By Bonnie Jenkins

Summer is officially here—and for many that means spending more time under the blazing sun. But even doing a bit of gardening or driving around town sans sunscreen can leave you vulnerable to skin damage. Enough cummulative damage can eventually lead to skin cancer—a potentially deadly disease that affects one in every five Americans.

But you can prevent skin cancer from developing in the first place by practicing a little proactive protection. Most dermatologists recommend a generous slathering—one full ounce or more—of sunscreen before exposing yourself to the sun’s rays. Sounds reasonable, right? The problem is, many of the sunscreens you’ll find in drugstores and even health food stores don’t offer full-spectrum protection. Worse yet, they may contain chemicals that can cause free radical damage or disrupt your hormones. How prevalent is the problem? In an analysis of 1,796 name-brand sunscreens on the market in summer 2009, the Environmental Working Group found that two out of five sunscreens offer inadequate protection from the sun, or contain ingredients with significant safety concerns.

Many commonly used sunscreen chemicals have strong estrogenic actions that may cause serious problems in sexual development and adult sexual function. Over time, exposure to endocrine disrupting chemicals can also increase the risk of hormone driven cancers like breast, ovarian or prostate cancer.

One popular sunscreen ingredient, a chemical listed on labels as either oxybenzone or benozophenone-3, effectively protects against both UVA and UVB rays. But, according to several recent studies, this chemical also mimics the effects of estrogen. The U.S. Centers for Disease Control and Prevention (CDC) has found detectable levels of oxybenzone in the urine of 97 percent of Americans over the age of six. In laboratory tests, oxybenzone been shown to disrupt the endocrine system and release reactive oxygen species that could contribute to skin cancer. Up to nine percent of oxybenzone applied to the skin absorbs into living tissues and blood vessels below the surface. While that might not sound like much, it’s important to know that oxybenzone and other hormone disrupting chemicals build up in the body. This means that continually adding small amounts eventually translates to a substantial body burden.

Oxybenzone isn’t the only estrogen mimic in sunscreens. A well-known study by Margaret Schlumpf and her colleagues at the University of Zurich, Switzerland found that many widely-used sunscreen chemicals are estrogenic.  Her group tested six common chemicals that are used in sunscreens. Five of the six tested chemicals (oxybenzone, homosalate, 4-methyl-benzylidene camphor (4-MBC), octyl-methoxycinnamate and octyl-dimethyl-PABA) behaved like strong estrogens in lab tests and caused cancer cells to grow more rapidly.

Studies show that many heavily-used chemical sunscreens may also increase cancer risk by generating free radicals. One small but impossible-to-ignore study published in Free Radical Biology & Medicine suggests that certain sunscreen ingredients may cause more free radicals to form than if you used no sunscreen at all. The study, which was conducted at the University of California, Riverside, points to three commonly used, FDA-approved sunscreen filters—octyl methoxycinnamate, octocrylene, and oxybenzone. These chemicals can boost the number of free radicals over time as they break down and are absorbed into the skin.

According to the study findings, one hour after a ten-minute session of UV exposure, oxybenzone elevated free radicals by 64 percent compared to the control, while octyl methoxycinnamate and octocrylene boosted free radicals by 33 percent and 16 percent, respectively. Ironically enough, failure to reapply the sunscreen frequently seems to compound the damage to skin. According to the study’s lead author, “Not reapplying every two hours would mean that you would have minimal sun protection, and the sunscreen itself could generate free radicals.”

Fortunately, Mother Nature has supplied effective and safe UV screening agents. Zinc oxide and titanium dioxide are natural minerals that create a physical barrier on the skin. Unlike sunscreens, which absorb ultraviolet light, these sunblocks scatter UV rays away from the skin’s surface. Often paired with botanical sunscreens such as green tea, grape seed proanthocyanidins and resveratrol, these minerals safely protect against both UVA (the rays that suppress the immune system and promote melanoma, the deadliest form of skin cancer) and UVB (the rays leading to the less serious squamous and basal-cell skin cancers).

Antioxidants also can play a role in protecting skin from UV damage. According to a study published in the Journal of the American Academy of Dermatology, vitamins C and E not only protect against UV damage when applied topically, these antioxidants may provide extra protection against the sun’s scorching rays when taken internally. Some natural healthcare providers recommend taking 1,000 mg. of vitamin C and 800 IU of vitamin E one hour before heading out into the sun.

References:

Hanson KM. Sunscreen enhancement of UV-induced reactive oxygen species in the skin. Free Radical Biology and Medicine. 2006;41: 1205-1212.

Nichols JA. Skin photoprotection by natural polyphenols: anti-inflammatory, antioxidant and DNA repair mechanisms. Archives of Dermatological Research. 2010;302:71-83.

Schlumpf M. In vitro and in vivo estrogenicity of UV screens. Environmental Health Perspectives. 2001;109:239-244