Half a liter of beer or an average glass of wine a day can start to reduce the total volume of the brain, new research has shown, and the damage worsens as the number of daily drinks increases.
On average, 50-year-olds who drank about half a liter of beer or a glass of wine a day in the past month had a brain that looked two years older than those who drank only half the amount of beer, according to a study published this week in the journal Nature.
Another side effect of alcohol consumption
In the brains of people of that age who said that they drink three units of alcohol a day, there was a decrease in both white and gray matter, which seemed to add 3.5 years to their brain.
One alcohol unit is 10 milligrams or eight grams of pure alcohol. This means that 25 milligrams or one dose of liqueur is one unit; a can of 16-ounce beer or cider is two units; and a standard six-ounce (175 milligram) glass of wine is two units.
The brains of those who do not drink and who have started consuming an average of one unit of alcohol a day have shown aging for half a year, according to the study.
By comparison, drinking four units of alcohol a day has aged a person's brain for more than 10 years.
"It's not linear. It gets worse the more you drink," said first author Remi Daviet, assistant professor of marketing at the Wisconsin Business School at the University of Wisconsin-Madison.
"The problem with this study is that they only have information about people's habits to consume drinks during the year before the brain scan," said alcohol researcher Emmanuela Gakidou, a professor of health metric sciences at the University of Washington.
She added that she thinks that this is the main limitation of the study because "cumulative consumption of alcohol throughout life is related to the brain, and not only to the level of consumption immediately before the brain scan".
She also added that the relationship between alcohol and health is complex, and our understanding of that relationship is evolving over time.
Gakidou says that based on this study, she would not draw any definitive conclusions, but would say that the authors have identified areas for further research.
