Some people worry that if they use sunscreen it will cancel out their body’s ability to absorb vitamin D from the sun. Here, the controversy is between those who feel that exposing our skin to the sun without sunscreen is dangerous, versus those who believe that sunscreen will cancel out the body’s ability to manufacture vitamin D from sun exposure. This concern over sunscreen has been expressed in the pages of several reputable resources. (Sources: Photochemistry and Photobiology, March-April 2007, pages 459-463; American Journal of Clinical Nutrition, December 2004, pages S1678— 1688S; and Archives of Dermatology, December 1988, pages 1802—1804.)
There are mixed opinions on this one (I know, it’s always complicated). Regarding this issue, a June 1999 article in Cosmetic Dermatology (page 43) discussed a presentation given by Mark Naylor, MD, assistant professor in the Department of Dermatology at the University of Oklahoma, which described some research on use of sunscreen: “Prospective sunscreen trials examining whether sunscreen contributes to vitamin D deficiency found that regular sunscreen users were not vitamin D deficient.” Other research has echoed that assertion. (Source: Journal of Photochemistry and Photobiology, December 2007, pages 139—147.)
There is also the issue that no sunscreen, regardless of its active ingredients or how often or liberally it is applied, can provide 100% protection from UV radiation. The tiny amount of UVB light that sunscreens do not shield us from is enough to begin the synthesis of vitamin D, although—depending on your skin color, environment (how much daily sunshine is there), and climate—supplemental vitamin D will likely still be necessary.
There is no question that we need vitamin D, either from the sun or supplementation, because research has found a large percentage of the population is deficient in vitamin D, especially as we age. If skin wrinkles, premature aging of the skin, and skin cancers are an issue for you, then the answer is clear: you need to do both—diligently protect your skin from the sun and take a vitamin D supplement.
(Additional sources for the above: The Journal of the American Osteopathic Association, August 2003, pages 3-4; American Journal of Clinical Dermatology, March 2002, pages 185-191; Dermatology, January 2001, pages 27-30; British MedicalJournal, October 1999, page 1066; and Archives of Dermatology, April 1005, pages 415-421).
Note: Before beginning any new vitamin supplement program, make sure to consult your physician.