But the evidence is inconclusive as to whether sunscreens reduce the risk of basal cell cancer and melanoma, the most deadly form of skin cancer. Some scientists have accused dermatologists and the sunscreen industry with scaring Americans out of the sun's powerful ultraviolet (UV) rays, which the body needs to generate vitamin D.
Still, as a fair-skinned, light-haired sun worshiper who has every other risk factor for skin cancer, I consider sunscreen an important tool. Here's how to use it wisely.
Seek shade or make it. Don't use sunscreens as a first line of defense against melanoma or a license to bask in the sun, said Robert J. Davis, author of "The Healthy Skeptic" (University of California Press, $21.95). Instead, stay out of the sun at peak hours - 10 a.m. to 4 p.m. - and "cover up with dark-colored clothing that's made of tightly woven fabric or specially treated to block UV radiation," Davis wrote.
The oxybenzone debate. The EWG recommends avoiding sunscreens containing the commonly used chemical oxybenzone out of concern that it can disrupt hormones, cause allergic reactions and damage cells. "It's one of the most absorbed sunscreen blockers, which wouldn't necessarily be a concern but it has high toxicity issues," said EWG senior analyst Sonya Lunder. But the American Academy of Dermatology (AAD) recommends oxybenzone because it ensures "broad-spectrum" coverage, which means it filters out both UVA and UVB light. Pick your side.
Be wary of "seals of approval." The AAD has been criticized by some of its members for its commercial endorsement of sunscreens. Many AAD officers have ties to companies that manufacture sunscreens. One product with the AAD seal, Johnson & Johnson's Aveeno Sunblock Lotion with SPF 55, contains oxybenzone; it scored a "moderate" risk in the EWG rankings.
The Skin Cancer Foundation also has a "seal of recommendation" program. But "the main criterion for displaying the seal is donating $10,000 to SCF to join the Corporate Council," Davis wrote.
For a fee, sunscreen manufacturers such as Neutrogena display the American Cancer Society logo on their products. Only one Neutrogena product - the mineral-based Neutrogena Sensitive Skin Sunblock Lotion, SPF 30 - is recommended by EWG.
The Sun Safety Alliance, which promotes sunscreen use, was founded by the National Association of Chain Drug Stores, whose members sell sunscreens, and Schering-Plough, maker of Coppertone, according to Davis.
Don't rely on SPFs. The Sun Protection Factor numbers (SPFs) refer only to the ability to deflect UVB rays. Look for "broad spectrum" to protect against both UVA and UVB rays. An SPF 30 screens 97 percent of UVB rays; an SPF 15 screens 93 percent of UVB rays. Rather than reach for SPF 70, apply a lower number generously and often.
Use at least 7 percent zinc oxide or titanium dioxide. Zinc and titanium act as a physical barrier on the skin and, unlike other sunscreen chemicals, don't penetrate the skin, don't show hormone-like activity, don't break down in the sun and block a wider spectrum of the sun's rays than other products.
May is Melanoma/Skin Cancer Detection and Prevention Month. For more information about skin cancer and melanoma, contact the American Academy of Dermatology.
(c) Chicago Tribune.