The relationship between vitamin D and cancer.

Vitamin D, a fat-soluble vitamin naturally present in very few foods, is synthesized when ultraviolet rays from sunlight contact the skin. Research suggests that vitamin D insufficiency may result from lack of exposure to sunlight and ultraviolet-B radiation. Individuals from geographic areas of high latitude and low sunlight exposure may be at increased risk for vitamin D deficiency. Emerging evidence supports the protective role of vitamin D in the prevention of several cancers, including breast, colon, and prostate.