Calcium, extra weight protect women from bone loss

NEW YORK (Reuters Health) - Women in early menopause who consume less calcium are at greater risk of osteoporosis than their peers who take in more of the mineral, Italian researchers report.

But the fact that these women are also more likely to be overweight, and thus have denser bones, may help protect them from the brittle bone disease, Dr. Massimo Varenna and colleagues from the University of Milan found.

Nevertheless, "given our current knowledge, it is probably unwise to offer the choice between drinking milk and gaining weight for protection against bone loss," Drs. Connie M. Weaver and Stacey L. Mobley of Purdue University in West Lafayette, Indiana, write in an editorial accompanying the study.

"Most individuals," they note, "would more likely benefit from the consumption of 3 servings of dairy products daily as recommended by the Dietary Guidelines for Americans to protect against bone loss and to possibly manage healthy body weight."

Varenna and his team investigated how calcium intake and body weight might affect osteoporosis risk among women shortly after menopause. They evaluated bone density in 1,771 women who weren't taking calcium supplements, estimating their calcium intake by determining how often they ate dairy foods.

The more dairy the women consumed, the less likely they were to be overweight, and their average body mass index or BMI -- a measure of weight in relation to height -- dropped as calcium intake rose.

The researchers found no link between osteoporosis and calcium intake when they didn't take excess weight into account, but when they did, they found that women who consumed the least calcium were 46 percent more likely to have osteoporosis than those who consumed the most.

The findings, Varenna and his colleagues say, suggest that the greater likelihood of being overweight they found among the lowest calcium consumers could help protect them from osteoporosis. "Because the aim in these women is to prevent, rather than to treat, osteoporosis and safer alternatives to estrogen need to be sought, an adequate understanding of the role of potentially modifiable lifestyle factors such as nutrition must be addressed further," they conclude.

SOURCE: American Journal of Clinical Nutrition, September 2007.