Just 5 Drinks A Week Can Damage Your Brain

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Before you pour that nightly glass of beer or wine, consider this: You could be doing lasting damage to cognition and memory. So suggests new research published in The BMJ this month, which found having just four strong beers or five glasses of wine a week is linked to increased risk of mental decline. 

While these findings run in direct opposition to other studies that have shown moderate drinking can be good for your health, the size and depth of this research can’t be ignored: The authors looked at data from 550 healthy middle-aged Brits, and analyzed changes in their brain structure and cognitive abilities during a 30-year period. The people evaluated in this study were mostly well-educated, middle-class government workers, none of whom were addicted to alcohol. Still, the researchers accounted for factors that could influence brain health, such as age, physical activity, smoking, and stroke risk. Despite these factors, the more alcohol these folks drank, the worse shape their brains were in.

Looking at the hippocampus, a brain region important for memory and one that atrophies in the early stages of Alzheimer’s disease, the heaviest drinkers had the most shrinkage. But even those who consumed a weekly four to six beers, or five to seven glasses of wine, were a staggering three times more likely to have hippocampal atrophy than nondrinkers. “Since hippocampal size is associated with memory, you would expect people with smaller hippocampi to have poorer memory either now or in the future,” says lead author Anya Topiwala, a psychiatry researcher at the University of Oxford. There was no protective effect from imbibing one to four beverages a week.

As for other areas of the brain, “we found the higher alcohol consumption, the lower the grey matter density in the hippocampi and amygdalae and the poorer the quality of the white matter tracts — the ‘cabled wires’ — in the brain,” Topiwala says. “Both effects were significant. Reduced grey matter and white matter microstructure are each associated with poorer cognitive function.”

The study also found that moderate drinkers declined more quickly on a lexical fluency test, which asks people to come up with as many words beginning with a certain letter as they can within one minute. Topiwala says this task reflects complex cognitive processes.

The fact that moderate drinking had such a profound impact on brain structure surprised the researchers, mainly because past studies have suggested it may protect against memory loss and dementia. “I suspect the discrepancy is because previous studies did not fully account other characteristics of moderate drinkers,” Topiwala says. “For instance, we know that people with higher IQs and education, those who would do better at memory tests, drink more. These characteristics may have masked the true effects of moderate drinking.”

Because this was an observational study, it can’t tell us exactly how a handful of drinks a week impacts the brain. But according to Topiwala, it’s very difficult to investigate this question any other way. She says that with heavy use, alcohol acts as a toxin to brain cells and also leads to vitamin deficiency, so it’s possible that moderate drinking may yield these same effects, albeit to a milder degree.

Reason enough to ask yourself if you really need tonight’s “just because” beer.