Alcohol’s effects on memory depend on the amount consumed. Heavy alcohol consumption, especially binge drinking, takes a toll on memory function. In a study published in Epidemiology, midlife binge drinking more than tripled the risk of developing dementia in later life. (Binge drinking was defined as consuming more than five bottles of beer or one bottle of wine on one occasion at least monthly.) The risk of dementia was more than 10 times higher among drinkers who had passed out at least twice during a 12-month period.
Mild to moderate drinking, in contrast, may have a protective effect. If there is protection, the mechanisms by which it could help are not understood. Some research suggests that being a nonsmoker factors into the protective effect of alcohol.
Although no optimal level of alcohol consumption has been established, experts recommend that men consume no more than two drinks per day and women, no more than one drink per day. (One drink equals 12 oz. of regular beer, about 5 oz. of wine, or 1.5 oz. of 80-proof distilled liquor.) People age 65 and over should drink less than these amounts.
Women who have an elevated risk of breast cancer should speak with their doctors about drinking alcohol, because evidence suggests that as little as one drink a day can boost breast cancer risk. Research is still emerging on how the type of alcohol—beer, wine, or liquor—affects dementia risk.
Despite the possible cognitive benefits of moderate alcohol consumption, nondrinkers should not start drinking to prevent dementia. The risks of excessive alcohol consumption are many, including alcoholism and automobile accidents.