Next in Skin Cancer Fight: Protection From UVA Rays
We’ve all heard that to protect our skin from the sun’s aging effects and cancer-causing rays, we should stay out of the sun. The next best thing, of course, is to apply sunscreen or wear protective clothing.
One thing that some people don’t realize is that there are two types of ultraviolet radiation that can age your skin and lead to cancer, and the SPF ratings on most sunscreen lotions and sprays address only one: the potent burning rays, or UVB.
The higher the SPF rating on your sunscreen, the more short-wave radiation, or UVB rays, it’s keeping from your skin.
Increasingly, though, dermatologists are concerned about the role of long-wave ultraviolet radiation, the more penetrating rays known as UVA radiation, as another source of burning rays and skin cancer risk. These are the rays that penetrate below the epidermis of the skin, into the dermis, where the body makes collagen and elastin that provide skin’s firmness and structure.
Yet, there is no rating system in place to quantify how well sunscreens shield us specifically from UVA radiation, which is the main type that people are exposed to at tanning salons as well as through sun exposure: solar radiation is about 95% UVA and 5% UVB.
The American Academy of Dermatology has asked the Food and Drug Administration to establish labeling standards for UVA sunscreen ingredients similar to the SPF rating used for UVB.
For now, it’s up to consumers to find products that provide good protection.
Many products that block UVA rays contain physical sunscreens that reflect, scatter or absorb light. They include zinc oxide, the pasty white cream beachgoers smear on their cheeks and noses, and another heavy cream called titanium dioxide.
You might recognize on some labels the term “micronized zinc oxide,” which refers to a lighter version of zinc oxide. There’s also a newer chemical sunscreen, Parsol 1789, that absorbs UVA light.
The jury is out on how well any of these products protect from UVA rays.
Products that claim on their labels to offer “broad spectrum” UVA-UVB protection may not do enough to keep UVA rays from damaging your skin, said Dr. Richard Glogau, a dermatologist at UC San Francisco. “We’ve seen some [products] with SPF 30 and SPF 45 that have poor and mediocre UVA protection.”
Dr. Arnold Klein, a Beverly Hills dermatologist, also notes that there haven’t been scientific studies to show that micronized zinc or titanium dioxide are good blockers of UVA radiation.
Klein prefers mexoryl, a product derived from camphor that’s available for use in sunscreens in Europe but not yet in this country. It’s been shown in several European studies to offer superior protection against a broad range of UVA radiation. This product is available in the Anthelios sunscreen line made by France’s La Roche-Posay. The FDA is reviewing mexoryl for sunscreen use, but for now you can buy Anthelios products in Canada or France, or from foreign-based Internet sites.
Dermatologists say people are much too sparing with sunscreens. They recommend that people apply sunscreens with a rating of at least SPF 15 as part of their daily ritual, before going to school or work, and before outdoor activities. When outdoors, sunscreens should be reapplied after 30 minutes in the sun and every couple of hours after that, more if they rub off or after swimming.
Meantime, researchers are working on a sunscreen pill that could make full-body sun protection even better.
