Podcast: Does Alcohol Change Your Brain?

Courtney: Welcome to Health Matters, your biweekly dose of the latest in health and wellness from NewYork-Presbyterian. I'm Courtney Allison. This season on Health Matters, we're covering your health from A to Z, asking our experts to break down the health topics and wellness trends we're all curious about. Today, it's B, brain health. Specifically, we're examining how alcohol changes the brain. To help us break down this topic, we talked to Dr. Hugh Cahill, a neurologist at NewYork-Presbyterian, The One and Columbia. He explains how alcohol impacts our neurotransmitters, making us feel less inhibited in the short term, while increasing risk for conditions like memory disorders and stroke long term. He also shares the steps we can take to protect our brain health as we age. 

Courtney: Dr. Cahill, thank you so much for joining us today. 

Dr. Cahill: My pleasure. Thank you for having me. 

Courtney: We're here today to talk about the impact of alcohol on brain health, and I have to say, researching this episode was really eye-opening. And before we dive into what the science tells us about the longer-term effects, can you share a bit about the short-term effects? What happens in the brain when you drink alcohol, and why do we feel that buzz? You know, I think the buzz is partially why alcohol might be hard to give up as part of our social experiences. 

Dr. Cahill: Absolutely. Alcohol has many effects on the brain. It hits on different receptors in the brain, and each one of those receptors results in different sensations, including the sensation of buzz or relaxation or reduced anxiety, that endorphin feeling that we get when we drink alcohol. 

Courtney: So those feel-good feelings? 

Dr. Cahill: Yeah, that feel-good euphoria and buzz. 

Courtney: Yeah. So how does alcohol interact with neurotransmitters? 

Dr. Cahill: So the main excitatory neurotransmission in the brain occurs through glutamate receptors, including NMDA and AMPA receptors. One of the things that alcohol does as kind of a part of the buzz and some of the other effects of alcohol is, by blocking NMDA receptors, it kind of reduces the excitation of the brain, disrupts memory encoding, and affects movement and coordination. Those are different receptors that are affected when alcohol binds to the receptors in the brain. 

Courtney; So is that why we might see someone get a little clumsy or slur their words? 

Dr. Cahill: Yeah, so the receptors are located at different parts of the brain, and so when alcohol binds to the GABA receptors in the cerebellum, we have sometimes slurred speech and incoordination issues. 

Courtney: What is the research telling us about the impact of alcohol on brain health long term? 

Dr. Cahill: It was very well known that very chronic or binge drinkers, heavy alcohol use led to increased mortality. And when they compared people who were drinking very heavily with low or moderate alcohol use, there was clear association between the more you drank, the earlier you died. The one thing that kind of stuck out a little bit, though, is when they looked at cardiovascular risk factors and were comparing low or moderate use versus no alcohol use, there seemed to be a very, very mild benefit of low alcohol use in those different demographics. When it comes to the brain, though, those correlations don't seem to hold true. And when we look at things like atrophy or brain changes that we typically see, there doesn't seem to be that benefit of the low alcohol group, the mortality benefit, or the neuropathology benefit. Even in the low or moderate group, the neuropathological changes are higher than when people don't drink at all, and it gets worse the more you drink. 

Courtney: Yeah, it makes you think twice about that glass of wine with dinner. 

Dr. Cahill: Exactly. 

Courtney: And so you mentioned atrophy, 'cause something that I thought was really interesting in the research, it seems to show that alcohol affects brain volume. Can alcohol cause our brain to atrophy, to shrink? Is that right? 

Dr. Cahill: Absolutely. So part of the damage is thought to be a neurotoxic effect of alcohol. And so getting back to the basic biology of alcohol, alcohol is broken down into acetaldehyde, which is, you know, a carcinogen and a metabolic toxin, and that can cause metabolic damage of the mitochondria and cell death. And there's also effects on the GI tract in terms of vitamin absorption, which has long-term effects on the brain. So things like thiamine and B12 are very important for brain health. When a neuron dies, it's really hard to recover from neuron death. While there's still neurons being born, the brain is very sensitive to metabolic changes, and those metabolic changes accumulate through our lifetime. And so, a lot of studies have looked at not only, you know, how many drinks you have per day, but also they look at people who've had a previous alcohol-use disorder who have stopped. Those individuals still have brain health issues, even long term after they stop drinking alcohol. So there's certainly an accumulative effect over your lifetime. 

Courtney: Is there anything you could do to reverse some of the potential damage if you stop drinking or try to adopt different habits? I mean, 'cause cell death, that sounds very final. 

Dr. Cahill: Exactly. So conventional wisdom in neurology is, a long time ago, it used to be there's no neurogenesis going on in the adult brain, but that's not exactly true. I mean, outside the ventricular system, there's new neurons being born throughout our lifetime, even in older age, and that's seems to be a process that's driven a lot by exercise, actually.

Courtney; Oh, wow! 

Dr. Cahill: And so the more you exercise, the healthier your long-term brain health is. And so, yeah, there are things you can do to help keep your brain healthy over time, and much more so than word games or Sudoku is exercise.

Courtney: That's amazing, and I want to come back to the benefits of exercise later in our conversation, but before we explore that more, I wanted to ask you about the impact of alcohol on our mental health. Could you touch on how alcohol might put people at risk for conditions like anxiety or depression? 

Dr. Cahill: Absolutely. So time is an important factor in the effect of alcohol on our brain and its contribution to mood and anxiety over time. Enjoying that glass of wine with friends is a very pleasurable event. 

Courtney: Yeah. 

Dr. Cahill: It activates reward centers and releases dopamine and endorphins and makes us feel good, and in some ways, it's, in the short term at least, it's a very pleasurable thing that reduces anxiety, increases social interactions, and yet at the same time, when you have longer-term alcohol use, there are changes in the brain that occur through long-term alcohol use in mood changes that, uh, reduce the amount of pleasure we have long term and contribute to mood disorders and exacerbate underlying mood disorders. 

Courtney: Another common condition that I know many people are concerned about as they age is dementia. Do we know if consuming alcohol is a risk factor for dementia? 

Dr. Cahill: Certainly, alcohol itself is a neurotoxin and results in atrophy and shrinkage of the brain, and in and of itself can cause a vascular-type dementia in which the brain shrinks down and, and the primary symptom that people have is a memory issue. There are other dementia-like mimics, specifically Korsakoff syndrome and vitamin B1 or thiamine deficiencies, that replicate a lot of the memory issues of dementia but are caused by thiamine deficiency, which is one of the vitamins that's important in brain health. And then if you add alcohol plus another neurocognitive condition like a Alzheimer's disease or Lewy body dementia, it's another variable that quickens how fast people have progression of symptoms. 

Courtney: I was also reading it seemed like it had a negative effect on the blood vessels in the brain- 

Dr. Cahill: Yeah.

Courtney: ... like it made them stiffer, and that also caused problems? 

Dr. Cahill: Yeah, so one of the findings in strokes, when they were looking at individuals who had what we call lacunar strokes, which are small strokes within the brain, when they looked at the pathology in the regions of strokes, what they saw was that the blood vessels kind of got thicker in the area of the stroke, and that thickness is thought to be related to vascular risk factors like high blood pressure, high cholesterol, drinking alcohol. And so what many studies have shown is there'sa neuropathology, meaning even at small volumes of alcohol or mild or modest levels of alcohol, we see pathological changes, including neurofibrillary tangles and plaques and brain atrophy. So controlling cardiovascular risk factors like high blood pressure, not smoking, that reduces those pathological changes, and reducing alcohol also reduces those things, too. 

Courtney: You know, at the risk of being a little glib, I just... You know, I remember in college, friends joking around like, "Oh, I hope I didn't kill a brain cell last night." 

Dr. Cahill: Yeah. 

Courtney: And doing this research, I'm like, "Oh, my gosh, stop joking around about it!" 

Dr. Cahill: Yeah. 

Courtney: Like- 

Dr. Cahill: Yeah, yeah.

Courtney: ... you're saying the neurons, that this is not good. 

Dr. Cahill: Yeah, I think the cumulative effects, you have a couple drinks in college, and you don't think of kind of longer-term effects of those things, and I think the studies are showing that these kind of brain changes are occurring. 

Courtney: We've covered a lot about the negative effects of alcohol on the brain. We're all sufficiently bummed out. 

Dr. Cahill: Yeah. 

Courtney: But let's spend a little time talking about some of the positive and some of the things we can do for our brain health. I'd love to hear, what are some concerns you hear from patients about brain health, and what are some tips you offer themto protect their brain health? 

Dr. Cahill: Yeah, I think a lot of patients I see nowadays have either had a family friend or a loved one or a parent who've been diagnosed with a neurocognitive disorder, and, and they do show up in clinic and ask those questions. And they'reasymptomatic individuals, meaning they're not having any memory issues currently, but they have a strong family history of dementias. They're looking for the things that they can modify now. And so what are the types of recommendations? You know, the heart-healthy diet is a part of that. Exercise is a huge part of that, too, and so exercising three to five days a week, at least an hour a day, getting that heart rate up, increasing the VO2 max, those types of things are very almost universal recommendations. The brain only works on glucose, and there's such a metabolic role in terms of how those influence brain health that keeping blood pressure well controlled, keeping cholesterol well controlled, those are always a part of recommendations. In terms of brain health, we often talk about vitamin deficiencies, B1 and B12. We talk about genetic risk factors for brain health, specifically ApoE, which is a risk factor for developing Alzheimer's dementia. And so exercise, vitamins, cardiovascular risk factors, controlling blood pressure, reducing alcohol intake, controlling cholesterol, those are all very important for brain health. 

Courtney: I think you touched on this a little bit, but can activities like puzzles, reading, really help keep the brain sharp, or is the jury still out on that? 

Dr. Cahill: Yeah, the jury's still out on that. It certainly hasn't shown to slow or change any of these neurocognitive conditions, and so while there are behavioral things that I do recommend to cognitive patients, puzzles is not one of them. Sudoku is not one of them. Um, what are the behavioral things? I mean, keeping a calendar. What I tell patients, with or without a neurocognitive condition, having a schedule, keeping a calendar, putting your keys in the same place, these are the things that help you get through your day and increase quality of life. I mean, if you enjoy puzzles, go for it. They're fun to do, but they don't, they don't change neurocognitive conditions, and there's very limited evidence that those things help. 

Courtney: All right, so I can enjoy my crossword, but it might not be helping my brain health like I hope it would. 

Dr. Cahill: Yeah. 

Courtney: So we've covered a lot today about the effects of alcohol on our brain and things we can do for our brain health. What's your takeaway message, and what's your top advice for people who are maybe motivated to reduce alcohol consumption after listening to our episode, you know, to improve their health? 

Dr. Cahill: Yeah, my main takeaway would be life is long, and effects of these things are cumulative, and so, uh, keep in mind that limiting alcohol to a modest, even zero amount is probably a good thing over the lifetime and certainly would help with brain function and cognitive function long term. And you pair that with other modifiable things like exercise and improved sleep and controlling other cardiovascular risk factors, you're giving yourself the best opportunity to live a high quality of life, to have very meaningful relationships with your family and friends, and to keep your cognitive function going so that you can enjoy your hobbies and enjoy your life. I think there are certainly things that you can do, including reducing alcohol intake, that will produce a long-term benefit in terms of brain health. 

Courtney: Thank you so much. This was really, really terrific. I appreciate how you broke it all down. Thank you. 

Dr. Cahill: Yeah, thank you for including me in this conversation. It's a great topic to discuss, especially around Dry January. I think a question on a lot of people's minds. 

Courtney: Our many thanks to Dr. Hugh Cahill. I'm Courtney Allison. To learn more about Dr. Cahill's work with patients, check out the show notes. Join us next time on Health Matters when we discuss the trend of cozy cardio exercise and how to make low-impact workouts count toward our exercise and heart health goals. That's in two weeks right here on Health Matters. Health Matters is a production of NewYork-Presbyterian. The views shared on this podcast solely reflect the expertiseand experience of our guests. NewYork-Presbyterian is here to help you stay amazing at every stage of your life. To get the latest episodes of Health Matters, be sure to follow and subscribe on Apple Podcasts, Spotify, or wherever you get podcasts.