Moderate drinking can reduce risks of Alzheimer's dementia and cognitive decline
The study stresses that it's the moderate drinking that can reduce the risks of Alzheimer's dementia and cognitive decline, but alcohol abuse can damage the brain.
Moderate drinkers often have lower risks of Alzheimer's disease and other cognitive loss, according to researchers who reviewed 44 studies.
In more than half of the studies, published since the 1990s, moderate drinkers of wine, beer and liquor had lower dementia risks than nondrinkers. In only a few studies were there increased risks.
"Alcohol is a two-edged sword," said Michael Collins, Ph.D., a professor and neuroscientist at Loyola University Chicago Stritch School of Medicine and lead author of the refereed report in the journal Alcoholism: Clinical and Experimental Research. "Too much is bad. But a little might actually be helpful."
Moderate alcohol consumption generally is defined as 1 drink or less per day for women and 1-2 drinks or less per day for men.
The article will be published in the February 2009 issue of the journal, and is available on line now. The article summarizes a roundtable, organized by Collins, held at the Research Society on Alcoholism meetings in Chicago in 2007.
"The pathological damage and vast social havoc from addiction to and abuse of alcohol are well known, and of necessity should continue to receive primary attention by doctors, scientific researchers and health professionals," Collins and colleagues write. "However, light-to-moderate responsible alcohol consumption "appears to carry certain health benefits."
Long-term alcohol abuse can cause memory loss and impair cognitive function. It's unknown why moderate alcohol use appears to have the opposite effect. One theory is that the well-known cardiovascular benefits of moderate alcohol consumption also can reduce the risk of mini strokes that cause dementia.
Collins and another Loyola professor, neuroscientist Edward Neafsey, Ph.D., suggest a second possible explanation. Small amounts of alcohol might, in effect, make brain cells more fit. Alcohol in moderate levels stresses cells and thus toughens them up to cope with major stresses down the road that could cause dementia.
For most people who drink responsibly and in moderation, there's probably no reason to quit. But because of the potential for alcohol to be abused, Collins and Neafsey do not recommend that abstainers begin drinking. The researchers note there are other things besides moderate drinking that can reduce the risk of dementia, including exercise, green tea, education and a Mediterranean diet high in fruits, vegetables, cereals, beans, nuts and seeds.
Moreover, there are times when people should never drink, including adolescence, pregnancy and before driving, Collins said.