How many drinks provide just the benefits and not the harm? It depends on whether a person is most at risk of heart disease, diabetes or breast cancer. But there is one bottom line: Five or six drinks only on Saturday night will provide no benefits, while a drink or two a night might.
So concludes an exhaustive new analysis by the National Institutes of Health that sorts out a plethora of sometimes conflicting research on alcohol's effects.
The review was prompted by cardiologists' complaints that patients suddenly were asking if they should start imbibing, and how much. Other research is overturning the dogma that people at risk of diabetes should abstain; still more links even light drinking to breast cancer.
Adding confusion, people are vulnerable to more than one disease as they age. A 50-year-old woman with breast cancer in the family might get very different advice on alcohol than one who's pre-diabetic with high cholesterol.
Hence NIH's review.
"We are not encouraging anybody to start drinking," stresses Lorraine Gunzerath of the NIH's National Institute on Alcohol Abuse and Alcohol, who led the analysis published last month in the journal Alcoholism: Clinical & Experimental Research.
After all, alcoholism remains a major health problem, and people with liver disease may not tolerate even moderate drinking.
Instead, the report, aimed at people who already drink some, concludes that to get alcohol's potential health benefits, how much those people can consume must be customized by their age, gender and overall medical history.
For many of these diseases, "If you do drink moderately now, fear ... is not a reason to stop," explains Gunzerath. "Some people have said, `Should I stop now because there's diabetes in my family?' Well, if you're a moderate drinker, there's some protection."
As population-wide advice, consuming two drinks a day for men and one a day for women is linked to lower mortality and unlikely to harm, the review found. Men shouldn't exceed four drinks on any day, and women three - bingeing is simply bad.
But NIH's disease-by-disease findings provide better details:
However, frequency seems key. Consuming smaller amounts several times a week - one or two daily or every other day - is most heart-protective. It apparently takes low, regular alcohol exposure to help raise levels of the body's so-called good cholesterol, the HDL type, and to thin blood.
But women whose mothers or sisters had breast cancer, or those taking post-menopausal estrogen replacement, are at greater risk from alcohol. Those women, Gunzerath says, must weigh the fear of breast cancer against their risk of heart disease in deciding whether to avoid alcohol.
Low levels of alcohol apparently help the body use insulin to process blood sugar better. The benefit was seen among the overweight and those with "metabolic syndrome," a cluster of pre-diabetic weight-related symptoms that include high blood pressure and poor cholesterol.
How much is a drink a day? Five ounces of wine, 12 ounces of beer or 1.5 ounces of distilled spirits. To help people add that up, consumer groups are pushing for alcohol containers to list serving sizes and the moderate-drinking advice; the Alcohol and Tobacco Tax and Trade Bureau hasn't yet responded.
By Lauran Neergaard