Vitamin D deficiency can increase cancer risk (Reuters)

NEW YORK (Reuters Health) - Correcting vitamin D deficiency could significantly lower the risk of several types of cancer, investigators report. "The cost of a daily dose of vitamin D3 (1000 IU) is less than 5 cents, which could be balanced against the high human and economic costs of treating cancer attributable to insufficiency of vitamin D," they point out.

Vitamin D can reduce the risk of many types of cancer by block the growth of new blood vessels that allow cancer to thrive, a process known as angiogenesis.

It can also stimulate cell adherence and "enhance intercellular communication through gap junctions, thereby strengthening the inhibition of cancer cell growth that results from tight physical contact with adjacent cells within a tissue," Dr. Cedric F. Garland and colleagues note in their article, published in the current issue of the American Journal of Public Health.

Garland, from the University of California, San Diego in La Jolla, and his colleagues performed a search of published studies, identifying 63 observational studies on vitamin D and its association with cancers of the colon, breast, prostate and ovary.

Twenty of 30 studies of colon cancer or precancerous colon polyps found a statistically significant benefit of vitamin D. Similar results were observed for 9 of 13 studies concerning breast cancer risk, 13 of 16 studies concerning prostate cancer risk, and 5 of 7 studies concerning ovarian cancer.

The authors recommend supplementing the diet with 800 to 1000 IU vitamin D per day, and believe that dosages up to 1000 IU per day would not produce toxicity.

SOURCE: American Journal of Public Health, February 2006.