Calcium supplementation may offer prostate cancer protection

US clinicians have found some evidence to suggest that calcium supplements may help protect men against the development of prostate cancer.

Noting that a high calcium intake has been linked to prostate carcinogenesis, the team examined data from 672 men participating in a colorectal adenoma chemoprevention trial who were randomly assigned to receive daily supplementation of 3 g of calcium carbonate (1200 mg calcium) or placebo for 4 years.

Maria Grau ( Dartmouth Medical Center , Lebanon , New Hampshire ) and co-workers followed-up the participants for an average of 10.3 years. During this time, 33 calcium-treated men and 37 placebo-treated individuals were diagnosed with prostate cancer (rate ratio [RR]=0.83).

Indeed, further analysis showed that up to 2 years after the intervention ended, there was significantly fewer cases of prostate cancer in patients given calcium than controls, with a RR of 0.52.

Of note, serum samples collected at randomization and after 4 years showed that the RR of calcium-treated individuals having prostate-specific antigen levels that converted to above 4.0 ng/ml was 0.63.

Baseline measurements of dietary calcium, 1,25-(OH)2 vitamin D, and 25-(OH) vitamin D, however, did not correlate with risk of prostate cancer.

Writing in the journal Cancer Epidemiology Biomarkers and Prevention , the team concludes: "In this randomized controlled clinical trial, there was no increase in prostate cancer risk associated with calcium supplementation and some suggestion of a protective effect."