BOSTON - The biggest study ever of the health effects of alcohol concludes that a drink a day can cut your risk of death by about 20 percent.
Many studies over the past two decades have shown that a little alcohol is good for the heart. However, others have found an increased risk of breast cancer and other diseases.
The latest research, conducted by the American Cancer Society, attempts to add up the pluses and minuses and calculate the net effect of alcohol on health.
Like most other studies, this one found that modest drinking is, on balance, healthful. The ill effects, including cancer, are greatly offset by alcohol's benefits to the heart.
"The best advice to the public is, nothing in excess," said Dr. Michael J. Thun, the study's lead author.
The researchers gave questionnaires to 490,000 men and women and then followed up nine years later, after 46,000 of them had died. The findings were published in Thursday's issue of the New England Journal of Medicine.
Among the results:
- Men and women who averaged one drink a day had a 21 percent lower risk of death than did nondrinkers.
- The benefits decreased as people drank more. Among those who averaged four or five drinks a day, the risk of death among men was 10 percent lower, while among women it was 7 percent lower.
- Women who consumed at least one drink a day had a 30 percent higher risk of dying from breast cancer than did nondrinkers. Drinkers also faced a higher risk of dying from cirrhosis, alcoholism and cancer of the mouth, throat and liver.
- Overall, drinkers had about a 30 percent to 40 percent lower risk of dying of cardiovascular disease than did teetotalers.
Those who got the biggest benefit from drinking were people who clearly had bad hearts.
"It shows that the net effect of alcohol consumption on overall mortality is influenced not only by how much people drink but also by their background health risk," Thun said.
Alcohol appears to protect the heart by raising levels of HDL, the good variety of cholesterol, and it may have other beneficial effects on the circulatory system, as well.
Until now, two of the largest studies to look at this question were the Harvard-based Nurses Health Study and the Physicians Health Study. They found that moderate drinking lowers women's risk of death by 17 percent and men's by 22 percent.
An editorial by Dr. John D. Potter of Fred Hutchinson Cancer Research Center in Seattle noted that men in the latest study averaged one drink a day, while women consumed less than one. This is less than half what Americans typically consume.
If the general population drank more like these people did, Potter wrote, "we would see more of the benefits and less of the harm associated with alcohol."