Health & Fitness

The new science of sun protection

Mehmet Oz, M.D., and Michael Roizen, M.D.
Mehmet Oz, M.D., and Michael Roizen, M.D.

Got a love-hate relationship with your sunscreen? You’re not alone. We plunk down nearly $400 million a year on sun-care products in bottles, cans, tubes and sticks — even as new research shows that many don’t live up to the protection promise on the label, contain troubling chemicals and are prone to user errors, like not reapplying at specified intervals or after that dunk in the pool.

But hold it. We still think the right sunscreen, worn the right way, is important for reducing your exposure to the sun’s skin-frying ultraviolet rays that cause wrinkling, age spots and up to 90 percent of all skin cancers. Just don’t make that sticky bottle in your beach bag your only protection strategy.

Here’s our latest guide to the new science of sun protection:

No. 1: Skip sunscreens that let you down. Plenty of sun-care products filter only the sun’s UVB rays, the kind that trigger nasty sunburns. They let UVA through. That’s dangerous, because UVA rays ding DNA in skin cells in two ways that promote the development of melanoma, the deadliest skin cancer. First, UVA penetrates deeper into the skin, causing damage that can transform healthy, young skin cells into cancer cells. Second, it also switches off a gene that guards against this transformation.

Good to know: A product’s SPF (sun protection factor) refers only to how well it blocks UVB. You need that (we like an SPF of 30), but don’t stop there. Make sure your sunscreen also says “broad spectrum” on the label. This means it contains ingredients that filter or reflect UVA.

No. 2: Steer clear of questionable chemicals. Lots of sunscreens contain UV-shielding ingredients that may act like hormones in the body or could trigger allergies and asthma attacks, according to research by the Environmental Working Group and the Silent Spring Institute. These include oxybenzone, found in most chemical sunscreens. Lab research suggests that it may affect the development of a fetus. Some also contain methylisothiazolinone, a preservative that may trigger skin allergies, and retinyl palmitate, a skin-conditioning agent that in lab studies spurred the growth of cancer cells in the presence of sunlight.

Good to know: We advocate using mineral-based sunscreens containing zinc oxide or titanium dioxide, which act as physical sun blockers, reflecting UV rays away from your skin. But a new analysis by Consumer Reports has found that just one in four mineral sunscreens actually protected at the SPF level on the label. Skip to No. 4 for our take on what to do about that.

No. 3: Stop skimping! Sunscreen’s not magic, but plenty of people think one application is all you need. In one study, people wearing higher SPF types stayed out in the sun longer and were more likely to get sunburned than those who wore lower SPF sunscreens. Other mistakes that mess up your protection include not using enough, not reapplying often enough and only slathering up when you know you’ll be outdoors for a while.

Good to know: Use an ounce (about a shotglass full) every time you put on sunscreen; reapply after swimming, sweating or every three to four hours. And don’t be fooled by higher SPF numbers; compared to SPF 30, an SPF 50 product only protects against an extra 1 percent of UVB rays. Use sunscreen on cloudy days and even if you have darker skin. It’s also wise to pat a daily sunscreen on your face and other exposed skin, as small, daily doses of sun protection contribute to protecting skin from cancer, too.

No. 4: Cover up and sit in the shade. Don’t rely on sunscreen alone. It’s difficult to remember to put it on every day, and using it less often isn’t proven to protect much against skin cancer. Invest in a hat with a wide brim, sunglasses with big lenses and a shirt and pants with a UPF (ultraviolet protection factor) of at least 30, too. That way you can enjoy the summer sun without getting fried.

Mehmet Oz, M.D. is host of “The Dr. Oz Show,” and Mike Roizen, M.D. is Chief Wellness Officer and Chair of Wellness Institute at Cleveland Clinic. To live your healthiest, tune into “The Dr. Oz Show” or visit www.sharecare.com.

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