June 22, 2010

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By Anne Harding

TUESDAY, June 22, 2010 (Health.com) —  It’s that time of year again. As the weather heats up, people across the country are dusting off their barbecues, breaking out the swimsuits—and working themselves into a frenzy over the latest sunscreen-related health concerns.

Each year since 2007, a consumer watchdog organization known as the Environmental Working Group (EWG) has been issuing a report on sunscreen safety as summer gets under way. The reports tend to be a bit alarming, and this year’s was no different.

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The group gave its stamp of approval to just 39 of the 500 sunscreens it evaluated this year, and it says that some common sunscreen ingredients may disrupt hormone function or even increase the risk of melanoma—the deadliest form of skin cancer.

The hazards outlined in the report have generated headlines and even caught the attention of Charles Schumer, a U.S. Senator for New York. Last week, in response to the report’s mention of a possible link between skin cancer and a type of vitamin A (retinyl palmitate) found in many sunscreens, Sen. Schumer called for the FDA to evaluate the data on the vitamin and map out new sunscreen regulations.

In addition, the EWG stated that sunscreen may be giving sunbathers a “false sense of security” regarding their skin cancer risk, and could even be contributing to vitamin D deficiency.

But don’t cancel that beach vacation just yet. Dermatologists say that while the group does raise some valid concerns, it shouldn’t discourage people from using sunscreen.

Next page: Evidence of harm in humans is lacking

Take retinyl palmitate, for instance, which the EWG identified in 41% of the sunscreens it tested. In one study, lab animals slathered with the substance and exposed to sunlight developed skin tumors faster than animals coated with a placebo cream.

But evidence of harm in humans is lacking. In fact, vitamin A-based drugs are key weapons in the battle against wrinkles (Retin-A), acne (Accutane), and even skin cancer, notes James Spencer, MD, a professor of clinical dermatology at the Mount Sinai School of Medicine, in New York City. He adds that the majority of studies support the safety of vitamin A-based sunscreens. (Dr. Spencer has served as a consultant to Neutrogena and L’Oreal, which make sunscreen in addition to other skin-care products.)

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Vitamin A and its cousins help normalize the growth of sun-damaged skin cells, according to Dr. Spencer, who is also a dermatologist in private practice in St. Petersburg, Fla. “The retinoids have been around for 20 to 30 years,” he says. “They’re remarkably effective medications both systemically and topically.”

Nneka Leiba, MPH, a research analyst at EWG, acknowledges that the risks retinyl palmitate may pose to humans aren’t clear. “Although the evidence is strong, it’s not yet conclusive,” she says. “We want people to be precautious.”

Another chemical cited in the EWG report, oxybenzone, has been a key sunscreen ingredient for decades. Animal research suggests that oxybenzone could disrupt hormonal function, which prompted the EWG to discourage the use of products containing it.

But as with retinyl palmitate, there’s no evidence that the substance hurts humans, says Darrell Rigel, MD, a clinical professor of dermatology at New York University. The chemical’s safety is studied “every weekend in the summer, when tens of millions of Americans are using sunscreen with oxybenzone without any problems,” Dr. Rigel says.

Dermatologists do agree with the EWG that people who use sunscreen—especially products with sky-high sun protection factor (SPF) ratings—shouldn’t feel that they are immune from skin cancer.

Sunscreen alone won’t prevent skin cancer no matter how high the SPF, so people should also use hats, clothing, and shade for sun protection, Leiba says. The American Academy of Dermatology recommends the same two-pronged approach: an SPF 30 sunscreen, combined with protective clothing and shade.

Next page: Too much sunscreen, too little vitamin D?

For most people, using a sunscreen with an SPF above 30 won’t give them much added protection, says Martin Weinstock, MD, a professor of dermatology at Brown Medical School, in Providence.

“It’s sort of diminishing returns as you get to the higher SPF numbers,” says Dr. Weinstock, who chairs the American Cancer Society’s skin cancer advisory committee. “For some people with particular problems very high SPF numbers may be important, but for most people SPF 30 is pretty good.”

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In its report the EWG also noted that people may be risking vitamin D deficiency by using too much sunscreen. “We basically just laid out the different arguments, because it is so controversial,” Leiba explains.

Vitamin D is “a super controversial area,” Dr. Spencer agrees. But, he adds, most people can get all the vitamin D they need by eating a healthy diet and taking supplements. (Vitamin D is added to foods such as milk.) “If you didn’t eat and you never took your vitamin pills, then sun avoidance would be a problem,” he says.

The medical community is itself divided on whether sunlight should be used as a source of vitamin D. While the American Academy of Dermatology advises against unprotected exposure to UV light as a vitamin D source, the American Medical Association recommends that people get a few minutes of unprotected sunlight daily.

Staying safe in the sun isn’t complicated. Both the EWG and dermatologists agree that you should use plenty of sunscreen (SPF 15 to 30 is best), reapply it often, and cover up with hats and protective clothing too.

“We’re not telling people to stay in a cave,” says Dr. Spencer. “We’re just using common protective measures so you can go out and enjoy life.”

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