Study: Vitamin D May Provide Some Protection Against Colon Cancer

Researchers report they have found that vitamin D may provide some protection against the increased risk of colon cancer associated with a high fat diet.

Dr. David J. Mangelsdorf of the University of Texas Southwestern Medical Center in Dallas, reporting in Science, said the link between vitamin D and colon cancer appears to be the response of the vitamin D receptor found in the intestine to levels of lithocholic acid.

Under normal conditions, lithocholic acid -- a bile acid produced when fat breaks down -- is mildly toxic.

When vitamin D levels are adequate, the vitamin D receptor responds by producing the cytochrome P450 enzyme, CYP3A, which breaks down the lithocholic acid.

But vitamin D levels are low, or when excess fat stimulates an overproduction of lithocholic acid, the vitamin D receptor's action is overwhelmed and lithocholic acid builds up to toxic levels, the researchers said.

Despite the apparent linkage between vitamin D and colon cancer, the researchers emphasized that it would be foolhardy for people to simply take more vitamin D in an effort to offset the increased risk posed by a high-fat diet, since high doses of vitamin D can lead to hypercalcemia, a serious metabolic disorder.

Other sources: Science