The media-emphasized main conflict surrounding this
vitamin (which is actually a hormone, not a vitamin) revolves
around sun exposure and whether or not using sunscreen
hinders our bodies' ability to manufacture vitamin D.
Vitamin D deficiency can be a serious health problem and
sunlight can be the most abundant, natural way for our
bodies to create it. But can our bodies utilize the sun
to create vitamin D if we regularly use sunscreen? The
answer is a resounding yes. Despite news stories to the
contrary, several large, controlled studies have shown
that vitamin D deficiency does not result from ongoing
regular sunscreen use. Aside from sun exposure, vitamin
D supplementation is still a good idea because even with
sun exposure we can still be deficient. (Sources: 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; and British Medical Journal, October 1999,
page 1066).
You may be wondering what other roles vitamin D plays
in maintaining healthy skin. Skin cells, along with the
cells of our other major organs, have receptor sites for
vitamin D. These sites allow the conversion of vitamin
D (via sun exposure) to its active form. Thus far, the
most substantiated information pertaining to vitamin D
and skin involves its role as a potential treatment for
psoriasis and its involvement in the prevention of skin
cancers.
If you suffer from psoriasis, you should know that the
active form of vitamin D, 1,25-dihydroxyvitamin D3 (also
known as calcitriol) can help control the proliferation
of skin cells that lead to psoriatic lesions and modulate
the immune system's hyper-response to this disorder. Various
topical prescription treatments using vitamin D derivatives
are available, but making sure you consume enough vitamin
D via diet or supplementation plays a role, too. Vitamin
D deficiency, which is actually quite common, can lead
to problems with cell growth and differentiation throughout
the body, including skin. Some researchers are working
to prove that long-term vitamin D deficiency leads to
skin malignancies (skin cancer). The protective effects
of topically-applied vitamin D analogues (chemical compounds
similar to the vitamin D our skin naturally produces in
the presence of sunlight) have been demonstrated in-vivo
(on a live subject), though studies have been conducted
on mouse, rather than human, skin. Understandably, researchers
believe that further exploration into how topically-applied
vitamin D may protect skin cells from the DNA damage that
leads to cancer is worthwhile. In the future, it is possible
that sunscreen recommendations will be accompanied by
new vitamin D dietary guidelines to ensure proper levels
are achieved.
Sources for the above information: The British Journal
of Dermatology, October 2005, pages 706-714; Current Rheumatology
Reports, October 2005, pages 356-364; Photochemistry and
Photobiology, E-Publication, February 1, 2005; The Journal
of Steroid Biochemistry and Molecular Biology, E-Publication,
July 19, 2005 and Experimental Dermatology, December 2004,
page 11).
Paula Begoun
For more detailed information on this topic, see Paula's
article, Vitamin D and Sun Exposure.