well-known and established.
link |
Fetuses experience diminished brain development
link |
that's often permanent, diminished limb development,
link |
diminished organ development in the periphery,
link |
meaning the heart, the lungs, the liver, et cetera.
link |
Ingesting alcohol while pregnant is simply a bad idea.
link |
And the reason I say this at all is,
link |
first of all, it's important to include
link |
in an episode like this,
link |
but also because we can look at two things.
link |
First of all, we can look at mechanism,
link |
and then we can also look at some of the lore
link |
that still sadly exists out there.
link |
Let's take care of the lore that sadly exists first.
link |
If you look online,
link |
you will sometimes be able to find, sadly,
link |
that some people believe that certain kinds of alcohol
link |
are not detrimental to fetuses.
link |
They'll say, well, champagne is safe
link |
for a pregnant mother to drink, but beer is not.
link |
That is absolutely categorically false.
link |
Alcohol is alcohol.
link |
There is no evidence whatsoever
link |
that consuming certain types of alcohol
link |
is safer for fetuses than others.
link |
Alcohol is a toxin,
link |
and the reason fetal alcohol syndrome exists
link |
is because the ability of that toxin
link |
to disrupt cellular processes.
link |
Remember tumor growth and the way that alcohol
link |
can accelerate tumor growth by proliferation of cells,
link |
the wrong cells, the ones you don't want to proliferate?
link |
Well, all of embryonic development,
link |
all of fetal development, it's not the growth of a tumor.
link |
It's obviously the growth of an embryo,
link |
and it's done in a very orchestrated way.
link |
I started off studying brain development.
link |
That's where I got my beginnings in neurobiology,
link |
and I still teach embryology to medical students
link |
and graduate students.
link |
The set of coordinated processes that has to take place
link |
from conception to birth in order to give rise
link |
to a healthy embryo is so dynamically controlled
link |
and so exquisitely precise with checkpoints
link |
and recovery mechanisms and redundancy
link |
in the genes that are expressed to make sure
link |
that if anything goes wrong, it's repaired, et cetera.
link |
Alcohol as a mutagen, I haven't used that word yet,
link |
but a substance that can mutate DNA
link |
through alterations in DNA methylation
link |
and these checkpoints in the cell cycle.
link |
Alcohol as a mutagen is one of the worst things
link |
that a developing embryo can be exposed to.
link |
And again, because it's water-soluble and fat-soluble,
link |
ingestion of alcohol when people are pregnant
link |
passes right to the fetus.
link |
Now, I realize that a number of people out there
link |
might be thinking, oh goodness,
link |
I didn't realize I was pregnant
link |
until a certain stage of pregnancy,
link |
and before I realized I was ingesting alcohol.
link |
Obviously, one can't undo what's been done,
link |
but I want to also emphasize that fetal alcohol syndrome,
link |
while, yes, there's a full-blown syndrome
link |
that manifests as changes in the craniofacial development
link |
that are very obvious, and you can look these up,
link |
you've probably seen these before, the pictures before,
link |
rather, it has to do with eye spacing, forehead size,
link |
a number of other features of the craniofacial development,
link |
and of course, stuff's going on in the brain too.
link |
It's along a continuum.
link |
So it is possible that some of the changes that occur
link |
are more minor, and thankfully, the young brain,
link |
in particular, the early postnatal brain
link |
is incredibly plastic.
link |
There are things that can be done
link |
in order to help recover neural circuits
link |
that didn't develop well, et cetera.
link |
But even though it's somewhat obvious or should be obvious,
link |
I really want to make clear that there's zero evidence
link |
whatsoever that certain forms of alcohol
link |
are safer for pregnant women to ingest than others.
link |
No one who's pregnant should be ingesting alcohol
link |
whatsoever, and certainly, if people feel like
link |
they can't avoid alcohol while pregnant,
link |
they really need to work with somebody
link |
to make sure that it just absolutely doesn't happen
link |
because it is so detrimental to the developing fetus.
link |
Lastly, I want to talk about the effects
link |
of alcohol on hormones, and I want to distinguish
link |
between low amounts of alcohol intake,
link |
higher amounts of alcohol intake,
link |
and again, this chronic alcohol intake
link |
versus occasional use versus really chronic use,
link |
meaning alcoholic or alcoholic use disorder
link |
where people are drinking an immense amount
link |
on an ongoing basis.
link |
The literature on alcohol and hormones is quite extensive,
link |
and there are, of course, many,
link |
many different types of hormones.
link |
The hormones that most often get mentioned
link |
and talked about on this podcast are the hormones
link |
testosterone and estrogen, which are present
link |
in both men and women, and that in both men and women
link |
are important for things like libido.
link |
They're also responsible for sexual development,
link |
actual development of the genitalia
link |
before birth and after birth.
link |
They're responsible, for instance,
link |
estrogen is important for memory and cognition.
link |
You never want to drop estrogen too low in men or women
link |
because it can disrupt cognition and joint health, et cetera.
link |
To keep this discussion relatively constrained,
link |
it's fair to say that alcohol, and in particular,
link |
the toxic metabolites of alcohol,
link |
increase the conversion of testosterone to estrogen.
link |
Now, this occurs in a number of different tissues.
link |
This is not just occurring in the testes of males.
link |
This is occurring in lots of different tissues,
link |
and I'll refer you to a excellent review.
link |
We'll provide a link in the show note captions.
link |
This is a paper that was published in the year 2000,
link |
but the data are still quite strong.
link |
The journal is called, of all things, Alcohol.
link |
There's, yes, literally a journal called Alcohol
link |
for the publication of data and reviews
link |
on alcohol and its effects.
link |
And the title of the paper is,
link |
Can Alcohol Promote Aromatization
link |
of Androgens to Estrogens?
link |
Aromatization is this process of the conversion
link |
of testosterone and other androgens to estrogens
link |
through things like aromatase enzyme.
link |
And this is a beautiful review that describes every tissue
link |
or near every tissue from the ovary in females
link |
to the placenta, to the liver, to the testes,
link |
in which alcohol can increase the aromatization
link |
of testosterone to estrogen.
link |
Now in females, this may be part of the reason
link |
why there's an increase in estrogen-related cancers.
link |
Breast cancer can be either estrogen-related
link |
or non-estrogen-related.
link |
There are other types of estrogen-related cancers
link |
outside of breast cancer,
link |
but it appears that one reason why alcohol increases
link |
the risk of breast cancer is because of this aromatization
link |
from, of testosterone, excuse me, to estrogen.
link |
In males, accelerated or abnormal conversion
link |
of testosterone to estrogen can actually lead to growth
link |
of the breast tissue in males, so-called gynecomastia,
link |
or other effects of high estrogen,
link |
or I should say of altered testosterone-estrogen ratios,
link |
because that's really what's important.
link |
And these can include things like diminished sex drive,
link |
increased fat storage, and a number of other things
link |
that I think most people would find to be negative effects.
link |
I once talked about the fact that drinking alcohol
link |
can increase the aromatization of testosterone to estrogen.
link |
I posted that online and I didn't get attacked,
link |
but I did get criticized for the fact
link |
that it has been shown, yes, has been shown
link |
that small amounts of alcohol ingestion,
link |
so five grams or so of alcohol ingestion,
link |
this would be half a glass of wine or half a glass of beer,
link |
at least in some studies showed increases in testosterone,
link |
which was kind of surprising, but I should point out,
link |
other studies have shown that alcohol ingestion
link |
causes decreases in testosterone over time.
link |
So there's always this issue
link |
of whether or not you're looking at a study
link |
of acute exposure versus chronic exposure,
link |
one dose versus multiple doses and exposure.
link |
I think it's fair to say,
link |
based on my read of the literature,
link |
this review and other reviews
link |
that focus more particularly on humans,
link |
that regular ingestion of alcohol
link |
is going to increase estrogen levels,
link |
whether or not you're male or female,
link |
and it's largely doing that through the aromatization process
link |
by increasing the aromatase enzyme.
link |
Yes, there's some dose dependence,
link |
but I think if you're somebody
link |
who's trying to optimize your testosterone to estrogen ratio,
link |
regardless of whether or not you're male or female,
link |
well, then most certainly you're going to want to avoid
link |
drinking too much alcohol.
link |
So we've covered a lot of topics and data
link |
related to the mechanisms of alcohol, hangover, tolerance,
link |
cancer risk, et cetera.
link |
I acknowledge that I've mainly talked to you
link |
about the negative effects of alcohol.
link |
I want to acknowledge that many people enjoy alcohol
link |
in moderation or even light drinking,
link |
the occasional drink or the occasional two drinks,
link |
or maybe even on average, one drink per night,
link |
so seven drinks per week.
link |
I'm certainly not here to tell you
link |
what to do and what not to do.
link |
I do find it immensely interesting, however,
link |
that first of all, alcohol is a known toxin
link |
to the cells of the body.
link |
Some of you might immediately say,
link |
well, wait, what about hormesis?
link |
What about this phenomenon where if we regularly
link |
ingest a toxin, it makes us stronger?
link |
In other words, what doesn't kill us makes us stronger.
link |
Yeah, there's some reason to believe
link |
that might be beneficial in terms of some forms
link |
of cellular resilience, maybe, maybe, no, sorry.
link |
It doesn't work that way.
link |
There are processes of hormesis in which, for instance,
link |
exposing yourself safely to increases in adrenaline
link |
through ice baths or other things that increase adrenaline
link |
can raise your so-called stress threshold.
link |
But here we're talking about cellular stress
link |
and damage to cells.
link |
So my read of the literature, and again, this is my read,
link |
and I invite others to provide studies,
link |
or I would prefer actually collections of studies
link |
that point in the direction, if they exist,
link |
that alcohol can be beneficial.
link |
But my read of the literature, or I should say,
link |
my understanding of what I would call the center of mass
link |
of the literature on alcohol is that no consumption,
link |
zero consumption, consumption of zero ounces of alcohol
link |
is going to be better for your health
link |
than low to moderate consumption of alcohol.
link |
And that low to moderate consumption of alcohol
link |
is going to be better for you, of course,
link |
than moderately high to high alcohol consumption
link |
on the order of 12 to 24 or more drinks per week.
link |
I realize that for most people listening to this,
link |
it's probably low to moderate alcohol consumption
link |
that is part of their standard repertoire.
link |
And I'm not here to give you justification for doing that,
link |
nor am I going to tell you not to do that.
link |
I would like you to consider perhaps, however,
link |
the negative effects that we understand
link |
and that are documented.
link |
For instance, the negative effects of alcohol
link |
in the gut microbiome and the things that you can do
link |
to better support your gut microbiome.
link |
The negative effects on the stress system,
link |
that HPA axis that we talked about earlier,
link |
and the fact that even low to moderate levels
link |
of alcohol consumption can increase our levels of stress
link |
when we're not drinking,
link |
and to think about acquiring some tools
link |
and getting some proficiency with tools,
link |
behavioral or otherwise,
link |
that can help you with stress modulation
link |
that don't involve alcohol consumption.
link |
Again, the point here is to illustrate
link |
where the problems lie with alcohol consumption,
link |
but also what I've tried to do
link |
is to point you to some resources
link |
that can help offset some of those negative effects.
link |
Will they offset all the effects?
link |
I can't say that for sure,
link |
but certainly taking measures
link |
to offset some of the negative effects
link |
of any alcohol consumption
link |
that you might be having or doing
link |
is going to be beneficial to you.
link |
And those tools and protocols
link |
are going to be health promoting in any case.
link |
If you're learning from and or enjoying this podcast,
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please subscribe to our YouTube channel.
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That's a terrific zero cost way to support us.
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In addition, please subscribe to the podcast
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If you have questions for us
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link |
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at the beginning of today's podcast
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That's the best way to support this podcast.
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If you're not already following us on social media,
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We are Huberman Lab on Twitter,
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but much of which is unique from the content
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Again, that's Huberman Lab on Instagram
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and Huberman Lab on Twitter.
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Please also check out our neural network monthly newsletter.
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This is a newsletter that has summaries of podcast episodes.
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It also includes a lot of actionable protocols.
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I'd also like to point out
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that the Huberman Lab Podcast has a clips channel.
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So these are brief clips, anywhere from three to 10 minutes
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that encompass single concepts and actionable protocols
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related to sleep, to focus,
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interviews with various guests.
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We talk about things like caffeine,
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when to drink caffeine relative to sleep,
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alcohol, when and how,
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and if anyone should ingest it relative to sleep,
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dopamine, serotonin, mental health, physical health,
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all the things that relate to the topics
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most of interest to you.
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You can find that easily by going to YouTube,
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look for Huberman Lab Clips in the search area,
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Subscribe, and we are constantly updating those
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This is especially useful, I believe,
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for people that have missed some of the earlier episodes
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which admittedly can be rather long.
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And last, but certainly not least,
link |
thank you for your interest in science.
link |
I'll see you next time.