Sunshine vitamin stirs new debate

Remember all the advice we’ve heard about skin cancer — stay out of the sun, cover up, wear sunblock?

Now some doctors are saying that it has resulted in a new health problem - millions of people worldwide are suffering from vitamin D deficiency. And the scientific and therapeutic disagreements between dermatologists and nutritionists are heating up.

Dr. Michael Holick, a Boston University professor of medicine and physiology and author of a forthcoming book “The Vitamin D Solution,” has called the deficiency “probably the most common nutritional and medical condition in the world,” affecting “more than 50 percent of the world’s population.”

Seventy-seven percent of Americans have insufficient amounts of vitamin D, according to a November article from Consumer Reports on Health, which cited a study published in the Archives of Internal Medicine that was based on government figures. Late last month, the journal Pediatrics published the first assessment of vitamin D levels in U.S. children ages 1 to 11, which said at least one-fifth don’t get enough vitamin D.

As research papers on the subject keep proliferating, more primary care doctors are recommending that patients take increased vitamin D doses through over-the-counter supplements.

The vitamin is actually an inert hormone produced photochemically in the skin of humans and most animals, a process stimulated by sunlight - and that’s where some of the rub is. Dermatologists have long maintained that exposure to the sun at peak hours without sunblock raises the risk of skin cancer, including deadly forms of melanoma.

“Dermatologists have gone way overboard in telling people to stay out of the sun,” Dr. Andrew Weil, a best-selling author, said in an interview. “A more useful view is that solar radiation can both increase and decrease cancer through a complex environmental interaction involving many variables, including differences in genes, biochemistry and lifestyle.”

Dr. Holick said his advice was to “be sensible,” though he lost his job as professor of dermatology at Boston University School of Medicine in 2004 as a result of his belief in the benefits of sunshine. “Fortunately, I had other appointments” elsewhere at the medical school, he said.

Dr. Marvin Lipman, chief medical adviser for Consumers Union, said he has no qualms about getting vitamin D by exposing his face and arms to the sun for 15 or 20 minutes midday with minimal or no sunblock. He had found his own levels low and, even though he is a “nonbeliever in supplements per se,” he recognizes that the vitamin “is one we don’t get enough of from food.”

Nor was he hesitant when, in talking about the differing views among professionals, he said in a half-joking way: “You can see a turf war coming up.”

But dermatologists say, vitamin D deficiency or not, that the cancer risks of sun exposure are certain and there’s no way to make a medical recommendation on “safe sun.”

“We know there is a known carcinogen in ultraviolet rays. So to say ‘five minutes or such is safe’ - safer than what?” asked Dr. Sandra Read, a Washington dermatologist. “We are all so different in our skin types and composition, it would be hard to tailor a message that is safe.”

“What I tell my patients is that if you are deemed to be low [in vitamin D] by your doctor, you can do it safely by supplements and nutrients,” Dr. Read said.

Dr. Elizabeth Tanzi, a D.C. laser and cosmetic dermatologist who has a vitamin D deficiency herself, agreed that there are better and safer sources than the sun.

“What matters is where you are getting it,” she said. “You may be trading off something healthy with something that is a known risk. It is a slippery slope, a question of amounts, because no one can say exactly how much one needs.”

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