Medical science says our brains shrink just less than 2% per decade as we age but a team of Wellesley College researchers say heavy drinking can speed that rate of shrinkage while increasing the risk of dementia and otherwise impaired cognitive function.

The Wellesley study, led by Carol Ann Paul, MS, is particularly intriguing in light of recent studies which suggest moderate drinking of alcoholic beverages lowers one’s risk of developing cardiovascular disease.  Paul’s team wanted to know if the alcohol had the same effect on the natural decline in brain volume associated with the aging process.

Smaller brain volume is associated with dementia and cognitive impairments that include diminished ability to think, learn, and remember.  As brain volume decreases and mental health declines, lesions of the brain’s white matter grow, further affecting mental capacity.

The Wellesley study shows that brain volume shrinkage is greatest where the most alcohol is consumed.  The research team turned to 1,839 adults, the average age of whom was 60, who underwent magnetic resonance imaging (MRI) of their brains and a health exam between 1999 and 2001.  Part of the health exam included self-reporting of the weekly number of alcoholic beverages consumed plus the individual’s age, gender, education level, body mass index (BMI), height, and Framingham Stroke Risk Profile.

All study participants are enrolled in the Framingham Offspring Study, begun in 1971 as a continuation of the Framingham Heart Study.  The offspring study is a lifelong monitoring of the health and lifestyles of the children born to the original study’s participants and spouses.  The Framingham Stroke Risk Profile assesses a person’s risk of stroke according to his or her gender, age, blood pressure, and related factors.

Study participants reported low levels of alcohol consumption in general and the men were more likely to identify themselves as moderate or heavy drinkers than the women were.  The MRI scans for brain volume indicated a direct link between brain volume and alcoholic intake, with the brains of the heaviest drinkers shrinking the fastest.

The study revealed gender differences as well, with women’s brains showing more effect of alcohol consumption than the brains of the men.  The research team suggests the difference may be biological since women are generally more susceptible to the effects of alcohol and are usually smaller in overall size than men.

The research team would like to see additional studies to confirm their findings but suggest in the meantime that people remain cautious about alcoholic beverages.  Even though alcohol has been shown to be somewhat beneficial to cardiovascular health, it is not beneficial to brain volume and function.

The October issue of Archives of Neurology carries the full report.  The National Heart, Lung, and Blood Institute, which conducted the Framingham Heart Study as a part of the National Institutes of Health, provided support for this study as did the National Institute of Neurological Disorders and Stroke.

Source: JAMA