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The Sun And Vitamin D: A Great Debate

Exposing Arms, Legs For 10 Minutes Several Times A Week In Summer Can Store Up Vital Hormone,1,7578420.story?coll=hc-headlines-health

June 9, 2004
Garrett Condon
The Hartford Courant

Dermatologists have spent decades telling us that beach blanket bingo -unprotected fun in the sun - is really Russian roulette. Catching the sun's hottest rays over time increases the chances that you'll catch something else: skin cancer. But is Mr. Sunshine all bad?

As the warm weather rolls in, Dr. Michael Holick, a maverick Boston University researcher, is challenging long-established sun-safety guidelines in a new book, "The UV Advantage."

In Holick's view - and he is not alone - many Americans in northern climes are deficient in vitamin D, a hormone that has several health benefits, including helping the body use calcium to build strong bones.

He says the best way to get some D is to get some sun.

This unorthodox advice - and Holick's ties to the indoor-tanning industry - have been hotly denounced by many mainstream dermatologists who stress that the traditional guidelines are based on the best science and remain unchanged.

Low levels of vitamin D are known to cause rickets in children and osteomalacia in adults, which results in weak muscles and bones. Holick, a professor of medicine, physiology and biophysics at BU School of Medicine, is well-known in scientific circles for his research into vitamin D. His work led, among other things, to the use of activated vitamin D in the treatment of psoriasis.

Holick contends that vitamin D deficiency also may play a role in the development of various cancers, as well as Type 1 diabetes, multiple sclerosis, rheumatoid arthritis and other illnesses.

Dietary guidelines for Americans call for the daily intake of 200 to 600 international units (IU) of vitamin D, with oldsters needing to get the most. Holick, who was on the panel that helped create the guidelines in 1997, says that subsequent research has shown that individuals really need 1,000 IUs a day, which would be difficult to get solely from food. (A quart of milk has 400 IUs of vitamin D.)

His recommendation: brief, "safe" periods of sun exposure based on skin type, latitude and time of year as spelled out in his book.

For example, Holick would encourage a fair-skinned person living in Connecticut to expose his or her arms and legs or hands, arms and face for five to 10 minutes at midday in the summer twice or three times a week. (Those with sun-damaged facial skin should avoid exposing the face, he says.) Such a practice would provide an individual with enough vitamin D for the year, even without vitamin D in the diet, he says.

After the unprotected exposure, he recommends all of the usual sun protection measures, including shade, protective clothing and sunscreen.

"Does that sound outrageous, radical?" he says. Dermatologists who have criticized him don't think people are sophisticated enough to know the difference between a brief, timed exposure and spending the day baking on the beach, he says.

But critics say this isn't just a quibble over five minutes in the sun.

Dr. Darrell Rigel is a clinical professor of dermatology at New York University School of Medicine who researches melanoma, the most deadly form of skin cancer. Rigel says the idea that individuals need much more vitamin D and that there is a health-threatening epidemic of vitamin D deficiency is "not even science, it's hypothesis." What is known, he says, is that, on average, one American dies every hour from skin cancer - mainly from melanoma.

Individuals don't need to be told to sit out in the sun, Rigel says. "You get exposed walking on the street, walking to your car. Why intentionally expose yourself? When the public gets this information, they get confused, and that's the worst thing that can happen."

He says the increase in skin-cancer cases for people younger than 40 has begun to level off - an encouraging development that he attributes in part to the sun-safety message sinking in.

Critics also focus on Holick's ties to the tanning industry. He admits that he has taken unrestricted grants from the Indoor Tanning Association, which represents the nation's 25,000 tanning parlors, although he says tanning-industry money represents only a small fraction of his funds.

In his book, he writes that he is "not an advocate of tanning per se," but provides a detailed guide to using tanning facilities to educate the 26 million Americans who will use them each year. He has spoken at tanning-industry gatherings.

Holick encourages readers to use his brief-exposure guidelines for indoor tanning. But Jeff Nedelman, a spokesman for the ITA in Vienna, Va., acknowledges that most people who use tanning beds are fair-skinned and probably get more ultraviolet light than Holick recommends.

Dr. Jane Grant-Kels, professor and chairwoman of dermatology at the University of Connecticut Health Center, says that tanning beds add to an individual's cumulative over-exposure to ultraviolet light, which is what causes cancer. She finds Holick's ties to the tanning industry unsettling.

But for one of Grant-Kels' colleagues, the part of Holick's message about vitamin D deficiency stands up to scrutiny. Dr. Jo-Anne Smith, associate director of the Center for Osteoporosis at the UConn Health Center, says that many in her field now believe that a significant number of Americans - especially those in New England and other northern latitudes - need more vitamin D. Studies suggest that seniors who lack vitamin D are more likely to suffer falls and fractures. However, Smith says, she would much rather see the problem attacked with heavy-duty dietary supplements, not more time in the sun.

"I don't think we should have to be at odds with the dermatologists," she says.

Copyright © 2004, The Hartford Courant