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Alcohol and Brain Size

Medical researchers have found that drinking small amounts of alcohol has benefits for the cardiovascular system. Neurologist Carol Ann Paul began to wonder if it could have similar positive effects on the brain.

Paul, an instructor at Wellesley College in Massachusetts, took data from the Framingham Study. That long-term medical research project has followed residents of the town of Framingham, Massachusetts since 1948. Several years ago, the Framingham researchers took brain scans of people in the community who ranged in age from 34 to 88 years.

Paul says she looked at records from more than 18-hundred of these people and divided them into five groups. "And these groups were abstainers who didn't drink and former drinkers. And then I had three (more) groups: low, moderate and high drinkers. Low drinkers had 1 to 7 drinks a week, moderate drinkers consumed 8 to 14 drinks per week while high drinkers had greater or equal to 15 drinks a week."

Paul measured total cranial volumes and the amount of space the subjects' brains occupied inside their skulls. Brains normally get slightly smaller as people age, but Paul found the consumption of alcohol accelerated this process, even when she took other factors into account. And she says the more alcohol subjects drank, the more brain volume they lost.

"Alcohol decreased brain volume by minus 2 point 5 percent per drink category," she explains. "Normal people lose about point-19 percent of their brain per year, so this reduction is equal to one or two years of normal brain aging."

Paul says she doesn't know whether or how this decrease translates into decreased brain function. But she says she was surprised that alcohol had such a deleterious effect on brain structure. "What this suggests," Paul adds, "is that while alcohol is beneficial to the cardiovascular system, to the heart and the blood vessels -- and it probably has the same benefit to the blood vessels in the brain -- I think alcohol is doing something else to the neurons of the brain -- the cells that make up the brain."

Paul spoke to us from the annual meeting of the American Academy of Neurology in Boston, where she presented her research.