Tuesday June 3, 2014 (foodconsumer.org) -- Biochemical and epidemiologic studies reveal evidence to suggest calcium intake protects against incident colorectal cancer and clinical trials show calcium prevents adenomas, a precursor to colorectal cancer, according to a review in International Journal of Cancer.

A review of prospective studies published prior to Dec 2013 in major databases including PubMed, Embase, and BIOSIS shows evidence is consistent and strong that suggests high intake of dietary calcium or supplemental calcium was associated with reduced risk of colorectal cancer.

Specifically, each 300 mg of total calcium per day increase was associated with an 8 reduced risk of colorectal cancer.  The finding was based on 15 studies of 12,305 cases of colorectal cancer who had 250 to 1,900 mg of calcium per day and were followed for 3.3 to 16 years.

For supplementary calcium, each 300 mg per day increase was correlated with a 9% reduced risk of colorectal cancer. The finding was based on six studies of 8,839 cases who had 0 to 1,150 mg of calcium per day and were followed for 5 to 10 years.

The study concluded "both dietary and supplementary calcium intake may continue to decrease CRC (colorectal cancer) risk beyond 1,000 mg/day."

Some studies suggest that taking calcium supplements may increase risk of heart disease.  But recent studies suggest taking calcium supplements does not increase the risk. (David Liu, PHD)

Reference

Keum N, Aune D, Greenwood DC, Ju W, Giovannucci EL.   Calcium intake and colorectal cancer risk: Dose-response meta-analysis of prospective observational studies. International Journal of Cancer. 2014 Mar 13.86.