It appears that heavy drinkers have smaller brains than non-drinkers, a new study published in the Archives of Neurology suggests. Drinking more than 14 alcoholic drinks a week was associated with a gradually decrease in brain size. Actually, such drinking might speed up the shrinking of the brain, a process that naturally comes with age.

The study suggests that the more people drink, the more their brain volume decreases. This association was more pronounced in women because women’s typically smaller body size makes them more vulnerable to alcohol. They absorb alcohol more rapidly and have less blood to dilute alcohol on average.

Researchers from Wellesley College, Mass., Boston University, the Framingham Heart Study and the University of California, Davis, studied 1,839 adults, who were part of the Framingham Offspring Study, which began in 1971. The participants were asked how much alcohol they drank each week, then were divided into four groups: abstainers, former drinkers, or low drinkers (they drank one to seven drinks per week), moderate consumers (eight to 14 drinks per week) or high consumers of alcohol (more than 14 drinks w week). Between 1999 and 2001, participants underwent magnetic resonance imaging (MRI) and a health examination.

Men were more likely than women to be moderate or heavy drinkers. However, most participants fell into the “low-consumption” category.

Participants in the lowest drinking group had brain volumes of 78 percent of their total cranial volume, compared with 78,6 percent in the group of abstainers. Heavy drinkers had brain volumes of 77.3 percent. Researchers noted that increasing alcohol consumption was associated with decreasing total cerebral brain volume, which remained significant after adjustment for head circumference, age, sex, education, body mass index, and Framingham Stroke Risk Profile score.

Brain volume decreases with age at an estimated rate of 1.9 percent per decade. At the same time, the brain acquires white matter lesions as it gets older. Lower brain volumes and larger white matter lesions also occur with the progression of dementia and problems with thinking, learning and memory.

Previous studies have found that drinking and smoking are two of the most important risk factors for Alzheimer’s disease. Both drinking and smoking affect the brain, damaging cells and synapses.

On the other hand, several studies have shown that moderate drinking can have a beneficial health effect, but researchers consider more than two drinks a day to be severe. If we can reduce or eliminate excessive consumption of alcohol, we could substantially delay the onset of Alzheimer’s and other degenerative diseases, reducing the number of people affected by these diseases at any point in time.

Contrary to other studies, the researchers showed that even low levels of drinking are not protective. The study-authors noted that moderate drinking, unlike the previous associations with cardiovascular diseases, had no protective effect on the age-related brain shrinkage. “The public health effect of this study gives a clear message about the possible dangers of drinking alcohol,” the researchers concluded.