Vitamin D 'myths' debunked
Derm: Patients don't need unprotected sun exposure

By Andrew Bowser, Staff Correspondent
Dermatology Times, June 2004

"We know the cause of most skin cancers, and the way to lower the risk of developing them," says Dr. Darrell Rigel, clinical professor, New York University Medical Center, New York. "It's important we try to lower UV exposure, and that should lead to fewer people developing skin cancer."

Unsubstantiated reports extolling the “health benefits” of vitamin D from unprotected sun exposure are confusing the public, Dr. Rigel said at an American Academy of Dermatology (AAD) press conference. His basic message to patients remains the same: Practice proper sun protection to prevent skin cancer.

“When we reject the myths and just look at facts, what we have to do is clear,” Dr. Rigel says. “People are dying from skin cancer. We know how to cut that risk.”

While UV rays from sunlight do trigger vitamin D synthesis in the skin, not much exposure is required to provide "plenty" of this nutrient, Dr. Rigel says. Even individuals who get no UV exposure can ingest vitamin D, in its active form, in vitamin D3-fortified milk, margarine, eggs, chicken livers, salmon and other foods.

Patients concerned about not getting enough vitamin D are likely to have many questions for dermatologists. At the AAD press conference, Dr. Rigel debunked what he described as five common myths promoted in recent reports:

Myth No. 1 - Regular sunscreen use blocks UV exposure, leading to decreased vitamin D levels. In fact, a 1997 study from the Journal of the National Cancer Institute followed a group of xeroderma pigmentosa patients over several years. These patients had normal vitamin D levels despite virtually no UV exposure (Sollitto RB et al., J Am Acad Dermatol. 1997; 37:942-947.).

Myth No. 2 - A significant amount of UV exposure is needed to maintain normal levels of vitamin D. Dr. Rigel says it is easy to maintain normal vitamin D levels with sun exposure incidental to routine daily activities and a normal diet.

Myth No. 3 - Sunscreen blocks all of the UV radiation hitting the skin; therefore, people wearing sunscreen cannot form vitamin D. There is no such thing as a total (or even near-total) UV block. Dr. Rigel says even the most effective sunscreens currently on the market let through enough UV to allow for adequate vitamin D formation.

Myth No. 4 -Skin cancer isn't a really dangerous disease, so protection isn't very important anyway. In fact, one American dies every hour from melanoma.

Myth No. 5 - Decreased vitamin D levels lead to increases in other cancers and other diseases. This claim is based on a study finding that overall cancer rates are higher in the northeast United States. Those making this claim attribute the higher cancer rates in the northeast to the fact that this region has lower sunlight levels than other areas of the country. However, several other studies contradict this, according to Dr. Rigel. One study showed that cancer rates are low in the northern Plains states, which have the lowest UV levels in the country.