People who enjoy a glass or two of wine or beer every day could be helping to keep their bones strong, new research published in the American Journal of Clinical Nutrition suggests.

However, drinking more - and choosing hard liquor instead of wine or beer - may actually weaken bones, Dr. Katherine Tucker of Tufts University in Boston and her colleagues found.

In an interview with Reuters Health, Tucker agreed that keeping track of the health benefits and risks of alcohol is tough these days. “It is very confusing for people because alcohol has such diverse effects on different things,” she said; for example, while drinking may prevent heart disease, it increases breast cancer risk.

Nevertheless, the researcher added, the effect of alcohol on bone mineral density (BMD) that she and her colleagues saw was “larger than what we see for any single nutrient, even for calcium. It’s not ambiguous. It’s very clear.”

In the current study, Tucker and her team investigated how different types of alcohol affected bone density in 1,182 men, 1,289 postmenopausal women, and 248 premenopausal women participating in the Framingham Offspring study. Study participants ranged in age from 29 to 86.

Men who had a glass or two of wine or beer daily had denser bones than non-drinkers, the researchers found, but those who downed two or more servings of hard liquor a day had significantly lower BMD than the men who drank up to two glasses of liquor daily.

The women who drank more than two glasses a day of alcohol or wine had greater BMD than the women who drank less. Nonetheless, this finding shouldn’t be seen as meaning that the more a woman drinks the better it is for her bones, Tucker noted; there were simply not that many women in the study who drank much more than this.

Beer is an excellent source of silicon, a mineral needed for bone health that has become increasingly rare in the modern diet, the researcher noted. Beer’s silicon content accounted for at least some of its bone-building effects in men, she added; there were too few women who drank beer to draw conclusions about how the mineral affected female bone density.

Beer and wine may be better for people than liquor, she suggested, because they contain potentially beneficial plant substances such as resveratrol, while hard liquor has had most natural substances distilled out of it.

It’s likely, Tucker said, that alcohol may help build bones by boosting estrogen levels - which is the mechanism that also may account for the increased breast cancer risk seen for women who drink even moderately.

“The main message here is that if you are drinking up to one or two glasses of wine or beer a day, you don’t need to stop for your bones’ sake, in fact it’s helpful,” the researcher said. “It’s a personal decision.”

SOURCE: American Journal of Clinical Nutrition, online February 25, 2009.