Vitamin D May Protect against a Wide Variety of Cancer Types
Widespread supplementation with vitamin D may save thousands of lives per year in the Unites States, according to a study published this month in the journal Cancer.1
The author of this study correlated the mortality rate from different types of cancers with the amount of solar ultraviolet (UV) light exposure in over 400 areas of the country. This analysis revealed a significant association between lack of UV light and increased risk of several different types of cancer, including breast, prostate, colon, ovary, bladder, esophageal, kidney, lung, pancreatic, stomach, uterine, and non-Hodgkin’s lymphoma.
Using these statistics and the national cancer mortality rate, the author estimated that insufficient exposure to UV light was responsible for 21,700 premature cancer deaths in the white population, 1,400 for black Americans, and 500 for Asian Americans and other minorities.
The most plausible explanation for the association between UV exposure and cancer risk involves vitamin D deficiency. Humans manufacture vitamin D upon exposure to sunlight. For this reason, vitamin D deficiency is a particular risk in people living in northern latitudes.
Many researchers have found potentially cancer-preventing actions of vitamin D.2 3 4 There is also some evidence that vitamin D is beneficial in the treatment of some cancers.5 6 7
There are some potentially important drawbacks to this new study, however. For example, solar radiation was measured during only two months of the year, and no information was obtained about dietary intake of vitamin D. These and other factors could introduce varying degrees of error into the results. Even more importantly, there are other potential reasons that certain areas with less sunlight tend to have higher rates of cancer. For example, the highest rates of many common cancers were seen in the northeastern part of the country. In addition to having low sunlight exposure in the winter months, this area tends to be one of the most heavily industrialized—and, therefore, heavily polluted—in the country. While there is certainly good circumstantial evidence that vitamin D protects against cancer, this study is by no means the final word.
Although additional studies are needed to confirm the role of vitamin D supplementation in cancer prevention, it would be a logical addition to a cancer-prevention program, particularly for people living in northern latitudes. Since the safety of vitamin D supplementation up to at least 2,000 IU per day is well established,8 the benefits of vitamin D supplementation are likely to outweigh the risks.
1. Grant WB. An Estimate of Premature Cancer Mortality in the U.S. Due to Inadequate Doses of Solar Ultraviolet-B Radiation. Cancer 2002;94:1867–75.
2. Lamprecht SA, Lipkin M. Cellular mechanisms of calcium and vitamin D in the inhibition of colorectal carcinogenesis. Ann N Y Acad Sci 2001;952:73–87.
3. Lipkin M, Newmark HL. Vitamin D, calcium and prevention of breast cancer: a review. J Am Coll Nutr 1999;18(5 Suppl):392S–397S.
4. Giovannucci E. Dietary influences of 1,25(OH)2 vitamin D in relation to prostate cancer: a hypothesis. Cancer Causes Control 1998;9:567–82.
5. Van Veldhuizen PJ, Taylor SA, Williamson S, Drees BM. Treatment of vitamin D deficiency in patients with metastatic prostate cancer may improve bone pain and muscle strength. J Urol 2000;163:187–90.
6. Gross C, Stamey T, Hancock S, Feldman D. Treatment of early recurrent prostate cancer with 1,25-dihydroxyvitamin D3 (calcitriol). J Urol 1998;159:2035–9.
7. Ferrero D, Bruno B, Pregno P, et al. Combined differentiating therapy for myelodysplastic syndromes: a phase II study. Leuk Res 1996;20:867–76.
8. Vieth R. Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety. Am J Clin Nutr 1999;69:842–56.
Matt Brignall, ND, is in practice at the Seattle Cancer Treatment and Wellness Center and at the Evergreen Integrative Medicine Clinic in Kirkland, WA. He specializes in integrative treatment of cancer. He is a contributor to Healthnotes and Healthnotes Newswire.
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