How Alcohol Impacts Your Body and Brain

You might have heard — and this is something that I heard when I was younger and growing up — that one drink a day is good for you; this was believed for a very long time, and I’m French and let me tell you most French people still believe that. It’s not their fault — they just don’t know the latest science, and a lot of doctors don’t either — so let’s talk about that.

Hello angels, and welcome back to the Glucose Goddess Show; I’m your host Jessie Inchauspé, a French biochemist, and I love explaining science in a really fun way so that you can understand how your body functions.

Today we’re talking about alcohol — a very highly requested topic. When I give any conference or talk, inevitably someone asks about alcohol, so I’m going to show you the science behind it: what it does to our body and brain; whether it’s true that one drink a day is good for our health; we’re going to bust some myths, have a good time, and you’re going to learn a lot.

First, if you’ve ever worn a continuous glucose monitor and you drink alcohol, you may have noticed a strange pattern: pasta on its own gives a big glucose spike, but if you add, as in this graph, a glass of red wine to the pasta, suddenly you get a smaller spike. What does this mean — should we add wine to meals to reduce spikes because smaller spikes are better for us? No. I’ll explain, but the answer is not to add wine to every meal. Rewind: a drink of alcohol — wine, vodka, beer — is mostly water (about 80–90%), then ethanol (very important molecule), then flavor compounds; in some sweet wines you’ll also have high sugar. Ethanol is the molecule with effects on our body. It’s produced when yeast ferments sugars in grapes or other plants; fun fact: there are ~10^23 ethanol molecules in one glass of wine — as many molecules as stars in the universe. Typical ethanol percentages: beer 1–6%, wine 12–14%, fortified wines like sherry/port 18–20%, spirits (vodka, rum, gin) 40–50%.

Time for a quick break to tell you about the supplements I have developed: Anti-Spike Formula. In my years of research I’ve understood one key thing — keeping our glucose levels steady is the foundation of physical and mental health — and if I could only take one supplement for the rest of my life to help reduce glucose spikes and keep levels steady, it would be Anti-Spike. I created Anti-Spike with two powerful natural plant molecules: first, mulberry leaf extract; in a review of 12 randomized clinical trials on 600+ people, scientists found it significantly reduces post-meal glucose spikes by up to 40%, insulin spikes by up to 40%, and fasting glucose by 8 mg/dL after two months — it reduces glucose absorption and slows starch-to-glucose conversion, massively reducing meal spikes. Second, a lemon molecule called eriocitrin — the pigment that makes lemons yellow — which helps the gut produce more GLP-1; clinical trials show GLP-1 increases by 17% after two months; more GLP-1 means healthier glucose levels. I take two capsules every day before my highest-carb meal. Go to anti-spike.com to see the science, read thousands of testimonials, and order your own bottle.

So what happens when we drink ethanol? It goes to the stomach and upper intestine, then into the bloodstream, and is recognized by the body as a toxin. The liver — our filtration system — gets tasked with clearing it, which is why alcohol can be linked to liver problems. The liver “cuts the box into pieces”: ethanol → acetaldehyde (the smell you notice on heavy drinkers), which is also very toxic; then acetaldehyde → acetic acid (the main acid in vinegar), which is safe. But this breakdown takes time. In a study (“Cytokine changes following acute ethanol intoxication in healthy men: a crossover study”), young males drank 300 mL of pure vodka on an empty stomach in 30 minutes; it took around five to six hours for the body to eliminate just half the ethanol. While clearing ethanol, the body is exposed to ethanol and acetaldehyde for hours.

Back to the pasta-plus-wine graph: the liver also regulates blood glucose. When you drink, your liver is busy detoxifying ethanol and can’t manage glucose as effectively; the spike looks smaller because your liver is preoccupied with a poison. That is not a reason to add wine to pasta. If you want to manage glucose — the foundation of physical and mental health — use my 10 glucose hacks (food-based, not alcohol-based). What damage occurs as ethanol and acetaldehyde circulate? In the gut, ethanol damages the cells lining your stomach and intestines, impairing nutrient absorption (common deficiencies in heavy drinkers), promoting leaky gut and IBS, and killing good bacteria (alcohol disinfects — like bacteria). Ethanol crosses the blood–brain barrier and triggers dopamine (pleasure/reward) and serotonin (calm/happiness); some people release more than others, which explains euphoria for some and greater risk of heavy use. After the “high,” suppression kicks in: ethanol and acetaldehyde damage neurons, especially those managing impulse control, judgment, motor coordination, and memory formation — hence poor coordination and blackouts. Habitual use lowers baseline mood; you feel worse on non-drinking days and become more dependent to feel “normal.” A paper (“Effect of alcohol on the central nervous system to develop neurological disorder”) details how alcohol creates DNA damage in neurons, errors accumulate, and dysfunction increases; alcohol accelerates brain aging, kills existing neurons, and impairs neurogenesis, affecting cognition, memory, and spatial awareness — like a very slow, very gradual “stroke.” Three drinks a day is clearly damaging; that’s long been known.

But what about one drink a day? Many of us heard it was “good for you,” based on associative studies showing one-drink-a-day people looked healthier than zero-drinkers; those analyses were deeply flawed. Major confounders: former heavy drinkers who quit for health reasons got lumped into the zero-drinks group (sicker baseline), and many healthy older people with no chronic disease kept having one drink, so the drink was a consequence of good health, not the cause.

Two important 2022 studies changed the game. First, “Associations between alcohol consumption and gray and white matter volumes in the UK Biobank” (≈40,000 people) showed that even one drink a day is associated with brain shrinkage, neuron death, cognitive decline, and cortical thinning — i.e., accelerated brain aging. Second, “Association of habitual alcohol intake with risk of cardiovascular disease” showed that when confounders are properly removed, the supposed heart benefits disappear. Bottom line: the “one drink a day is good for you” claim is not true; even light drinking damages the brain.

If you’re genetically predisposed to Alzheimer’s, heavy drinking increases risk; if there’s cognitive decline in your family, it’s wise to cut back.

Alcohol also harms sleep (less deep/restorative sleep; the brain’s nightly toxin-clearance is impaired), raises inflammation, weakens immune function (worsening psoriasis, eczema, arthritis, autoimmunity), and increases cancer risk: alcohol is a Group 1 carcinogen (IARC), alongside asbestos, radiation, tobacco; it causes DNA mutations, and breast-cancer risk is clearly elevated even at one drink a day (“Alcohol use and breast cancer: a critical review”).

Fertility/hormones: in females, more PMS, lower fertility, higher testosterone and imbalances; in males, lower sperm quality and hormonal effects. Hangovers remain partly mysterious (dehydration, inflammation, hormone alterations, vascular dilation/constriction), but we do know a few practical things: ideally we’d help the liver process ethanol faster to reduce exposure time to ethanol/acetaldehyde.

Never take acetaminophen (Tylenol) after drinking — it slows ethanol metabolism and increases liver strain. Interesting but not a recommendation: fructose can speed ethanol processing by the liver; however, adding sugar to drinks causes its own harms (glucose spikes, additional liver load).

If choosing alcohol, prefer options without added sugar (wine, beer, or spirits with soda water) rather than sugary cocktails, so you’re not giving the liver both ethanol and sugar at once.

Practical tips from recent research: pace yourself (about one drink per hour is far better than multiple shots in minutes); eat before drinking (a veggie starter slows ethanol absorption and eases liver load); exercise regularly (a 2017 study shows exercise attenuates alcohol’s adverse effects, including on cancer risk); drink far from bedtime (protect sleep); eat fermented foods like kimchi to help replenish beneficial gut bacteria; and the morning after, choose a savory, high-protein breakfast (not carby/sugary) to avoid additional glucose spikes and metabolic stress.

As I reviewed all this research, I was surprised by how many systems alcohol affects; it makes me wonder why we treat alcohol differently from cigarettes despite comparable levels of population harm.

Draw your own conclusions, but at least now you have the data: alcohol is a toxin; it boosts dopamine and serotonin (so it feels good), and the rest is up to you.

Lots of love — I’ll see you next time.