When drinking helps: sorting out for whom a nip might prove therapeutic

Science News, March 8, 2003 by Janet Raloff

Downing a cocktail or other alcoholic drink at least three to four times a week appears to substantially cut a man's risk of heart attack, Boston-area researchers reported in early January. Less than a week later, a U.S.-Canadian team of epidemiologists focusing on African Americans announced it had found no clear benefit to people drinking the same amount of alcohol per week. These reports joined other seemingly conflicting studies on the health impacts of alcohol that have emerged in the past few years.

Some research found that regular, moderate drinking not only helps preserve mental clarity in both young and elderly people but also increases blood-sugar control in people with diabetes. Other studies linked low but regular consumption of alcohol with an increased risk of certain cancers and a stunting of children exposed to alcohol in the womb. These subtle detrimental effects, of course, add onto the potentially catastrophic acute events caused by alcohol-impaired judgment.

With dozens of conflicting reports spilling out each year, is it any wonder that the public is confused about alcohol and health?

Yet, in probing the scores of published papers on alcohol's impacts, researchers have begun to discern a few trends. Chief among them: Alcoholic beverages can offer large pharmacological benefits, especially to people at elevated risk of heart disease. Various studies have begun unveiling why (SN: 1/5/02, p. 8).

In fact, argues Jurgen Rehm of the Centre for Addiction and Mental Health in Toronto, because alcohol's benefits appear primarily from slowing the progression of chronic diseases that usually emerge in or after middle age, there seems to be little health justification for drinking alcohol before age 40.

Among older adults, however, benefits of moderate drinking "appear to be huge," notes Tim Stockwell, director of the National Centre for Research into the Prevention of Drug Abuse at Curtin University of Technology in Perth, Australia. Data in his country indicate that among people who regularly down a few drinks a day, "there are approximately 6,500 lives saved each year by alcohol's protective effects on cardiovascular disease." Even factoring in alcohol-associated deaths from breast cancer and other malignancies, he says, "the net benefit for [moderate] drinking here appears to be about 5,000 lives a year."

"Although I think alcohol can be part of a healthy lifestyle, it's not a necessity" says Eric B. Rimm of the Harvard School of Public Health in Boston. Moreover, he adds, one wouldn't want to push abstainers to start drinking if they have cultural, religious, or other prohibitions against it--or an inability to hold their drinking to a few glasses per day. And drinking should never, he says, be portrayed as a substitute for exercise, eating a healthy diet, or giving up cigarettes as the best ways to stave off heart disease.

But among people who now drink occasionally, Rimm says, the accumulating evidence of alcohol's potential benefits is "so overwhelming that there are probably many cases where some people should be told to drink a little more."

RISKS IN ABSTAINING Alcohol is without question a poison. People die from binging, and many children enter the world with a retardation that traces to prenatal alcohol exposure. In fact, Rehm says, more than 60 diseases have been linked to excessive consumption of alcohol.

Although one might expect those risks to increase linearly with consumption, they don't. Stockwell points to hundreds of studies showing that a little daily drinking is more healthful than either abstaining or drinking to excess.

Epidemiologists refer to this as alcohol's "J-shape curve, for the contour that the risk data take when plotted on a graph. That provocative contour emerged strongly in a new review of 35 studies on stroke performed by researchers at Tulane University in New Orleans. In the Feb. 5 Journal of the American Medical Association, Kristi Reynolds and her colleagues confirm "a J-shaped association between alcohol consumption and the relative risk of ... ischemic stroke," a disorder that traces to blockages tn the brain's blood vessels.

Two years ago, Rehm and his colleagues reported a J-shape curve for alcohol consumption and premature deaths from all causes in their 11-year study of 5,200 U.S. men and women.

Economists at Duke University in Durham, N.C., published data 2 years ago showing a J contour in alcohol's impacts on disability claims. For 6 years, Jan Ostermann and Frank A. Sloan followed 12,650 people initially in their 50s or 60s. People drinking one or two drinks a day were least likely to report a disabling event, such as stroke or arthritis, "whereas abstainers generally were most likely to be disabled."

No matter how many possibly confounding factors they investigated, Sloan says, "we could not make the effect go away."

Rimm's team also observed a disadvantage for abstainers in a new 12-year study of heart-disease risks in 38,000 male health professionals. Overall, the researchers report in the Jan. 9 New England Journal of Medicine, disease risk fell as the volume of regularly consumed alcohol rose.