The jury is still out on calcium

Physicians and researchers have long believed that consuming high amounts of calcium and dairy products increases the risk of prostate cancer, although study results have been inconsistent. Two recent studies make clear that the jury is still out.

A study of 29,133 men in Finland found that those who consumed 2,000 mg of calcium or more daily had a marked increase in prostate cancer risk. High consumption of dairy foods was also associated with an increased risk of the disease, which the researchers attributed to the calcium (or a closely related component) in those foods.

The National Institutes of Health–AARP Diet and Health Study came to a somewhat different conclusion. Researchers reported in December 2007 that a total calcium intake of 2,000 mg or more was associated with advanced prostate cancer, although the link was not considered statistically significant. In contrast, they found that calcium from nondairy foods actually seemed to lower prostate cancer risk.

Although the debate continues, men might want to keep calcium consumption well below 2,000 mg a day, the threshold at which both studies found an increased incidence of prostate cancer.

SOURCES: Mitrou PN, Albanes D, Weinstein SJ, et al. A Prospective Study of Dietary Calcium, Dairy Products, and Prostate Cancer Risk (Finland). International Journal of Cancer 2007;120:2466–73. PMID: 17278090.

Park Y, Mitrou PN, Kipnis V, et al. Calcium, Dairy Foods, and Risk of Incident and Fatal Prostate Cancer: The NIH-AARP Diet and Health Study. American Journal of Epidemiology 2007;166:1270–79. PMID: 18000020.