Vitamin D and Cancer Prevention
Marcellino D’Ambrosio, Ph.D.
Correcting vitamin D deficiency could significantly lower the risk of several types of cancer according to recent findings by researchers from the University of California, San Diego in La Jolla. “The cost of a daily dose of vitamin D3 (1000 IU) . . . could be balanced against the high human and economic costs of treating cancer attributable to insufficiency of vitamin D,” the scientists point out.
How can Vitamin D reduce the risk of many types of cancer? It appears to block the growth of new blood vessels that allow cancer to thrive, a process known as angiogenesis.
Vitamin D 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 February 2006 issue of the American Journal of Public Health.
Dr. Garland 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. This is significantly more than the current recommended daily allowance (RDA) of 600 IU.
So how do you get the needed vitamin D for strong bones and cancer prevention?
Vitamin D can be produced in the body by exposure of the skin to sunlight, but most of us don’t get regular sunlight each day of the year and if we did, the UV rays could pose a problem. A cup of milk only supplies about 150 mg, so if milk is your sole source of vitamin D, plan to drink 7 cups of milk daily. For most people, it would seem that a comprehensive approach is a good idea—some moderate sunlight, several servings of dairy a day and either a vitamin D supplement or high quality multi-vitamin that contains vitamin D.
SOURCE: American Journal of Public Health, February 2006.
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