Limited alcohol intake may still have negative consequences for brain health

A new study conducted by the University of Pennsylvania found an association between an alcohol intake of one to two drinks per day and structural changes to the brain linked to cognitive impairment. In addition, researchers found that the brain’s structure changed more as alcohol consumption increased.

The study, published in Nature Communications set out to discover whether alcohol consumption impacted the white and gray matter volumes of the brain. To do so, researchers analyzed biomedical data from 36,678 healthy middle-aged and older adults using the UK Biobank. Researchers paid special attention to the brain MRIs of subjects to calculate the brain’s different white and gray matter volumes. The study controlled for brain volume, height, weight, handedness, sex, socioeconomic status, genetic ancestry, smoking status, and county of residence. Alcohol intake was determined through a survey given to UK Biobank participants that was scaled from zero alcohol consumption to four or more drinks per day. Participants were grouped by average consumption levels.

Results showed a correlation between average alcohol consumption levels and reductions in white and gray matter volumes. Researchers found that brain volumes did not significantly differ between those who had zero alcohol intake and those who had one drink per day. However, they saw a notable reduction in brain volume from those who drank one drink a day to those who drank two drinks per day. Reduction levels seemed to continue as alcohol consumption increased.

“It’s not linear,” said lead researcher, Remi Daviet, PhD, in a statement. “It gets worse the more you drink.”

Researchers then compared the reductions in brain volume to brain volume reductions involved in aging. They found that with each additional alcoholic drink consumed per day, effects of aging increased. Researchers suggested that going from zero to one drink per day was equivalent to half a year of aging, while going from zero to four drinks a day was equal to 10 years of aging. 

“There is some evidence that the effect of drinking on the brain is exponential,” said Daviet. “So, one additional drink in a day could have more of an impact than any of the previous drinks that day. That means that cutting back on that final drink of the night might have a big effect in terms of brain aging.”

Researchers said brain reductions were not localized. Future studies should look at effects of sporadic binge drinking compared to daily drinking, and determine causation, according to the study’s researchers.