Study: Vitamin D, Calcium Work Together to Cut Colorectal Cancer Risk

The nutrients calcium and vitamin D work in tandem to reduce the risk of colorectal cancer, according to a new study reported in the New England Journal of Medicine.

Their study involved a four-year follow-up of 832 patients who had polyps removed. Doctors consider polyps in the colon strong precursor to colorectal cancer.

The researchers reported that 31 percent of the study patients who received 1200 milligrams of calcium carbonate daily developed one or more polypsm compared to 38 percent of the volunteers who received a placebo.

"In the treatment group, we found overall a 24 percent decrease in the number of polyps and a 19 percent decrease in the risk of recurrence," said Dr. Robert Sandler, professor of medicine at the University of North Carolina at Chapel Hill School of Medicine. "This represents a significant, although moderate, reduction in the risk of recurrent colon adenomas."

The researchers said their analysis also found that calcium supplements prevented polyps only among individuals with higher-tnah-average vitamin D levels, and said vitamin D was only linked to reduced polyp recurrence among individuals taking calcium supplements.

These findings "provide a strong indication that vitamin D and calcium have a joint antineoplastic effect in the large bowel," but are essentially ineffective without the other, the researchers added.

They concluded that "further investigation is needed to understand the mechanistic basis of the vitamin D/calcium interaction and to clarify the amount of intake of each nutrient required for optimum protective effect."

Other sources: New England Journal of Medicine