Cutting down on alcohol

What it is about

Cutting down on alcohol is not an active substance but a lever of leaving something out. The topic is often sidestepped in biohacking, because alcohol is a cultural asset that has brought people together for thousands of years. This is not about morality, but about what can be measured in the body, and about conscious use instead of autopilot. The term mindful drinking has become established for this.

In the body, alcohol is first broken down into acetaldehyde, a cell toxin. The International Agency for Research on Cancer classifies alcohol as a Group 1 carcinogen, in the same category as tobacco, asbestos and radiation. The WHO names at least 7 types of cancer linked to alcohol, including colorectal cancer and breast cancer in women. About half of all alcohol-related cancer cases in the WHO European Region arise from light to moderate drinking, not from heavy drinking. Then there is the energy: 7 kcal per gram, almost as much as fat at 9 kcal, but without satiety.

The end of the red wine myth

For decades, observational studies showed a J-curve: moderate drinkers seemed to live longer than abstainers. The catch lay in the comparison group. Among non-drinkers there are many former drinkers who stopped for health reasons, and people who abstain because of illness or medication. Next to this already burdened group, moderate drinkers automatically look healthy.

A meta-analysis of 107 cohort studies with 4,838,825 participants corrected for this bias and compared only with lifelong non-drinkers. The result: occasional or low drinking did not significantly reduce the risk of death. Even sharper is Mendelian randomization, in which gene variants that influence drinking behavior serve as a natural random experiment. In the China Kadoorie Biobank with 512,715 adults, the U-curve disappeared with this approach: the risk of stroke rose continuously with the genetically predicted amount of drinking.

What happens during sleep

Here you can measure the effect yourself. In a Finnish study, 4,098 employees wore heart rate sensors, and each person was compared with themselves on nights with and without alcohol. Even with a small amount, the recovery state calculated from HRV fell by 9.3 percentage points in the first hours of sleep, by 24.0 with a moderate amount and by 39.2 with a high amount. Heart rate during sleep rose on average by 1.4, 4.0 and 8.7 beats per minute. Exercise and young age did not protect against this.

Alcohol initially makes you drowsy, but it is a sedative, not a sleeping aid. An overview of all studies in healthy people shows: the first half of the night becomes calmer, the second more restless, and the first dream sleep phase starts later at any amount. The total REM share falls with moderate and high amounts. Many know the picture from their own dashboard: the evening with alcohol is the worst metric the next morning.

Training, brain and hangover

After intense training, alcohol reduced muscle protein synthesis by 24 percent in an Australian study, even though protein was consumed at the same time, and by 37 percent when it was combined only with carbohydrates. The amount, however, was high, on average 12 standard drinks. For the brain, the UK Biobank provides imaging data from 36,678 adults: more alcohol was associated with smaller brain volume and poorer white matter structure, visible from an average of 1 to 2 units a day.

And a hangover is more than dehydration; it is a mix of acetaldehyde, inflammatory response and disturbed sleep. Dark drinks with many fermentation congeners cause worse hangovers: in a randomized study, young adults felt worse after bourbon than after vodka, but next-day performance suffered equally with both.

Drinking less in practice

Measure instead of guessing: two weeks completely without, while watching HRV, resting heart rate and sleep, is often more convincing than any study. Decouple occasions, because you drink many glasses out of habit, not for enjoyment. Take alcohol-free alternatives seriously, which have matured in the meantime. If you do drink, then early in the evening with some distance from bedtime. And shape your environment: what is not in the house does not get drunk.

What the studies show

Zhao et al., JAMA Network Open 2023 — 107 cohorts

Systematic review and meta-analysis with 4,838,825 participants and 425,564 deaths. After correcting for former drinkers and other biases, occasional drinkers and low-volume drinkers had no significantly lower risk of death than lifelong non-drinkers. From 45 grams of alcohol a day the risk rose markedly, and earlier in women.

Voskoboinik et al., New England Journal of Medicine 2020 — atrial fibrillation

Randomized, open-label, 6 hospitals, 140 patients with at least 10 standard drinks per week. The abstinence group reduced its consumption from 16.8 to 2.1 drinks per week. Recurrences after 6 months: 53 versus 73 percent; the proportion of time in atrial fibrillation fell from a median of 1.2 to 0.5 percent. Both primary endpoints were met.

Pietilä et al., JMIR Mental Health 2018 — HRV in real life

4,098 Finnish employees, each person compared with themselves on nights with and without alcohol. Dose-dependently more stress activation and less recovery during sleep, measurable even with a small amount. The recovery state fell by 9.3, 24.0 and 39.2 percentage points, and heart rate rose by 1.4, 4.0 and 8.7 beats per minute.

Where the data stop

Much of the data is observational. The genetic study from China supports causation for blood pressure and stroke; for heart attack it found no significant association. The inhibition of muscle protein synthesis was shown in 8 men after about 12 standard drinks; this study allows no conclusion for one or two glasses. For REM sleep, the effect of small amounts is inconsistent, even though HRV already responds; a pulse increase of five to ten beats corresponds more to moderate to high amounts.

The one-month abstinence study is an observation with self-selected groups and measured neither HRV nor sleep architecture. That early fatty liver can regress within a few weeks is often said, but it is not supported by the studies analyzed here. And the risk curve at very low amounts is flat: the Canadian guidelines classify up to 2 standard drinks per week as low risk.

Status, approval and legal

Cutting down on alcohol requires no approval and no dose. The official assessment has shifted considerably within a few years. In 2023, WHO Europe declared that there is no amount that can be considered safe. In the same year, Canada switched its guidelines to a risk continuum: 2 standard drinks per week or fewer are considered low risk, and from 3 to 6 the risk of several types of cancer rises. In 2024 the German Nutrition Society replaced its old reference value and recommends abstaining from alcoholic drinks; children, adolescents, pregnant and breastfeeding women should generally not drink alcohol.

Safety

Drinking less is risk-free for almost everyone. It is different when someone drinks dependently: anyone who notices that stopping is difficult, drinks secretly or already thinks about drinking in the morning needs medical support or addiction counseling rather than self-optimization. General practitioners, addiction counseling services and self-help groups help confidentially. Alcohol enhances the effect of sedating substances, competes in the liver with many medications for the same breakdown pathways and can undermine appetite control with GLP-1 medications. Anyone taking medications or supplements should clarify interactions with a physician or pharmacy.

Sources

• WHO Europe: No level of alcohol consumption is safe for our health, 2023
• DGE (German Nutrition Society): Ideally zero alcohol, position paper 2024
• Zhao et al., JAMA Network Open 2023
• Millwood et al., Lancet 2019
• Voskoboinik et al., New England Journal of Medicine 2020
• Pietilä et al., JMIR Mental Health 2018
• Ebrahim et al., Alcoholism: Clinical and Experimental Research 2013
• Parr et al., PLoS One 2014
• Mehta et al., BMJ Open 2018
• Daviet et al., Nature Communications 2022