The Vitamin D Controversy and the Sun

EMBARGOED UNTIL APRIL 28, 1999

THE VITAMIN D CONTROVERSY AND THE SUN: DISPELLING THE MYTH

NEW YORK (April 28, 1999) - While vitamin D is an essential nutrient in maintaining proper health, there is much dispute as to whether it must be generated through sun exposure and if this process plays a role in warding off internal cancers as touted by recent epidemiological claims.

Speaking today at the American Academy of Dermatology's annual Melanoma/Skin Cancer Detection and Prevention Month press conference, dermatologist Mark Naylor, MD, Assistant Professor, Department of Dermatology, University of Oklahoma, Health Sciences Center, Oklahoma City, OK, discussed the latest studies proving that ultraviolet (UV) exposure is not required for maintaining vitamin D sufficiency nor is UV a scientifically-proven cancer fighter.

Prospective sunscreen trials examining whether sunscreen contributes to vitamin D deficiency found that regular sunscreen users were not vitamin D deficient.

A six-year study of xeroderma pigmentosum patients published in a recent issue of the Journal of the American Academy of Dermatology confirmed these results. These patients, who were highly sun-protected due to a rare skin condition that makes them unable to be exposed to UV without severe skin damage and an increased risk of developing skin cancer, maintained normal vitamin D levels.

"All of these studies suggest that dietary vitamin D is generally sufficient to supply our needs in industrialized countries like Australia and the United States where vitamin D supplementation of foods like bread and dairy products is commonplace," explained Dr. Naylor. "People who practice proper sun protection and are concerned that they are not getting enough vitamin D should either take a multivitamin or drink a few glasses of vitamin D fortified milk every day."

Recent epidemiological studies indirectly linking UV exposure to a decrease in breast, colon and other internal cancers relied principally on geographic location as a basis for conjecture and do not firmly establish a link between sunlight per se and variations in cancer risk. Speculative theories that sun exposure somehow has a beneficial effect on internal cancer risk pose a potential threat to individuals who forgo sun protective behaviors in hopes that sunlight, the principal cause of skin cancer, may lower the risk for other forms of cancer.

Since there is no threshold dose for carcinogens like solar UV, every exposure has some adverse effect - although this may be difficult to measure.

"The best way I can explain the carcinogenic effect of UV exposure is to compare it to smoking cigarettes," said Dr. Naylor. "It may be difficult to measure the harmful effects of smoking a single cigarette or even a pack of cigarettes, but the adverse effect is there nonetheless. The dangers of UV exposure such as chromosome damage, DNA mutation and immune system suppression should be the guiding principle that governs our recommendations to the public, particularly since dietary intake of vitamin D can completely and easily fulfill our needs. If the link is ever firmly established that supplementing vitamin D beyond normal nutritional requirements helps lower the risk of some forms of cancer, we can anticipate that the safest way to administer the vitamin would be through a dietary supplement."

"The Women's Health Initiative, scheduled to reach completion in 2007, is a large scale prospective clinical trial that is attempting to prove the validity of supplementing vitamin D to lower breast and colon cancer risk," added Naylor.

"However, regardless of the outcome of definitive studies on this point, encouraging people to try and boost vitamin D levels by intentionally exposing themselves to carcinogenic ultraviolet is scientifically indefensible in my view."

Skin cancer is rising at an alarming rate, with about 1 million new cases of skin cancer being diagnosed in the United States each year. Approximately 80 percent of these new skin cancer cases will be basal cell carcinoma, 16 percent are squamous cell carcinoma, and 4 percent are melanoma. A report in the April 21, 1999 issue of the Journal of the National Cancer Institute finds that while the number of new cases for most cancers declined from 1990-1996, melanoma is one of the few cancers that continues to rise - at a rate of approximately 3 percent annually. In fact, one person an hour dies from melanoma in this country.

The American Academy of Dermatology, founded in 1938, is the largest, most influential, and most representative of all dermatologic associations. With a membership over 12,000 dermatologists worldwide, the Academy is committed to: advancing the science and art of medicine and surgery related to the skin; advocating high standards in clinical practice, education, and research in dermatology; supporting and enhancing patient care; and promoting a lifetime of healthier skin, hair, and nails. For more information, contact the AAD at 1-888-462-DERM or www.aad.org.

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