A review study by Israeli researchers, reports that, at the moment, there is insufficient evidence to support the conclusion that calcium lowers the risk of colorectal cancer, one of the leading cancers in both men and women.
The review of two previous studies of 1,300 people showed that calcium may hinder the development of colorectal polyps that lead to cancer, but not necessarily the cancer itself. Small, benign polyps are reported in about thirty percent of middle aged and elderly Americans.
Although earlier research had suggested that a high-calcium diet might prevent colorectal cancer, the current evaluation concluded that “this does not constitute sufficient evidence to recommend the general use of calcium supplements to prevent colorectal cancer.” The conclusions are published in the most recent issue of the journal The Cochrane Library.
However, one of the review doctors, Anca Zalmanovici, stated that calcium supplements could still be beneficial. “Calcium supplementation is relatively cheap, likely to be safe, readily available and has other positive metabolic effects on conditions that occur with aging.” These include the prevention of osteoporosis, high blood pressure, kidney stones, and weight gain
If subsequent studies demonstrate calcium can help prevent colorectal cancer, this might lead to the administration of calcium supplements to those with a history of polyps.
The U.S. National Cancer Institute provides more information about preventing colorectal cancer.