Wednesday, August 19, 2009

Does one drink a day help keep dementia away?

Although it’s clear that heavy drinking is bad for your health, some studies have suggested that drinking “moderately,” defined as up to two alcoholic beverages per day, may actually improve cognition (thought processing in the brain). In a 2005 study in the New England Journal of Medicine, Dr. Meir Stampfer and colleagues from Harvard Medical School examined the relationship between moderate drinking and measures of brain function in women age 70 years and older.

Women in the study completed six dietary questionnaires between 1980 and 1998, including questions about frequency and type of alcohol use. They were classified into three groups based on average daily alcohol consumption: non-drinkers (55 percent of participants), those who drank up to one drink daily (44 percent), and those who drank one to two drinks per day (5 percent).

Specially trained nurses, who were not given information about the womens’ drinking habits, tested their memory and cognition in telephone interviews between 1995 and 1997. While nondrinkers and women who consumed one to two drinks daily had similar cognitive scores, women who consumed less than one drink daily had higher average scores, and their risk of being classified as cognitively “impaired” was 20 percent less than that of nondrinkers. The type of alcoholic beverage consumed did not affect the results.

Given the impracticality of using alcoholic beverages in a randomized clinical trial, it is unlikely that we will ever know conclusively if any amount of alcohol is good for the mind, and if so, how much. The observational design of this study leaves open the possibility that women with better cognitive scores were more likely to consume moderate amounts of alcohol, rather than the other way around. It would be premature to recommend that women who are nondrinkers start consuming alcohol to prevent dementia. On the other hand, this study suggests that women who drink up to two alcoholic beverages per day will be no worse off, and may possibly fare better, than their nondrinking peers.

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Note: the above posting is adapted from an article I wrote in the November 1, 2005 issue of American Family Physician.