“We know certainly vitamin D is important for bone,” Dr. Jenny Kim said. But can this vitamin decrease the risk for some cancers?
“We are reading this everywhere — there is a lot of hype. Is there any correlation?” Dr. Kim asked at a seminar on women’s and pediatric dermatology sponsored by the Skin Disease Education Foundation (SDEF).
The strongest evidence comes from multiple studies of adenoma or colorectal cancers, where researchers linked
higher levels of 25-hydroxyvitamin D (25D) to a lower risk for these malignancies (for example, a 2004 study in the International Journal of Cancer and a 2003 report from the Journal of the National Cancer Institute).
A target serum vitamin 25D concentration of 100 nmol/L may be optimal for colorectal cancer prevention, these studies indicate, said Dr. Kim, Chief of the Department of Dermatology at the Greater Los Angeles Healthcare Systems VA and Associate Professor of Dermatology at David Geffen School of Medicine.
Vitamin D may tromp some other cancers as well. For example, dietary vitamin D intake prevented an increase in obesity-related endometrial cancer in a new animal study released this month (September 2010).
So is there any official word? A fact sheet from the National Cancer Institute (NCI) states “some studies suggest that higher intakes of vitamin D from food and/or supplements and higher levels of vitamin D in the blood are associated with reduced risks of colorectal cancer; however, the research results overall have been inconsistent.” The NCI adds that it is unclear whether vitamin D is associated with reduced risk for other cancer types.
So it looks promising, but time — and more decisive data — will tell. In the meantime, Dr. Kim recommended dermatologists measure vitamin D levels and encourage patients to increase dietary and supplement sources as indicated.
Beneficial effects on blood pressure, immunity, and prevention of infections such as tuberculosis are other active areas of vitamin D research, Dr. Kim said.
Dr. Kim disclosed she is on the scientific advisory board for Steifel, a GlaxoSmithKline company.
The Skin Disease Education Foundation and the dermatology publication for which I report, Skin & Allergy News, are owned by Elsevier.
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