Alcohol and Brain Size
By Rose Hoban
Chapel Hill, NC
04 May 2007
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.