Can Sunscreen Cause Cancer?

by Caitlin Boyle

3 common sunscreen myths -- exposed

It's hard to put sunscreen on a baby. They wiggle and twist, and sunscreen ends up on their clothes and in their hair. It's such a mess that I'm sure many parents think, "Oh, never mind! One time without sunscreen can't be that bad."

But it really can be that bad. The Center for Disease Control states that adults who experienced at least one blistering sunburn during childhood are two times more likely to develop melanoma. My son is fair-skinned, so I am especially concerned about reducing his risk of skin cancer. Whenever we go to the park, I high-tail it to the swings and plop him in the toddler seat. Once he's trapped and distracted, I begin to sunscreen him up. Works like a charm!

It's not just children that need sunscreen, of course. UV ray exposure increases the odds that adults will develop skin cancer, too. And yet many of us don't regularly wear sun protection. We don't want to be inconvenienced, we don't like the feel of it, or we just plain forget. Or we've heard rumors that sunscreen can actually cause cancer.

Experts recommend that we minimize the time we spend outdoors, wear protective clothing and a hat, and stay in the shade as much as possible. But that's not enough. You have to wear sunscreen, too.

Not convinced? I admit, I was skeptical, too. So I talked to some top docs to find out what they had to say about some common beliefs surrounding sunscreen.

But I've heard sunscreen increases the risk of melanoma!

According to Dr. Warwick Morison and Dr. Steve Wang, dermatologists and members of The Skin Cancer Foundation's Photobiology Committee, a "comprehensive review of all studies from 1966 to 2003 found no evidence that sunscreen increases melanoma risk." Morison and Wang point to a large study of over 1,600 Australians that found that regular sunscreen users reduced their incidence of melanoma -- the most dangerous type of skin cancer -- by 50 to 73 percent.

The reason that many regular sunscreen users develop skin cancer is because they feel so protected by the sunscreen that they stay out in the sun even longer, absorbing excess radiation. All sunscreens must be reapplied after two hours (and after every dip in the pool!) to be effective. And remember, even the most effective sunscreens don't offer 100 percent protection from all rays. That's why hats and other protective clothing are also recommended.

But what about vitamin D deficiency? Doesn't sunscreen cause that?

The Skin Cancer Foundation believes that such claims are unproven, and a review of over 1,000 studies by the Institute of Medicine found that most Americans not only ingest or absorb enough vitamin D, but there's no strong link between vitamin D deficiency and diseases like cancer. "The health risks of UV exposure -- including skin cancer and premature skin aging -- are great, and except for bone loss, far better proven than the suggested dangers of vitamin D insufficiency," note Morison and Wang.

It's worth noting that the CDC determined that 3.2% of white Americans, 12% of Mexican Americans, and 31% of Hispanic Americans have a vitamin D deficiency. Adults need 600 -- 800 IUs of vitamin D a day, depending on their age. Foods like salmon, tuna and fortified milk and breakfast cereal are sources of vitamin D, but most Americans will get at least some of their vitamin D needs from the sun. This isn't an invitation to lay outside in the sunshine, however. The CDC says that it's "prudent" to balance the importance of sunlight for vitamin D with the risk for skin cancer. A few short minutes of sun sans sunscreen each day is probably enough.

Should I avoid ingredients like vitamin A and oxybenzone?

There is an often-cited Food and Drug Administration study that concluded that vitamin A (retinyl palmitate), when applied to laboratory animals, increased the instance of skin cancer when the animals were exposed to UV light. However, it's worth noting that this study is still waiting for peer review, and there have been no studies on human subjects that draw a link between vitamin A and increased cancer use, according to The Skin Cancer Foundation.

Some researchers are also concerned about the ingredient oxybenzone, which they identify as a potential hormone disruptor. The chemical, which can protect your skin against both UVA and UVB rays, has mimicked estrogen in lab mice. The Skin Cancer Foundation points out that the levels given to the lab mice were exceedingly high, much more than present in sunscreen. Additionally, oxybenzone does not accumulate in the human body -- it is simply excreted. "The ingredient is FDA-approved for human use based on exhaustive review," say Morison and Wang.

So what sunscreen should I buy?

Bottom line: Any sunscreen is better than no sunscreen. Protection from sun damage and skin cancer begins with healthy sun habits, like avoiding going outside when the sun is the strongest (from 10 AM to 2 PM), wearing a long-sleeve shirt and pants, wearing a hat and staying in the shade. Put on sunscreen every day and reapply as necessary. Use an ounce -- roughly a handful -- of sunscreen on your entire body. Most people don't put on enough sunscreen.

If you are concerned about the chemicals in sunscreen, look for products that contain a physical/mineral blocker like zinc oxide or titanium dioxide. Unlike chemical-based sunscreens, which have to absorb into the skin to work, these sunscreens work immediately and effectively block both UVA and UVB rays.

Try these mineral-based sunscreens for both adults and child age six months and older: