Light Drinking Good for the Heart
Two studies confirm previous evidence that it reduces mortality
By Ed Edelson
Two major studies confirm the current medical consensus that moderate drinking appears to be good for the heart but heavy drinking is bad for health in general.
"This would not change our current guidelines, which provide an upper limit and not a lower limit, no more than two drinks a day for men and no more than one drink a day for women," said Dr. Kenneth J. Mukamal, an associate professor of medicine at Harvard Medical School and an internist at Beth Israel Deaconess Medical Center. He is lead author of one of the reports published online March 23 in the Journal of the American College of Cardiology.
The new study, using data from nine National Health Interview Surveys done between 1987 and 2000, is more thorough than previous reports and provides "some of the strongest evidence to date" of a link between moderate drinking and a lower risk of cardiovascular disease, Mukamal said.
Specifically, the study tries to separate out the health effects of people who list themselves as abstainers, some of whom have never touched the stuff and others who were heavy drinkers but gave it up because of possible damage to their health.
"Some studies have done better than others at that, but this is by far the largest effort to do it," Mukamal said. "We have data on more than 2 million person-years, appropriately weighted so that it is representative of Americans over the last 20 years."
The study looked specifically at deaths from cardiovascular conditions such as heart attack and stroke. It found a lower rate of such deaths in light and moderate drinkers than among people who never drank or quit. The type of alcoholic beverage -- beer, wine, liquor -- made no difference.
"Indeed, the lowest rate of cardiovascular mortality was among those who drink moderately," Mukamal said. "That benefit is clearly eliminated in people who drank above that level."
The results "dovetail nicely" with those of previous reports, but "they are not likely to lead to any recommendation to drink alcohol," Mukamal said, since drinking can have adverse effects on organs outside the cardiovascular system.
A second report in the same issue of the journal by Italian doctors and epidemiologists at Catholic University, in Campobasso, looked at the relationship between alcohol consumption and death rates in eight studies that included more than 29,000 drinkers and nondrinkers who had cardiovascular disease.
Moderate alcohol intake had a protective effect for those people, the report said. It found the maximum reduction in risk of death from all causes among those whose alcohol intake ranged from 5 to 10 grams a day. (A typical drink is usually defined as containing 13.7 grams of alcohol.)
For cardiovascular deaths alone, the maximum protective effect -- a 22 percent reduction -- was found for a daily intake of 25 grams of alcohol. The death rate went up with higher daily alcohol intake levels.
Their bottom line: "In patients with cardiovascular disease, light to moderate alcohol consumption (5 to 25 grams per day), was significantly associated with a lower incidence of cardiovascular and all-cause mortality."
But it's important to remember that advice about drinking should be made on the basis of a person's specific risk factors, said Dr. Arthur L. Klatsky, a senior consultant in cardiology at the Kaiser Permanente Health Plan in California, who wrote an accompanying editorial.
For example, there is no net benefit of moderate drinking for young women, since it increases the risk of breast cancer, Klatsky said, but the cardiovascular benefits for middle-aged men and women are there.
"Advice about this has to be given on an individual basis," he said.
SOURCES: Kenneth J. Mukamal, M.D., associate professor, medicine, Harvard Medical School, and internist, Beth Israel Deaconess Medical Center, Boston; Arthur L. Klatsky, M.D., senior consultant, cardiology, Kaiser Permanente Health Plan, Oakland, Calif.; March 23, 2010, Journal of the American College of Cardiology, online