What Alcohol Does to Your Body, Brain & Health
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- ~4 min
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- 22 Aug 2022
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- 2:01:02
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KEYPOINTS
- 01
Even one to two drinks a day is linked to brain thinning
Heavy drinking (about 12–24 or more drinks a week) has long been known to degenerate the neocortex. A UK Biobank study of more than 35,000 healthy middle-aged and older adults found that an average of one to two drinks a day was also associated with thinning of the neocortex and other regions. Huberman stresses that 'chronic' refers to the pattern, so 14 drinks packed into a weekend counts too.
- 02
Alcohol is a toxin your liver converts into a worse toxin
Ethanol is both water- and fat-soluble, so it enters every cell directly. NAD-dependent steps convert it into acetaldehyde, which damages and kills cells indiscriminately, and then into acetate, which can be burned for fuel. The NAD-to-NADH step limits the rate, so when it falls behind, acetaldehyde builds up and liver cells take the hit. That is why alcohol counts as 'empty calories'.
- 03
Drinking removes top-down inhibition, and regular drinking rewires habit circuits
Alcohol suppresses the prefrontal brake on impulsive behavior while you are drunk. Even a once-a-week pattern of three or four drinks adds synapses in circuits for habitual behavior and removes them in circuits that control behavior, so people become more impulsive when sober too. Two to six months of abstinence generally reverses this, though years of heavy drinking leave lasting effects.
- 04
The serotonin lift is brief, and the next drinks can't bring it back
Acetaldehyde first makes serotonergic mood circuits hyperactive, which explains early talkativeness and well-being. Activity then drops, prompting another drink. By the third to fifth drink there is essentially no chance of recovering the high. Instead the forebrain and motor areas shut down, causing slurring, shuffling and eventually passing out.
- 05
Regular drinkers have higher cortisol even when sober
One drink a night, or two to four on weekends, shifts the hypothalamic–pituitary–adrenal axis toward more baseline cortisol, which lowers stress thresholds. This also explains 'hangxiety'. Huberman notes that people cutting back should expect a temporary rise in anxiety while the axis readjusts.
- 06
Genes and starting age shape the risk of alcoholism
Risk genes cluster in serotonin, GABA and HPA-axis pathways and interact with environment, trauma and social pressure. People with little alcohol dehydrogenase flush and feel sick, which tends to protect them. A warning sign is being able to drink all night with increasing energy, especially with blackouts. Starting young greatly raises dependence risk even without a family history.
- 07
Alcohol damages the gut–liver–brain axis in a way that drives more drinking
It kills beneficial gut bacteria and makes the gut leaky, so bacteria move into the bloodstream. Meanwhile the liver releases pro-inflammatory cytokines. These signals reach the brain and promote further drinking, a vicious cycle that is especially strong in alcohol use disorder.
- 08
Cancer risk rises with every daily drink, especially breast cancer
Each 10 g of alcohol a day, about one drink, raises cancer risk by roughly 4–13% depending on the study. A weekend total that averages to that counts the same. Alcohol both promotes tumor growth and suppresses anti-inflammatory and immune defenses. The association has been documented since a landmark 1987 paper.
- 09
Alcohol shifts testosterone toward estrogen
A 2000 review in the journal Alcohol describes alcohol's metabolites increasing aromatization of androgens to estrogens in the ovary, placenta, liver, testes and other tissues. In women this may be part of why estrogen-related cancers rise. Huberman notes that estrogen should never be driven too low in either sex, because it supports cognition and joints.
EXAMPLES
- 01
Hangover ranking by congeners
From least to most hangover-inducing in comfortable amounts: ethanol in orange juice, beer, vodka, gin, white wine, whiskey, rum, red wine, and brandy at the top. Because ethanol in orange juice ranks lowest, sugar is not the culprit. Congeners such as nitrites, which add flavor, track with severity.
- 02
Alcohol gives you pseudo-sleep, not real sleep
Citing Matt Walker, Huberman says even one glass of wine or one beer disrupts slow-wave and REM sleep. Drinking to fall asleep produces low-quality rest, which is part of why hangovers feel so bad.
- 03
Resveratrol doesn't rescue red wine
Even if resveratrol is beneficial, which is debated, you would need so much red wine to get a useful dose that the harms would outweigh any benefit. He notes David Sinclair confirmed this on an earlier episode.
- 04
Cold for clearance, but not while drunk
A small literature suggests raising epinephrine may speed parts of alcohol metabolism, lending some support to the old cold-shower lore. Because alcohol lowers core body temperature, getting into a pool or lake while inebriated is dangerous; only use cold exposure once sober.
OTHER RELEVANT
- 01
Rebuild your gut with low-sugar fermented foods
Justin Sonnenburg and Christopher Gardner's Stanford work found that 2–4 servings a day of kimchi, sauerkraut, natto, kefir or live-culture yogurt lowered inflammatory markers. This hasn't been tested specifically in alcohol use disorder, but Huberman considers it a logical repair step. Probiotics and prebiotics are an alternative with less human data.
- 02
Partially offset cancer risk with folate and B12, without relying on them
Folate and B vitamins, especially B12, have been shown to reduce, but not eliminate, alcohol-related cancer risk, probably because alcohol disrupts B-vitamin pathways. They are not a license to drink.
- 03
Manage a hangover with a few things that work
No single remedy works; Examine.com's review of purported cures, from Japanese pear juice to yohimbine, finds weak evidence. Electrolytes before bed and on waking, fermented foods and safe cold exposure address dehydration, gut disruption and depleted epinephrine and dopamine.
- 04
Quitting heavy use needs medical guidance
For people with serious alcohol use disorder, stopping cold turkey can be medically dangerous. The path to sobriety differs between people, so work with clinicians. Reward and pain systems reset after abstinence, with timing that depends on how much and how long you drank.