Supplements of calcium and vitamin D may promote the health of the cells in the colon and rectum, offering potential protection from tumor development.

Researchers conducted a randomized, double-blind, placebo-controlled clinical trial in nearly 100 men and women with a history of benign colorectal tumors. Participants received daily calcium supplements, vitamin D3 supplements, a combination of both, or a placebos.

Markers of the health of cells were found to increase in the calcium, vitamin D, and calcium plus vitamin D groups relative to the placebo.