- Researchers found a correlation between drinking alcohol and loss of brain tissue.
- Parts of the brain naturally die off with age, but a drink or more a day could add to that effect.
- The more individuals drank, the greater the loss of brain volume observed in the study.
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A new analysis of alcohol consumption and brain volume found that drinking even a glass of wine or one beer a day was linked to a brain-ageing effect.
Contrary to past research suggesting that a few drinks a week could boost word recall, the latest study of booze and the brain concluded that even light-to-moderate drinking could be connected to later cognitive decline.
Researchers from the University of Pennsylvania considered data from more than 36,000 middle-aged and older adults — about double the size of similar studies — who shared health information with the UK Biobank, including lifestyle surveys and brain scans.
They found that the more individuals reported drinking, the stronger the association with loss of brain matter, according to the paper published in Nature Communications. Each unit of alcohol, or every half a drink, added to a person's daily average was linked to a greater loss of tissue.
While the study did not look to prove a cause-effect relationship, the authors said heavy drinkers could benefit most from taking note of this concerning trend.
"One additional drink in a day could have more of an impact than any of the previous drinks that day," Remi Daviet, co-author of the study, said in a press release. "That means that cutting back on that final drink of the night might have a big effect in terms of brain ageing."
Parts of the brain die as you age
It's normal to lose your marbles a bit as you age, and that's reflected in the brain's physiology.
Studies have shown how normal cognitive decline is accompanied by a loss of gray matter, the parts of the brain that do the bulk of information processing. The rest of the brain is referred to as white matter, as the connections between parts of the brain show up as white branches on a brain scan.
The team at Penn found reductions in overall brain volume — including gray and white matter — associated with various levels of drinking. To put that loss in context, they compared it to the changes that typically occur with ageing.
Going from an average of zero drinks per day to one a day was associated with the equivalent of two years of ageing in a a sample of 50-year-olds. The relationship appears to be roughly exponential, authors noted, as going from zero drinks to four was linked to more than 10 years of brain ageing.
'Safe' alcohol limits may come with some risk
The levels of alcohol consumption linked to brain changes were within national guidelines for drinking safely, and some of the study authors are prompting a second look at the standards.
For instance, the National Institute on Alcohol Abuse and Alcoholism recommends that women consume an average of no more than one drink per day and says that men can have two drinks a day. If kept up daily, that much drinking could indicate potential harm to the brain.
As for the few drinks a week crowd, having less than a drink a day on average was linked to minimal brain tissue loss, or about half a year of ageing.
"The fact that we have such a large sample size allows us to find subtle patterns, even between drinking the equivalent of half a beer and one beer a day," Gideon Nave, a corresponding author on the study and faculty member at Penn's Wharton School, said in a press release.