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Lawmakers around the country are turning up the heat on the tanning bed industry, blaming the popularity of indoor tanning among young people for rising skin cancer rates. As this ScienCentral News video explains, new scientific research on the benefits of vitamin D has clouded the debate.
Sun Screen
With fall around the corner, Americans will need to find other ways to get tan. With indoor tanning parlors, the weather outside is irrelevant. But dermatologists have warned there's too much tanning going on, indoors and out.
"We know the cause of skin cancer — too much ultraviolet light," says James Spencer, vice-chair and director of dermatologic surgery at Mount Sinai School of Medicine. "We could prevent that, and yet, the incidence of skin cancer is rising, letting us know that we're still getting too much ultraviolet light."
Indoor tanning is especially popular among teenage girls, which worries dermatologists like Spencer. "When you look at the population and who's going to indoor tanning, it's young people, teenagers, most often young women," he says. "And this is the peak of their sensitivity, this is the time when they should be avoiding this the most."
A study at Case Western Reserve University looked at the tanning behavior of white American teens, using data from the National Longitudinal Study of Adolescent Health ("Add Health") confirmed those concerns. "Fully 24 percent of the teens in our study...used an indoor tanning facility at least once," says Catherine Demko of the Comprehensive Cancer Center at Case Western Reserve University School of Medicine and University Hospitals of Cleveland. "Females were far more likely to use it than males, and by the time girls were 18 or 19 years old, about 47 percent reported that they had used an indoor tanning facility three or more times." The study, published in the journal of Archives of Pediatrics and Adolescent Medicine, suggests that teenagers don't see tanning as potentially dangerous behavior.
The Indoor Tanning Association believes that "humans need ultraviolet light to survive" and that "the risks associated with ultraviolet light from the sun and from indoor tanning units are easily managed when consumers avoid sunburn."
"I am not satisfied with the message that burning is bad, but tanning is good," says Kevin Cooper, professor and chair of the department of dermatology at Case Western Reserve University. "There's no way you can get a tan without damaging the skin. That's what the tan is." Cooper says the message should be "that whatever color you are is OK, that's it's not necessary for you to be dark in order to be accepted."
Spencer points to studies of mice, which get a type of skin cancer humans get. "Half of [the mice] got a big blast of UV light that caused a sunburn," explains Spencer. "The other half got the same dose, but divided up into many little small packets, a little bit each day for many many weeks, such as a tanner might get." Which half got more skin cancer? "The answer was the tanners. The little bit each day is actually more carcinogenic than the big blast that caused the sunburn."
But some researchers think if we avoid the sun, we are preventing our bodies from getting vitamin D, which our skin needs sunlight to produce. "Vitamin D has always been recognized as being very important for child bone health, and vitamin D deficiency of course causes rickets in children," says Michael Holick, professor of dermatology, medicine physiology and biophysics at Boston University Medical Center. "But we also know that vitamin D is really clinically important throughout our entire lives, not only for bone health, but for a wide variety of physiological processes."
Vitamin D together with calcium is known to protect against bone diseases including osteoporosis and osteomalacia in adults. And a growing body of evidence shows that vitamin D may also protect against diseases such as multiple sclerosis, hypertension, depression, and colon, breast and prostate cancers. A 2002 study in the journal Cancer estimates that tens of thousands of Americans die each year from cancers possibly caused by too little sun exposure and too little vitamin D.
At the same time, there is evidence indicating low circulating levels of vitamin D in the U.S. and the re-emergence of rickets caused by vitamin D deficiency. In October 2003, the National Institutes of Health responded to these new findings by holding its first ever conference on the problem, "Vitamin D and Health in the 21st Century."
The Institute of Medicine has set 200 international units of vitamin D as the adequate allowance for adults under fifty — that's two glasses of milk a day. But research by Holick and others suggests we need five times that amount. "We think that you need 1000 international units of vitamin D a day," says Holick. "There's about 100 international units of Vitamin D in 8 ounces of milk, orange juice is now fortified with Vitamin D, 100 units per 8 ounces orange juice. So even if you drank one or two glasses of milk a day and one or two glasses of orange juice each day, you're getting no more than 20 to 40 percent of the vitamin D requirement that truly satisfies your body's needs."
Holick and others say the best way to get that amount is moderate exposure to sunlight — "typically for a white person say in New York or in Boston that would be no more than probably 5 to 10 minutes on your arms and legs, or your face, hands and arms, two to three times a week," he says. "I then recommend that you put sunscreen on with a sun protection factor of at least 15." He believes that dermatologists have been "so brainwashed, for now up to two decades, that any sun exposure markedly increases your risk for skin cancer, that they've not been willing to look at the newest information."
In his book, The UV Advantage, Holick emphasizes he is not an advocate of indoor tanning. But the tanning industry has embraced his message. "Dr Holick's book is probably one of the best things that's happened to our industry," says Dan Humiston, president of the Indoor Tanning Association and owner of a chain of tanning salons. "Whether it's the tanning industry or it's people that go to the beach, this is welcome news."
Not to the American Academy of Dermatology, which issued a statement saying that "reports linking the health benefits of Vitamin D to unprotected sun exposure mislead the public."
"You do not need to go to the beach or the tanning parlor to raise your vitamin D — and get wrinkles and skin cancer — when you can just simply eat a balanced diet and take vitamin supplements if you want," says Spencer. "We don't really know that vitamin D prevents cancer. To say that vitamin D prevents cancer is a wild speculation. To say that ultraviolet light causes skin cancer is a fact."
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