A. Katherine L. Tucker, PhD, a professor at the University of Massachusetts-Lowell and adjunct professor at Tufts Friedman School, answers: It has long been thought that alcohol is bad for bones, and it is clear that very heavy alcohol consumers have higher risk of osteoporosis. However, the evidence does not support that for moderate consumers. Most studies show that moderate alcohol consumers have higher bone mineral density (BMD) than non-consumers, but that there is an inverse U-shaped curve, with lower BMD for high consumers.
A 2009 Tufts study by Tucker and colleagues, for example, concluded, The positive relation between intake of alcohol and BMD in men and postmenopausal women, the reproducibility of these effects across the different bone sites, and the consistency of these findings with other published studies of total alcohol intake suggest that alcohol intake, particularly from beer and wine, may protect bone health. However, intake of more than two drinks per day of liquor in men was clearly harmful.
These apparent beneficial effects, Tucker adds, are thought to be related to the estrogenic effects of alcohol itself, polyphenolics in wine or beer, and silicon in beer.