Dec. 4, 2003
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.
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%, 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.
The study is published today in Stroke, a journal of the American Heart
Association.
Source:
Article Dec. 4, 2003 published in the
Milwaukee Journal Sentinel