Moderate Drinking Guards the Heart
But protective effect can wear off at higher levels in men, study finds
THURSDAY, Nov. 19, 2009 (HealthDay News) -- A Spanish study has found that long-term moderate drinking decreased the risk of heart disease by up to one-third in men and to a lesser degree in women.
The type of alcohol -- beer, wine or spirits -- made no difference, the researchers reported in the Nov. 19 online issue of Heart. The Spanish analysis used 10-year data on 15,500 men and nearly 26,000 women who were participants in the European Prospective Investigation into Cancer study.
But for men, there was a point at which the coronary benefits of alcohol declined, and risk began to rise again.
The rate of coronary heart disease for non-drinking women in the study was 56 per 100,000. For women listed as low drinkers, averaging less than 5 grams a day, it was 42. For women who were moderate drinkers (5 to 30 grams a day), it was 36; for high drinkers (30 to 90 grams a day) it was 12; and for heavy drinkers (more than 90 grams a day) it was 12.
The rates for men were 398 per 100,000 for those who never drank, 318 for low drinkers, 255 for moderate drinkers, 278 for high drinkers and 334 for heavy drinkers, the researchers reported.
The results for women were not statistically significant, perhaps because the numbers in many categories were too small, said the report from the Public Health Department of Gipuzkoa, Basque Government, in San Sebastian.
The finding comes as no surprise, said Eric B. Rimm, an associate professor of epidemiology and nutrition at the Harvard School of Public Health, who has done research on alcohol and heart disease.
"This is one of a long line of such studies, probably 60 or 70 done in different populations around the world," Rimm said. "But it is comforting, showing that even if you live in a Mediterranean country and eat the different diet there, moderate drinking puts you at a much lower risk of heart disease."
The report showing that the source of alcohol made no difference does help puncture one explanation for what has come to be called the "French paradox," the low level of heart disease seen in that country despite consumption of what Americans would describe as an unhealthy, fat-rich diet, Rimm said. Some experts have attributed the paradox to the beneficial effects of red wine.
Instead, it is just alcohol in general, Rimm said. "A number of well-done studies have shown that people who drink have higher levels of HDL cholesterol," he said. "In a week or two of drinking, HDL cholesterol goes up appreciably."
HDL cholesterol is the "good" kind that prevents formation of artery-blocking plaque deposits.
The newly reported study, like all others on the issue of alcohol and the heart, is observational, with no attempt at controlling intake, noted Dr. Kenneth Mukamal, an internist at Beth Israel Deaconess Hospital and an associate professor of medicine at Harvard Medical School.
"I don't think it's substantially different from what we've seen before," Mukamal said. "We've probably pushed the observational data as far as we can."
So Mukamal has obtained funding from the U.S. National Institute on Alcohol Abuse and Alcoholism for a pilot project to determine if a controlled trial of the effects of alcohol on the heart is possible. He and his colleagues are enrolling 40 adults who will try to drink exact amounts of either alcohol or an alcohol-free beverage daily for six months.
"We're hoping to see over time what differences there are in those assigned to the nonalcoholic and those assigned to the alcoholic beverages," Mukamal said. Most important, the study will show whether people can stick to such a regimen for a prolonged period. Results of the pilot project should be available in about a year, Mukamal said, and those results will help determine whether a longer, larger trial is possible.
Meanwhile, it's important to remember that "clearly, heart disease is not the only thing to consider when you talk about drinking alcohol," Rimm said. Overindulgence raises the risk of cancer, accidents, obesity and many other problems, and can also cause the heart muscle damage called alcoholic cardiomyopathy, he noted.
The American Heart Association recommendation is that "if you drink, do so in moderation." That means one to two drinks a day for a man, one drink a day for a woman, with a drink defined as 12 ounces of beer, 4 ounces of wine or 1 ounce of 100-proof spirits.
Guidance on alcohol and the heart is offered by the American Heart Association.