Booze boosts brainpower
Moderate alcohol consumption protects women from cognitive decline.
Can a drink a day prevent mental decline? The finding that older women who consume moderate amounts of alcohol score better on cognitive tests suggests that it can.
An investigation has revealed for the first time that the brain can benefit from consumption of both beer and wine. In the early 1990s, researchers often referred to the 'French paradox' to support the idea that wine promotes good health1.
The phrase refers to the fact that French people have a lower risk of heart attack than Americans do, even though their diets contain similar levels of fat.
More recent studies have also linked modest beer consumption with a decreased risk in heart disease2.
But although researchers know that moderate drinking benefits the heart, there haven't been any significant studies of whether moderate alcohol intake has any effect on the brain.
Drinking for thinking?
Now, epidemiologist Francine Grodstein of the Harvard School of Public Health in Boston, Massachusetts, and her colleagues have carried out a study involving more than 12,000 women, aged between 70 and 81 years old.
The group used data from the Nurses' Health Study, which was started by researchers at Harvard Medical School in 1976 and is still ongoing. They used data in which the 12,000 women were asked to undergo a series of cognitive tests over the telephone.
One of the assessments asked the women to name as many animals as they could in one minute. Others measured their ability to remember information and recite long series of numbers backwards.
Rush University Medical Center, Chicago, Illinois
They found that the women who had the equivalent of one drink a day had a 23% lower risk of becoming mentally impaired during the two-year period, compared with non-drinkers.
It made no significant difference whether they drank beer or wine, the researchers report this week in the New England Journal of Medicine3.
Proceed with caution
How might alcohol be boosting brainpower? The epidemiologists say that previous findings about the cardiovascular benefits of drinking might extend to the brain. They speculate that better blood flow could help to preserve cognitive function, and prevent subclinical strokes.
The medical community is unlikely, however, to rush to recommend that non-drinkers change their habits to boost mental ability. "I don't think that would be an appropriate message," says Grodstein.
Although there appear to be benefits from consuming modest amounts of alcohol, "people need to be cautious about their drinking habits", she says.
"Alcohol has to be regarded as a two-edged sword. The risk of overindulgence is too well known," agrees Denis Evans, an expert on diseases affecting the elderly based at the Rush University Medical Center in Chicago, Illinois. "'Don't smoke' is a simple message, but this one is a bit more modulated."
Several studies have proposed an interaction between alcohol and a protein called apolipoprotein E, which increases one's risk of developing Alzheimer's disease. So Grodstein also looked into the idea that drinking might especially benefit people susceptible to this illness.
To do this, Grodstein and her fellow researchers looked at the test results for the subgroup of women carrying the gene that codes for apolipoprotein E. Among those with the gene, the researchers found no cognitive difference between drinkers and non-drinkers, suggesting that women susceptible to Alzheimer's disease actually get no benefit from moderate alcohol intake.
Given that studies4 have linked alcohol with benefits in Alzheimer's sufferers in the past, however, the epidemiologists remain cautious about this aspect of their study. "If there is something going on, it's very subtle," says Grodstein.
- Ferrieres, J. Heart 90, 107–111 (2004).
- Zhang, Q. et al. Alcohol. Clin. Exp. Res. 24, 52–534 (2000).
- Stampfer, M. J. et al. N. Engl. J. Med. 352, 245–253 (2005).
- Ruitenberg, A. et al. Lancet 359, 281–286 (2002).