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Dec. 5--Moderate alcohol consumption, which appears to be beneficial to the heart, may not be so good for the brain, according to a new study showing that middle-aged drinkers had smaller brains than non-drinkers. Quotable
The study found that moderate drinking not only did not protect against stroke, but it also was associated with brain atrophy, presumably the result of brain cell death.
The study, by researchers at Johns Hopkins University, used magnetic resonance imaging to look at the brains of 1,909 people in their mid-50s who were categorized by their drinking habits, which ranged from those who never drank to moderate drinkers (more than seven drinks a week).
The researchers found that as drinking increased, brain atrophy was more common, although the amount of reduced brain size was very small.
The study supports the possibility that alcohol may have both good and bad effects on the brain, according to its senior author, F. Javier Nieto, a former Johns Hopkins researcher who now is a professor of family medicine and chairman of the Department of Population Health Sciences at the University of Wisconsin-Madison.
Weighing those effects and also factoring in the impact of alcohol on heart health will be difficult until more research is done, Nieto said. He cautioned people about changing their habits because of the study.
"I'm a moderate drinker," Nieto said. "I'm going to continue drinking my glass of wine every night with dinner."
Both Nieto and the study's lead author, Jingzhong Ding, a research associate at Johns Hopkins, said it is possible that moderate alcohol use may be beneficial for the blood vessels of the brain, much as it appears to be for coronary arteries. Although the study did not find a lower risk of stroke from moderate drinking, other studies have.
At the same time, moderate drinking may have a separate toxic effect on brain cells, which would explain the brain atrophy.
Other research using MRI has shown an association between brain atrophy and poor cognitive functioning as well as reduced motor skills.
"There can be two different things going on," Ding said. "For people who are drinking (moderately), I don't think they should worry too much."
The study also suggests that people need to consider their individual risk factors and keep abreast of additional research about alcohol and the brain, said Edgar Kenton III, a professor of clinical neurology at Thomas Jefferson University in Philadelphia and a spokesman for the American Heart Association.
For instance, drinkers with other risk factors, such as high blood pressure or being overweight, may want to cut back on their drinking, he said.
"There's been controversy about alcohol and stroke for some time," Kenton said. "It's been felt that two drinks a day may keep the neurologist away."
However, it is possible that, for some drinkers, alcohol's overall effect is much like penicillin is to people who have an allergy to the drug, he said.
The study "is one more piece of evidence that alcohol may a risk factor (for stroke) or may not be," Kenton added. "It's clearly a risk factor for (brain) atrophy.
"This study shouldn't change anyone's drinking habits, except to make them aware that alcohol causes brain atrophy."
While some studies have shown that moderate alcohol consumption of up to two drinks a day appears to reduce the risk of stroke, one study found no protection.
Research involving heavy drinkers, however, has shown that alcohol increases the risk of stroke as well as decreases brain size.
Still another factor to consider is that, in a study earlier this year, moderate drinking, defined as one to six drinks a week, was shown to lower the risk of developing dementia by about 35 percent, compared with no drinking at all.
Several studies also have shown that moderate drinking can reduce the risk of developing heart disease.
Shi-Jiang Li, a professor of biophysics and a brain imaging expert at the Medical College of Wisconsin, said he agreed with the Johns Hopkins researchers' conclusion that moderate alcohol use is not protective against stroke.
However, he questioned the conclusion that alcohol was associated with brain atrophy. He said the small amount of brain atrophy that was found could be explained by the margin of error in the study.
For their study, the Johns Hopkins researchers used MRI to look at the ventricular and sulcal areas, which are fluid-filled spaces that are devoid of brain tissue. An increase in the size of those areas indicates a decrease in nearby brain tissue.
The researchers found that the more the subjects in the study drank, the greater the size of the ventricular and sulcal areas.
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