Could a Common Sunscreen Ingredient Speed Cancer Development?
I could really use some better sunscreen. Red-headed, freckled, and ridiculously pale (think: a few shades lighter than your average slice of Wonder Bread), I burn at the slightest suggestion of a sunny day, even though I religiously slather on the SPF one-bazillion goop. Last year, I wrote a piece for Mother Jones about how sunscreen manufacturers' claims (All day protection! Sweat proof! SPF through the roof!) rarely measure up to the products' performance. So when I heard that the Environmental Working Group was releasing its 2010 list of best and worst sunscreens, I had hope: Would this be the year sunscreen manufacturers finally figured out how to save me from turning into a Twizzler after 10 minutes of yard work?
You'd think so, since according to the new report, 1 in 6 sunscreens is now labeled with an SPF of above 50, compared to 1 in 8 last year. Sounds like good news, since higher SPF means more protection, right? Not really, says EWG senior analyst Sean Gray. The difference between an SPF 50 product and and SPF 110 product is minuscule. Gray believes the sky-high SPF labels can actually be dangerous. "We have studies that show that people who use the higher SPF products don't reapply it," says Gray. "So they end up with more UV exposure overall." (Mother Jones reported on this phenomenon back in the day.)
Another scary new finding: There is preliminary evidence from a recent FDA animal study that a form of vitamin A called retinyl palmitate, present in about 40 percent of sunscreens, may accelerate the development of skin cancer. Researchers applied sunscreens containing retinyl palmitate to one group of hairless mice and sunscreens without the additive to another group. When exposed to UV radiation, the retinyl palmitate group developed lesions and tumors significantly faster than than the non-retinyl palmitate group. What's frightening is that people see "vitamin" and "think it's good for them," says Gray.
So which sunscreens are best? EWG says so-called "mineral blockers," which generally use nanoparticles of zinc or titanium oxide to block UV light, are safer than "chemical blockers," since they protect against both UVA and UVB rays (UVB cause burns, but UVA rays have been linked to skin cancer) and don't become unstable in sunlight. Are nanoparticles completely safe? "All the research we’ve looked at suggests they don't penetrate the skin, but there is still debate about that," says Gray. If you do choose a chemical blocker, choose one with avobenzone, which protects against both UVA and UVB rays. Stay away from oxybenzone, which only filters out UVB light, and could also disrupt hormonal function.
The bright side: The FDA expects to debut its long-awaited new sunscreen labeling system—which will require manufacturers to include information about both UVA and UVB protection and ban claims of SPFs higher than 50—this coming October.
Here's a list of EWG's best and worst sunscreens of 2010: