Moderate Drinking May Shrink Your Brain by 1 Percent. Is It Worth It?
Scientists have long known that heavy alcohol use shrinks the brain, but it's not clear whether or not moderate drinking has a similar effect.
Researchers from the University of Helsinki in Finland explored the possible link within a sample of 353 Finnish men and women aged 39 to 45. On average, the subject group reported moderate alcohol consumption, indicated by an AUDIT-C score of 3.92. Such a score is roughly equivalent to drinking two to four times a month, having between three and four drinks a session, and occasionally imbibing more than six drinks in a day every couple months or so. Subjects' brain volumes were measured using magnetic resonance imaging (MRI).
The researchers uncovered a dose-dependent link within the study group. For every one point increase in the AUDIT-C score (indicating heavier drinking), brain volume decreased by roughly 0.2%. This link held in men even when controlling for smoking, but it did not hold for women, barely missing statistical significance.
Prior studies have also explored whether or not moderate alcohol consumption shrinks the brain. A slim majority say "yes" while the rest say "no". The landscape of research suggests there may be a tenuous link, but it may not be clinically meaningful. Translation: Moderate drinking, in the range of 7 - 14 drinks a week, may shrink your brain volume a little bit, perhaps by 1%, but you likely won't experience any deleterious effects on cognitive function.
"There’s a great deal of doubt about whether the atrophy seen on MRI is due to loss of brain cells or to fluid shifts within the brain," Harvard epidemiologist Dr. Kenneth J. Mukamal told the Harvard Health Blog, adding that the reduction in brain size could actually be reversed within weeks of abstaining from alcohol.
Given what we know, is moderate alcohol consumption worth 1% of your brain volume? For many, the answer is a resounding "I'll have another!"
Source: Immonen, S., Launes, J., Järvinen, I. et al. Moderate alcohol use is associated with decreased brain volume in early middle age in both sexes. Sci Rep 10, 13998 (2020). https://doi.org/10.1038/s41598-020-70910-5