What Alcohol Does to Your Body, Brain & Health

Welcome to the Huberman Lab podcast where we discuss science and science based tools for everyday life. I'm Andrew Huberman and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine. Today we're discussing alcohol, one of the most commonly consumed substances on the planet Earth. I should mention that both humans and non human animals consume alcohol either for recreational purposes because they like the feeling that it gives them, or for medicinal purposes or for other purposes that we'll discuss. We are of course going to discuss the effects of alcohol on our biology, ranging from its effects on individual cells on organs and organ systems in our brain and body. We are also going to discuss the effects of the effects of alcohol, that is what being inebriated really does to our thinking and our behavior and how it does it. And we are going to address what seems to be one of the more common questions out there, which is whether or not low to moderate amounts of drinking are better for our health than zero alcohol consumption at all. And of course, we will talk about severe alcohol intake, binge drinking. We will also talk about hangover and what science says about ways to reduce the effects of hangover, either by doing things that are inoculatory, meaning before you drink or while you drink, as well as things to do if you happen to have a hangover. We will discuss some of the genetic differences for alcohol and alcoholism. And we will discuss alcohol consumption in young people and how that can be especially detrimental for reasons that I think are going to be quite surprising to most of you. My goal is that by the end of today's episode, you will have a thorough understanding of what alcohol does to your brain and body and that you will be able to make informed decisions as to whether or not you should be consuming zero, absolutely no alcohol, small to moderate amounts of alcohol. And again, we'll define exactly what that means. Small to moderate amounts. And if you or somebody else that you know is consuming excessive amounts of alcohol that are clearly detrimental to your health, some of the better routes and resources that you can use in order to remove that dependence and or consumption. I'd like to preface all of that by saying that today's discussion is really geared toward giving you information. It is not about judging alcohol intake or lack of alcohol intake. I just want you you to be able to make the most informed decision about alcohol possible. I'm pleased to announce that the Huberman Lab podcast is now partnered with Momentous Supplements. We partnered with Momentous for several important reasons. First of all, they ship internationally because we know that many of you are located outside of the United States. Second of all, and perhaps most important, the quality of their supplements is second to none, both in terms of purity and precision of the amounts of the ingredients. Third, we've really emphasized supplements that are single ingredient supplements and that are supplied in dosages that allow you to build a supplementation protocol that's optimized for cost, that's optimized for effectiveness, and that you can add things and remove things from your protocol in a way that's really systematic and scientific. If you'd like to see the supplements that we partner with Momentous on, you can go to livemomentous.com huberman there you'll see those supplements. And just keep in mind that we are constantly expanding the library of supplements available through Momentous on a regular basis. Again, that's livemomentous.com huberman before we get into today's content in detail, I just want to answer a commonly asked question about alcohol consumption and the brain. And the question that so often comes up is whether or not low to moderate amounts of alcohol, so maybe one drink a day or one or two drinks a day kind of thing, whether or not that is bad for your brain, in particular whether or not it causes degeneration of neurons or nerve cells. Now the reason that question comes up so often is because for many years it's been known that high levels of alcohol consumption, so 12 to 24 drinks per week or more, is certainly causing neurodegeneration, in particular of the so called neocortex, the outer layers of the brain that house associative memories, that house our ability to think and plan, that house our ability to regulate our more primitive drives according to context, et cetera. So to make very clear, drinking a lot, so having, you know, three or four drinks per night, every night of the week is clearly bad for the brain. A recent study, however, finally addressed the question of whether or not low to moderate amounts of alcohol consumption can cause brain degeneration. The title of the study is Associations between Alcohol Consumption and Gray and White Matter Volumes in the UK Biobank the United Kingdom Biobank first of all, gray matter are the neurons, is the so called cell bodies that would house the genome of the cells, et cetera. And white matter is the connections, the fibers, the so called axons of neurons. And it, it's called white matter because that that tissue is surrounded by a fatty tissue called myelin, which allows nerve cells to communicate with each other very quickly. So what this study did is it looked at the brains, both the gray matter and the white matter of more than 30,000, indeed more than 35,000 generally healthy middle aged and older adults in the United Kingdom who were drinking various amounts of alcohol. What they found was that even for people that were drinking low to moderate amounts of alcohol, so one or two drinks per day, there was evidence of thinning of the neocortex. So loss of neurons in the neocortex and other brain regions. And I don't say this in order to cause alarm. I tell you this because they are important data, because they reveal and indeed answer the question that has been burning for so long as whether or not chronic alcohol intake can disrupt the brain, even if the chronic intake is very low. Now we should talk about what the word chronic means, because many people, when they hear the word chronic, think high levels of whatever intake. Okay, so they think five drinks a night or 10 drinks a night, or people drinking every night. Now in this study they looked at people who on average were drinking one or two drinks per night. So, so that could be 14 drinks on the weekend. It could be one drink per night, it could be seven drinks on Friday. In other words, on average, one or two drinks per night. And I think many people out there are drinking somewhere between one and two drinks per night or day of the week on average. So that would be seven to 14 drinks per week. So this is an important study because it says that if you're consuming even just seven glasses of wine across the week, it's likely that there is going to be some degeneration of your brain in response response to that alcohol intake. Although as mentioned earlier, we will talk about some of the things that can inoculate against some of that neuronal loss. For those of you that are interested in reading the study in more detail, we put a link to it in the show. Note Captions before we begin, I'd like to emphasize that this podcast is separate from my teaching and research roles at Stanford. It is, however, part of my desire and effort to bring zero cost to consumer information about science and science related tools to the general public. In keeping with that theme, I'd like to thank the sponsors of today's podcast. Our first sponsor is levels. Levels is a program that lets you see how different foods affect your health by giving you real time feedback on your diet using a continuous glucose monitor. One of the most important features of our immediate feelings of well being and our ability to focus and think and move and have energy as well as our long term health are our blood glucose levels, that is our blood sugar levels. And that's because our all the cells and tissues of our body, and especially neurons, nerve cells, rely on glucose for fuel. I realize some of you out there are ketogenic and yes, you can use ketones for fuel, but the vast majority of people are using glucose for fuel in their cells. If you want to maintain energy and focus throughout the day, you want to keep that blood glucose steady and you don't want it ever to spike or to drop too much. So you need to understand how different foods and indeed how different activities impact your blood glucose. I started using levels about a year ago as a way to understand how different foods and exercise and supplements and combinations of food and exercise and even sequencing like when I do what, how that affects my blood glucose levels. It's been tremendously informative. It's completely reshaped when I exercise, how I exercise, when I eat, relative to exercise, et cetera. So if you're interested in learning more about levels and trying a continuous glucose monitor yourself, go to Levels Link Huberman Again, that's levels. L I N K Today's episode is also brought to us by eight Sleep. Eight Sleep makes smart mattress covers with cooling, heating and sleep tracking capacity. I've talked many times on the podcast about the fact that getting a great night's sleep is the foundation of mental health, physical health, and all forms of performance. And one of the key variables in getting a great night's sleep is making sure that your sleeping environment is the right temperature. Indeed, your brain and body have to drop by 1 to 3 degrees in order to get into sleep and to stay in deep sleep throughout the night. If your room is too hot or if you're running too warm, you will wake up. In fact, that is why you wake up in the morning with eight Sleep. You can adjust the temperature of your mattress and your overall sleeping environment and customize that to you. I started using eight Sleep some time ago and it's just been a total game changer. I program mine so that there's a subtle drop in the temperature of my mattress at the beginning of the night and then gets progressively cooler and then it heats up toward morning. Even has this nice little vibrate feature so it wakes me up by vibrating the mattress a little bit. And of course that mattress is and warming is the way that we wake up. If you'd like to try 8 Sleep, go to eightsleep.com huberman Check out their Pro Prod cover and save up to $150 at checkout. Eight Sleep currently ships in the USA, Canada and the United Kingdom. Again, that's eightsleep.com huberman to save $150 at checkout. Today's episode is also brought to us by Roka. Roka makes eyeglasses and sunglasses that are of the absolute highest quality and they also have some unique characteristics. The company was founded by two all American swimmers from Stanford and everything about Roka eyeglasses and sunglasses were designed with performance in mind. Roka eyeglasses and sunglasses can be worn while running or cycling. If you get sweaty, they won't fall off your face and they're extremely lightweight. In fact, most of the time I can't even remember that I'm wearing them. I wear Roka eyeglasses when I read at night, so I wear the readers and I wear sunglasses at various times throughout the day. The great thing about Roka eyeglasses and sunglasses is that even though they were designed for athletic performance, they have a terrific aesthetic. They so unlike a lot of so called performance glasses that make people look like cyborgs. In my opinion, Roka eyeglasses and sunglasses are the sort that you could wear out to dinner, that you could wear to work. They have a terrific aesthetic. If you'd like to try Roka eyeglasses or sunglasses, you can go to ROKA. That's R O-K A.com and enter the code HUBERMAN to save 20% off your first order. Again, that's ROKA R O K A.com and enter the code Huberman at checkout. Let's talk about alcohol and let's just acknowledge that human beings have been consuming alcohol for thousands of years. If you look at the archeological evidence from Mesopotamia, you'll find that 5,000 years ago people had wine vessels. Or if you want to know when people first started distilling alcohol, much to people's surprise, that did not first take place in Ireland. And that's not a joke about the Irish that you'll see a lot of claims online that the Irish were the first to distill alcohol, but in fact they were not. It was the Chinese that were the first to distill alcohol and that took place in China in the first century. Alcohol has been used for nutritional purposes. So there are cultures that believe and indeed still believe that the calories in alcohol are useful. Although later we'll talk about how alcohol calories are indeed empty calories and what an empty calorie really is. Why it's called empty alcohol has been used for medicinal purposes because indeed it does kill bacteria and as you'll soon find out, the fact that it kills bacteria, because that is absolutely true, it also kills the good bacteria in your gut. And the destruction of that good bacteria in your gut can lead to things like leaky gut syndrome and has all sorts of issues. And there are ways to deal with those issues, and we'll talk about those. So alcohol has been used for medicinal purposes. It's been used to clean surfaces, it's used in my laboratory in order to make up so called reagents to do our experiments. But most humans have been consuming alcohol in order to change their internal state, in order to feel differently than they would otherwise. That feeling of being drunk or inebriated or tipsy or lightheaded is something that many, not all, but many humans seem to enjoy and pursue. Even though typically it leads to a feeling of being less happy, less motivated, more stressed, et cetera, when the alcohol wears off. That's pretty incredible, right? I mean, we're talking about a substance that people have been highly motivated to pursue, that are still highly motivated to pursue, to create and to consume, that they'll spend money on. And that's despite the fact that it makes them feel good and then it makes them feel lousy. Now, some of you might be saying, well, I drink, but I don't drink to excess and therefore I don't feel lousy. I feel good when I drink, and then it wears off and allows me to get through my evening and then the next morning I'm ready to go. Okay, that very well may be true. I believe those people. And as I mentioned at the beginning of the episode, I'm not here to demonize alcohol in any way, but I do want to point out what alcohol is and how it creates the effects that it does. And then I want to talk about what those effects are when you engage in consuming alcohol even as often as one or two nights per week. Or let's say you're just somebody who has a drink or two on Friday, maybe a few more on Saturday, or maybe you're somebody, somebody who consumes all your alcohol one night per week or one night per month. We'll talk about how that's affecting your biology. So let's address what alcohol is and how it affects the cells and tissues and organs of your body. Then we'll take a look at some of the epidemiology, that is how many people are consuming alcohol and how much they're drinking. And then you'll be able, I think, to get a good sense of how the alcohol that you're drinking, if you're drinking any at all, is impacting your brain and body and the choices you might want to make about how and when to drink alcohol, or even if you want to eliminate alcohol altogether. Okay, so some basic chemistry and biology of alcohol. And again, I'll make this very clear, even if you don't have a chemistry and biology background, because of the structure of alcohol, it is what's called both water soluble and fat soluble, translated into what's meaningful for you. What that means is when you drink alcohol, it can pass into all the cells and tissues of your body. It has no trouble just passing right into those cells. So unlike a lot of substances and drugs that actually attach to the surface of cells, to receptors, as they're called, little parking spots, and then trigger a bunch of downstream, like, domino cascades of effects, alcohol actually has its own direct effects on cells because it can really just pass into those cells. So it's water and fat soluble. And the fact that it can pass into so many organs and cells so easily is really what explains its damaging effects. I should mention that there are three main types of alcohol. There's isopropyl, methyl and ethyl alcohol. And only the last one, ethyl alcohol, or ethanol, is fit for human consumption. However, it is still toxic. Okay? It produces substantial stress and damage to cells. I'd love to be able to tell you otherwise, but that's just a fact. Ethanol produces substantial damage to cells, and it does that because when you ingest ethanol, it has to be converted into something else because it is toxic to the body. And there's a molecule inside of all of us called nad. And you may have heard of NAD because it's quite popular. There's a lot of discussion about NAD in the longevity literature. Right now. NAD is present in all our cells from birth until death. The levels of NAD tend to go down across the lifespan. There are ideas that increasing levels of NAD may extend lifespan. A lot of that is still controversial, or at least we should say is ongoing in terms of the research. But nonetheless, when you ingest ethanol, NAD and related biochemical pathways are involved in converting that ethanol into something called acetyl aldehyde. It's broken down into acetaldehyde. And if you thought ethanol was bad, acetaldehyde is particularly bad. Acetaldehyde is poison. It will kill cells, it damages and kills cells, and it is indiscriminate as to which cells it damages and kills. Now, that's a problem, obviously, and the body deals with that problem by using Another component of the NAD biochemical pathway to convert AC acetaldehyde into something called acetate. Acetate is actually something that your body can use as fuel. And that process of going from ethanol to acetaldehyde to acetate does involve the production of a toxic molecule. Right? Again, acetaldehyde is really toxic and nad, and if we want to get technical, it's the NAD to NADH ratio. And that chemical step is the rate limiting step to ethanol's metabolism. What does that mean for you? What that means is that if your body can't do this conversion of ethanol to acetyl aldehyde to acetate fast enough, well, acetyl aldehyde will build up in your body and cause more damage. So it's important that your body be able to do this conversion very quickly. And the place where it does that is within the liver. And cells within the liver are very good in at this conversion process, but they are cells and they are exposed to the acetyl aldehyde in the conversion process. And so cells within the liver really take a beating in the alcohol metabolism events. So the key thing to understand here is that when you ingest alcohol, you are, yes, ingesting a poison. And that poison is converted into an even worse poison in your body. And some percentage of that worst poison is converted into a form of calories that you can use to generate energy, generate ATP. And the reason why alcohol is considered empty calories is because that entire process is very metabolically costly, but there's no real nutritive value of the calories that it creates. You can use it for immediate energy, but it can't be stored in any kind of meaningful or beneficial way. It doesn't provide any vitamins, it doesn't provide any amino acids, it doesn't provide any fatty acids. It's truly empty calories. I know some people talk about sugar as empty calories, but sugar actually is a far better fuel source than alcohol or acetate. But nonetheless, when you ingest alcohol, some percentage is being shuttled into a worse poison and some is being shuttled into a fuel source. Now the important thing to understand is that it is the poison, the acetaldehyde itself, that leads to the effect of being inebriated or drunk. I think most people don't realize that, that being drunk is actually a poison induced disruption in, in the way that your neural circuits work. And so we should ask ourselves like which neural circuits, what brain areas, what body areas involved in feeling drunk or inebriated? Now, in thinking about this state of being tipsy or happy or really drunk or a little bit drunk. I want to mention something I think most people aren't aware of, and that's the fact that for people that are regular drinkers or that have a genetic predisposition to alcoholism, when they drink, they tend to feel very energized and very good for longer periods of time. Again, people have a genetic predisposition to alcohol or people who are chronic drinkers, or even just if you recall, chronic doesn't have to mean a ton of alcohol, but they're drinking one or two per night, or they're every other night type drinkers or Thursday through Sunday drinkers. Those people typically experience an increase in alertness and mood when they drink, Whereas occasional drinkers will have a briefer, meaning less long lasting period of feeling good when they drink and then more quickly transition into a state in which they're tired or they start losing motor skills, they start slurring their speech. I also want to emphasize this is distinct from tolerance. We'll talk about tolerance later and exactly what tolerance means. But I really want to highlight the fact that when people ingest this poison, because indeed it is poison, the range of effects is very different. And you can reliably predict who are the people with a predisposition to alcoholism and who are the people who are more regular drinkers by the contour, the timing of the different effects. And again, people who tend to feel more alert and excited every time they drink, they tend to get a real lift. They become kind of the life of the party and that lasts a long while. Those people are the ones that really have to be careful about predisposition for alcoholism. And those people also need to be careful about their drinking and the amount of drinking that they're doing, even if they're not full blown alcoholics. Now, of course, people who are ingesting alcohol, who are not accustomed to drinking alcohol have to be concerned about drinking alcohol for other reasons because it can impair motor function and judgment, et cetera. But in thinking about the biochemical effects of alcohol and what it's doing to the body, what it's doing in all cases is it's consumed into the gut, right? Goes into the stomach. The liver immediately starts this conversion that we talked about before of ethanol to acetaldehyde to acetate, and some amount of acetaldehyde and acetate are making it into the brain. It crosses the blood brain barrier. Again, the brain has this fence around it that we call the blood brain barrier or the bbb. Many things Most things, thankfully, can't pass across the blood brain barrier, but alcohol, because it's water and fat soluble, just cruises right across this fence and into the milie, the environment of the brain, which is made up of a couple different major cell types, neurons, nerve cells, and so called glial cells, which are in between the nerve cells. And we'll talk about the effects on each of those soon. So what happens when alcohol gets into the brain that makes us feel tipsy or drunk, and in some people, makes people feel really especially energized and happy? Well, alcohol is indiscriminate in terms of which brain areas it goes to. Again, it doesn't bind to particular receptors, but it does seem to have a propensity or an affinity for particular brain areas that are involved in certain kinds of thinking and behavior. So one of the first things that happens is that there's a slight, at least after the first drink or second drink, there's a slight suppression in the activity of neurons in the prefrontal cortex. This is an area of your neocortex that's involved in thinking and planning, and perhaps above all, in suppression of impulsive behavior. So if you go to a party and they're serving alcohol and people are consuming drinks, what you'll notice is that a few minutes into that party, the volume of people's voices will increase. And that's because people are simply not paying attention to their voice modulation. As other people start speaking more loudly, other people are speaking more loudly. We've all had this experience, right, of going to a party, and then you step outside for a moment and you go, oh my goodness, I was shouting. You come home the next day, you got a sore throat, might be that you picked up some sort of bug, some virus or something. But oftentimes it's just the fact you've been shouting all night just to be heard. Because as the prefrontal cortex shuts down, people stop modulating their level of speech quite as much. Also notice that people start gesticulating more. People start standing up and sitting down more, they'll start walking around more. If there's music on, people might spontaneously start dancing. All of this is because these areas of the prefrontal cortex normally are providing what's called top down inhibition. They are releasing a neurotransmitter called GABA onto various parts of the brain. They're involved in impulsive motor behavior and thought patterns. And, and as you shut down the prefrontal cortex, that GABAergic suppression of impulses starts to be Released. So people will say things that they want to say without so much forethought about what they're saying. Or they might do things that they want to do without really thinking it through quite as much. Or they might not even remember thinking it through at all. Or experience, I should say, thinking it through at all. We haven't talked about blacking out yet and the effects of alcohol on memory. But as long as we're there, I'll just tell you that alcohol has a very strong effect in suppressing the neural networks that are involved in memory formation and storage. This is why oftentimes we forget the events of a night out if we've been drinking. One of the more important things to know about the effects of alcohol in the brain is this disruption in top down inhibition. But also that areas of the brain that are involved in flexible behavior, sort of considering different options, like I could do A, or I could do B. I could say this to them, or I could say that I could say it in that way, or I could say it in this way. This might be a little more tactful. Those brain areas basically shut down entirely. And people just tend to say what they want to say. So the key thing to understand is that when people drink, the prefrontal cortex and top down inhibition is diminished. That is habitual behavior and impulsive behavior starts to increase. Now, what's interesting is this is true in the short term. So after people have one or two, maybe three or four drinks. But it's also true that the more often that people drink, there are changes in the very circuits that underlie habitual and impulsive behavior. This is really important to highlight. So much so that I want to drill into it a little bit more deeply for the person that drinks, say, every Thursday night or every Friday night, or goes out only on Saturdays, but every Saturday. There's evidence that there are changes in the neural circuits of the brain that control habitual behavior and impulsive behavior. And they are modified and strengthened in ways that make those people more habitual and more impulsive outside the times in which they are drinking. And when they drink, impulsive and habitual behavior tends to increase even further. This is something that's not often talked about when discussing the effects of alcohol. And we all know the effects of being drunk can be bad, right? Can be bad in terms of judgment, motor coordination. Certainly driving drunk is a terrible thing, get you or other people killed and so on. But rarely do we hear about the changes in neural circuits from just one or two nights of regular drinking. Again, chronic drinking doesn't necessarily mean every day and every night. It could be the person that simply drinks every Thursday or every Friday, or just once a week, has three or four drinks or maybe even a few more, that person is going to experience a decrease in this top down inhibition. So an increase in impulsivity and habitual behavior because the brake on those behaviors has been removed while they're drinking. But also changes in the very neural circuits that allow habitual and impulsive behavior to occur more readily, even when they're not drinking. And if you want to know the actual substrate for that, the cellular substrate, I can briefly describe it. It's really interesting. Again, you don't need to know any biology to understand this. What it does is it increases the number of synapses, the actual points of connection in the neural circuits that control habitual behavior. So there's literally a growth of the neural circuits in your brain that lead to existing habit execution. Right? The performance of things you already know how to do, and a reduction in the neural circuits, or I should say a reduction in the number of synapses of the contacts within the neural circuits that are controlling behavior. So this again is a not often discussed aspect of alcohol intake. Fortunately, it is reversible. So in animals or humans that undertake a period of abstinence of anywhere from two to six months, these neural circuits return to normal. Except in cases where people have been chronically drinking large volumes of alcohol for many, many years. And in those cases, while there is some recovery of brain circuitry, after people get sober, meaning completely sober, they stop drinking entirely. There is evidence of long lasting impact of heavy alcohol usage throughout the lifespan. But of course, this doesn't mean that anyone that's suffering from alcoholism or that used to should not continue to focus on their health. You absolutely should. All is not lost. But for people that have been drinking for a lot of years, maybe you went to college and you drank a lot in those years and your neural circuits change. If there's a period in which you don't drink alcohol again, from two to six months, and ideally longer, those neural circuits can then be remodified back to their original state. So let's consider some of the other neurochemical effects of alcohol in the brain and body. And again, for right now, we're confining the conversation to people that are drinking on average one or two drinks per night. Now, some people might think that two drinks per night is a lot, and a lot of that will depend on body weight. So for instance, people who weigh 110 pounds. For them to ingest two alcoholic drinks is going to be substantially different in terms of the biochemical effects than somebody who weighs 220 pounds. Of course, tolerance will also factor into this. Genetic background will also factor into this. And indeed, whether or not people have eaten will factor into this. So there are a lot of factors, and we'll talk about that for the time being. If you're curious about how food impacts the effects of alcohol and your feelings of being drunk, you may have heard, for instance, that if somebody's inebriated and they want to sober up, they should eat something. Turns out that does not work. Here's how it does work, however. If you eat something prior to drinking alcohol or while ingesting alcohol, it will slow the absorption of alcohol into the bloodstream. In other words, you won't feel as drunk as fast. For many of you, this probably comes as no surprise in particular if that meal includes carbohydrates, fats and proteins. Okay. The inclusion of all three major macronutrients seems to slow the absorption of alcohol into the bloodstream far more than any than having any one of those or two of those macronutrients present. Now, if you are already inebriated or you've had a glass of wine or a beer and you eat something, chances are that alcohol has already made it into your bloodstream because it moves into the bloodstream so quickly. Again, it's fat soluble and water soluble. So within minutes, right? If you're on, if you have an empty stomach, within five to 10 minutes, that alcohol is going to be within your bloodstream and distributed throughout your body, maybe even faster, depending on the type of alcohol and your metabolism. But if you're already drunk and you eat something, it's not going to sober you up more quickly, but it certainly will blunt the effects of any additional alcohol that you might consume. And if you're somebody who is concerned about getting too drunk too quick, even from a small amount of alcohol, having some food in your gut can certainly be beneficial. Now, that's food and alcohol and the absorption of alcohol. But let's go back to talking about the biochemical and neurochemical effects of alcohol on the brain. We talked about top down inhibition and we talked about habitual and impulsive behavior. Circuitry. There are also dramatic changes in the activity of neurons that control the release of so called serotonin. Serotonin is a neuromodulator. It changes the activity of neural circuits and many neural circuits, in particular, those involved in mood and feelings. Of well being. Recently there's been a lot of interest in serotonin because of a study that was released that showed pretty conclusively that serotonin levels can't really explain depression and depression like symptoms. I want to make it very clear that although that study did show that serotonin levels are not necessarily associated with depression, the study was interpreted by many to mean that SSRI selective serotonin reuptake inhibitors, which have the net effect of increasing serotonin. So these are things like Prozac, et cetera, that those drugs are somehow not helpful because they increase serotonin and serotonin isn't involved in depression. That logic doesn't really hold together. So I'm going to use this as an opportunity to just clarify what really occurred there and then we'll talk about how serotonin relates to alcohol consumption in things like feeling good and in depression. The key thing is this SSRIs can help alleviate depression. That's right, SSRIs can help alleviate depression. They are often not always associated with side effects, dosage is very important, etc. But they probably support relief from depression by changing neural circuits, not necessarily by increasing serotonin itself. That is, increasing serotonin with these drugs likely change the neural circuits involved in mood, allowing people to feel better through so called neuroplasticity, which is the brain's ability to change itself in response to experience. So there's a bit of confusion and again, I'm using this episode on on alcohol to highlight some of the confusion because I think it's timely because the study just came out and there's a lot of chatter about this out there that when people are depressed it's not necessarily because serotonin levels are low. However, if serotonin levels are increased with things like Prozac, Zoloft and other SSRIs, oftentimes there is, yes, a relief from depression, but that's probably not because of restoring serotonin levels per se. It's probably because serotonin facilitates the changes in neural circuits that need to occur in order for people to feel elevated mood. Okay, so again, that's a bit of a tangent and aside, but I do think it's a vital one for people to know about. Again, if you're thinking about taking SSRIs, you're currently taking them and you've heard this news, definitely talk to your doctor. Again, there is great utility for some of these SSRIs and also in conditions like OCD, they've been shown to be very beneficial. So we really don't want to throw SSRIs out as a potentially valuable treatment. Getting back to the effects of alcohol on serotonin, it's very clear beyond any doubt that many of the circuits in the brain that are involved in mood and feelings of well being and also sort of self image in how we see ourselves employ the neuromodulator serotonin and alcohol, when we ingest it and it's converted into acetyl aldehyde, it goes. And that acetyl aldehyde acts as a toxin at the very synapses, the connections between the serotonergic neurons and lots of other neurons. In other words, when we ingest alcohol, the toxic effects of alcohol disrupt those mood circuitries at first. Making them hyperactive. That's right, making them hyperactive. This is why people become really talkative. People start to feel really good after a few sips of alcohol. At least most people do. And then as they congest more alcohol or as that alcohol wears off, serotonin levels and the activity of those circuits really starts to drop. And that's why people feel less good. And typically what they do, they go and get another drink and they attempt to kind of restore that feeling of well being and mood. Now, typically what happens is that as people ingest the third and fourth, maybe even the fifth drink, there's an absolute zero chance of them recovering that energized mood. Right. Most people, as they drink more and more, will now start to feel more and more suppressed. The forebrain is now shutting down quite a lot. A lot of the motor cortical areas that control coordinated movement and deliberate movement start to shut down. So people start to slur their speech, people start to shuffle their feet, people forget their posture, people start to lean on things, people start passing out on couches. There's a great depression, not depression of the psychiatric depression sort, but a depression of alertness and arousal. And eventually people will pass out. Now, I said most people because there's a subset of people that have gene variants or who are chronic drinkers or who are chronic drinkers and have gene variants that as they ingest the third and fourth and fifth drink, what happens? They become more alert, they start talking more, they feel great, they have all sorts of ideas about the fun they could have that night. And they're the ones that, that if you've ever fallen asleep at a party for whatever reason, or you're getting tired and you're yawning, you're looking around the room and like these people are still drinking and partying, and they're having what seems to be this amazing time. Often, not always. Those are the future alcoholics in the room, or those are the people that have a genetic predisposition for alcoholism, or those are the chronic drinkers, the people who have built up enough of a tolerance.