Saturday, May 5, 2007

Honey, I shrunk my brain...

Would that crisp Chardonnay or cool refreshing lager go down as guiltlessly if you knew that every sip contributed, imperceptibly, to the shrinkage of your brain?

A new study has found that over time, drinking alcohol, whether moderately or heavily, was associated with decreased brain volume.

And while heavy drinkers had significantly less brain volume than light or moderate drinkers, only abstainers were found to have no alcohol-related brain atrophy. The effect was the greatest in women.

Whether the loss of brain volume actually was caused by alcohol, and whether it contributed to any decreased cognitive function, remains to be seen.

But the study is the latest cautionary note in the perplexing issue of whether moderate alcohol consumption is good for one's health. It raises the question of whether drinking may be good for the heart but not so good for the brain.

"That's the big question," said lead author Carol Ann Paul, a researcher with Wellesley College. "I would be reluctant to tell people not to enjoy their drink a day. But that is something to think about."

The research, which included MRI brain scans of 1,839 people who are part of a Framingham study, was presented Wednesday at the American Academy of Neurology annual meeting.

Based on their drinking habits, the people, who ranged in age from 34 to 88, were divided into five groups: non-drinkers; former drinkers; low drinkers (one to seven drinks a week); moderate drinkers (eight to 14 drinks a week); and heavy drinkers (more than 14 drinks). Their average age was 61.
More drink, more shrink

Compared with the non-drinkers, all of the groups had progressively greater amounts of decreased brain volume, with the biggest decrease in the heavy drinkers. The heavy drinking group had a 1.25% decrease in brain volume.

Brain volume decreases somewhat as people age. A loss of 1.25% is approximately equivalent to one to two years of normal aging, Paul said.

A subgroup of people in the study who had a 12-year history of heavy drinking had an average 1.6% reduction in brain volume.

While, in general, decreased brain volume is associated with decreased cognitive function, the study did not measure that, said Ann Helms, an assistant professor of neurology at the Medical College of Wisconsin.

"It (the study) is a valuable observation," said Helms, who was not a part of the study. "But we need to say, 'what is the cognitive effect of this?' "

Helms said the study raises an interesting question about the role of alcohol in health.

One the one hand, a great deal of research suggests that moderate alcohol consumption may be good for the heart and may also help prevent strokes. But alcohol also may be toxic to brain cells, Helms said.

"There is no safe level of alcohol when it comes to loss of brain volume," she said. "If you are worried about cognitive function, you shouldn't drink anything."
How much is too much?

Helms said she would not recommend that anyone start or stop drinking moderately for health reasons.

However, she said it is reasonable for people to base their drinking habits on individual risk.

For instance, a person with a family history of heart disease or stroke might want to drink moderately. But a person with a family history of dementia or Alzheimer's disease might want to avoid alcohol, she said.

"Too much is not good," Helms said. "Unfortunately, it's not clear what that point is for any person."

The effect can be especially pronounced for women. Their rate of brain volume decline was roughly 50% more than men across the various drinking categories.

Women tend to be affected by alcohol more than men, because they metabolize and absorb it differently. As a result, they achieve higher levels of alcohol in their blood and become more impaired from the same amount consumed by men of the same body weight.

Heavy drinking among men and women is known to be bad for both the heart and the brain, said Bhupendra Khatri, director of the Center for Neurological Disorders at Aurora St. Luke's Medical Center in Milwaukee. Some of that likely is due directly to the alcohol and some of it probably is caused by the poor nutrition often found in heavy drinkers, he said.

What is interesting about the study is that it showed for both women and men that alcohol consumption was associated with a linear decline in brain volume from light drinking to heavy drinking, he said.

"The more you drink, the more it (the brain) atrophies," said Khatri, who was not part of the study. "There is a fine balance in life. You need to look at your own risk factors."

source: Milwaukee Journal Sentinel

1 comment:

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