Men who consume more than 600 milligrams (mg) of calcium per day from dairy products may have as much as a 32 percent higher risk of prostate cancer than men whose calcium intake from dairy sources is low. According to a study published in the October 2001 issue of the American Journal of Clinical Nutrition, a high intake of dairy products and calcium may increase prostate cancer risk by lowering concentrations of the hormone 1,25-dihydroxyvitamin D3, which is thought to protect against prostate cancer.
More than 20,000 men enrolled in the Physicians’ Health Study answered abbreviated dietary questionnaires. During 11 years of follow-up, 1,012 cases of prostate cancer were documented. Researchers found that men who consumed more than 600 mg of calcium from skim milk had a lower concentration of the hormone than did those who consumed 150 mg or less of calcium from dairy sources.