By Karen Ravn, Special to the Los Angeles Times
June 30, 2012
It's a conundrum. You want to have fun in the sun, but you don't want skin cancer or — heaven forbid! — wrinkles. Maybe you think you have it made in the shade with sunscreen. But while most sun and skin experts would advise you to slather the stuff on like crazy, many also would warn you not to rely on it too, too much.
In May, the Environmental Working Group, or EWG, a nonprofit organization in Washington, D.C., concerned with health and the environment, released its annual Sunscreen Safety Guide. It comes down in favor of using sunscreens, but it also raises concerns, which, in turn have raised some controversy.
"It's frustrating," says Dr. Darrell Rigel, a professor of dermatology at New York University, who believes the EWG may weigh environmental concerns too heavily in its work. "People don't wear sunscreen because it's environmentally friendly. They wear it to protect themselves from cancer. ... The danger is that people will be confused and not use any."
A look at some of the EWG claims may shed a little light.
EWG claim: "There's no consensus that sunscreens prevent skin cancer."
The EWG says regular sunscreen use has been shown to reduce risk for squamous cell cancer (treatable; comprises 16% of skin cancers) but not necessarily for basal cell cancer (treatable; 80%) or melanoma (potentially deadly; 4%). Also, while new federal rules slated to take effect in December allow sunscreen makers to claim that their products lower the risk of skin cancer, they will not allow makers to claim their products do so alone — that is, without other protective measures.
"The data are conflicting," says Dr. Sumaira Aasi, associate professor and director of dermatologic surgery at Stanford University. But, she contends, definitive proof that sunscreens prevent skin cancer would require one group of people to use sunscreen — regularly, properly — and another group not to use any, with the two groups spending the same amount of time exposed to the same amount of UV radiation over their lives. In other words, impossible to come by.
Still, Aasi is satisfied that evidence shows a correlation, at least, between sunscreen use and reduced cancer risk. "Sunscreens are a part of the story. They're not everything, but a part."
EWG claim: "There's some evidence that sunscreens might increase the risk of the deadliest form of skin cancer for some people."
The deadliest form of skin cancer is melanoma, and the EWG cites studies showing an increased risk of it among sunscreen users. They offer three possible explanations for this surprising result: (1) Sunscreen users stay out in the sun longer and end up exposed to more UV radiation than non-users. "I think this is because when using sunscreen, people change their behaviors and feel much more invincible," says David Andrews, a senior scientist at EWG. (2) Some sunscreen chemicals break down in sunlight and release free radicals, which are unstable molecules thought to be involved in the development of cancer. (Antioxidants are supposed to be good for us because they can neutralize free radicals.) (3) Protection against UVA rays may be what counts with melanoma, and historically many sunscreens have offered little or no protection against UVA rays.
The EWG also notes that some studies have shown decreased risk of melanoma among sunscreen users, including a 2011 Australian study that, after 10 years, found half as many new melanomas among daily sunscreen users as among those who used it at their own discretion.
Many dermatologists seem more convinced by the 2011 Australian study than the EWG does, and they consider studies showing an increased risk of melanoma among sunscreen users to be misleading. Aasi agrees with Andrews: "Sunscreen users get a false sense of security."
EWG claim: "There are dozens of high-SPF products but no proof they're better."
TheU.S. Food and Drug Administrationhas called SPF values higher than 50 "misleading to the consumer," the EWG reports, and has seen no evidence that users get any added benefit as the values keep going up. The EWG also cites fears that the higher the SPF, the more tempted users will be to stay too long in the sun.
Aasi agrees that a cap on SPF ratings would be helpful for consumers. In fact, she sees no greatly added benefit for SPF values of more than 30. "It's better to reapply every couple of hours," she says.
EWG claim: Pick your sunscreen: nanomaterials or potential hormone disrupters.
The EWG picks nanomaterials.
There are two main types of sunscreens: physical (mineral or inorganic) and chemical (organic). Physical screens (zinc oxide and titanium dioxide) work by deflecting UV rays, while chemical screens work by absorbing them (instead of your skin doing so). The trouble with physical screens, as Aasi says, is mostly that "people don't like the look." Sunscreen makers have solved that problem by using micronized versions of the minerals — "Very few are really nanoparticles," Rigel says — and the EWG says there's no evidence that the minerals, even in miniature form, can penetrate the skin and do any damage. Among chemical sunscreens, the group recommends using those that contain 3% avobenzone (for UVA protection) and avoiding "the notorious hormone disrupter oxybenzone."
Dermatologists are not generally convinced that oxybenzone deserves that bad rap. Evidence of its disruptive nature has only come with lab animals. "And in order to achieve the levels used in the animals, you'd have to apply sunscreen to your whole body for 100 years," says Dr. Henry Lim, chairman of the department of dermatology at Henry Ford Hospital in Detroit and spokesman for the American Academy of Dermatology.
EWG recommendation: Use sunscreens, "just not as your first line of defense against the sun."
"Findings really argue that sunscreen usage is only part of a balanced sun protection that includes covering up and seeking shade," EWG senior scientist Andrews says.
That's something all the experts seem to agree on.
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