Risk of Prostate Cancer Increased by Calcium Intake

A new study has found that high calcium intake, especially from dairy products, may increase the risk of prostate cancer. The study was published in the October 2001 issue of the American Journal of Clinical Nutrition.

Researchers investigated the connection between diary products, calcium consumption, and prostate cancer in a group of 20,885 male physicians. Men in the highest quintiles of dairy product consumption had a significant 34% greater risk of prostate cancer when compared to those in the lowest categories. When calcium intake was examined apart from dairy product consumption, the risk ratio was 30% higher for advanced prostate cancer and 47% higher for non-advanced cases. Of all dairy products, only skim milk was positively associated with prostate cancer risk, maybe because it accounted for 48% of total consumption of dairy foods.

The authors propose that the dietary calcium increases prostate cancer risk by suppressing the production of 1,25-dihydroxyvitamin D3, the most active form of vitamin D, thought to protect against this disease. Examination of vitamin D metabolites in a subset of the study population revealed that those with the highest quintile of calcium consumption
(> 600 mg/day) had 17% lower serum concentrations of 1,25-dihydroxyvitamin D3 than those in the lowest quintile of calcium consumption (< 150 mg/day). Previous studies limited to supplemental calcium consumption have demonstrated similar risk ratios.

The authors conclude that "These findings may serve to inject a note of caution into the current enthusiastic promotion of a higher intake of calcium in the United States.”




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American Journal of Clinical Nutrition