Moderate Drinking Not Linked to Brain Damage, But Heavy Drinking Is, Study Finds

Over several years, having more than three drinks a day may lead to memory loss and a decline in motor functioning.

Jacob Gaffney
Posted: June 3, 2004

People who regularly have more than three drinks a day may experience a slow, almost unnoticeable decline in concentration levels, motor coordination and ability to retrieve memories, a recent study found. This slight brain damage, however, was not apparent in light to moderate drinkers.

"Our major aim was to detect early adverse effects of alcohol drinking on brain function," said lead author Dieter Meyerhoff, a radiologist at the University of California, San Francisco.

Previous studies that examined the long-term effects of alcohol consumption on the brain tended to use current or recovering alcoholics, Meyerhoff said. His team wanted to see if alcohol affects the brains of those who drink considerably less than alcoholics and function well within their families and society. The results were published in the April issue of Alcoholism: Clinical and Experimental Research.

According to prior research cited in the study, alcoholics generally consume in the ballpark of 300 drinks per month. Meyerhoff's study focused on people who consume around 100 to 200 drinks per month, a category classified as "heavy drinkers." For comparison, light to moderate drinkers -- those who consumed one to two drinks per day -- were also included. (One drink was defined as 13.6 grams of alcohol: around 2 ounces of liquor, 5 to 6 ounces of wine or 12 ounces of beer.) Nondrinkers were not studied.

Meyerhoff's team examined 46 heavy drinkers and 52 light to moderate drinkers who were recruited through ads in local newspapers and flyers. The researchers excluded people with a family or personal history of alcoholism, as well as anyone who showed signs of alcohol withdrawal or failed a breath test. Participants in both groups reported that they had followed their drinking patterns for the past three years.

All volunteers underwent a series of tests of myriad brain functions. MRIs were used to measure metabolic activity in the frontal lobes, cerebellum and thalamus. These areas show the greatest amount of tissue damage in the brains of autopsied alcoholics, according to prior research cited in the study. Cognitive tests were also performed, and spinal fluid was taken for analysis.

The MRIs and other test results indicated that "brain damage is detectable in heavy drinkers who are not in treatment and function relatively well in the community," Meyerhoff said. Light to moderate drinkers did not appear to have brain deterioration or impairment in functioning.

While the differences between the two categories were not large, Meyerhoff said some of the difficulties heavy drinkers may experience include an increase in how long it takes to retrieve memories, an inability to apply consequences to their past actions and difficulty working out abstract concepts.

The study was intended to focus on people who may be at a higher risk of becoming alcoholics, Meyerhoff said, but is not meant to turn people off of drinking.

"Our message is: Drink in moderation," he said. "Heavy drinking damages your brain ever so slightly, reducing your cognitive function in ways that may not be readily noticeable, [so] to be safe, don't overdo it."

For a comprehensive look at the potential health benefits of drinking wine, check out senior editor Per-Henrik Mansson's feature Eat Well, Drink Wisely, Live Longer: The Science Behind A Healthy Life With Wine

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