What is in your sunscreen?

The Environmental Working Group says sunscreen is not necessarily effective against the much more common basal cell cancers (treatable at 80 percent) or melanoma (potentially deadly at 4 percent).

by Mary Budinger — 

The latest recommendations for sunscreens from the American Academy of Dermatology (AAD) contradict the recommendations of the Environmental Working Group (EWG), a nonprofit organization that advocates for health protective policies. Three ingredients on which the two groups disagree are oxybenzone, retinyl palmitate and nanoparticles.

“Available peer-reviewed scientific literature and regulatory assessments do not support a link between oxybenzone in sunscreen and hormonal alterations or other significant health issues in humans,” stated Daniel M. Siegel, M.D., FAAD, president of the AAD. The FDA has approved oxybenzone in sunscreen for use on children older than six months.

The EWG points out, however, that oxybenzone comes with cautions. “Oxybenzone is found in more than half of the 814 beach and sport sunscreens in EWG’s 2012 database. Oxybenzone can trigger allergic reactions, is a potential hormone disrupter and penetrates the skin in relatively large amounts,” EWG states. “Some experts caution that it should not be used on children.” In the United States, oxybenzone has been detected in the blood of 96 percent of the population.

Retinyl palmitate, a form of vitamin A (retinol), serves as an antioxidant to improve product performance against the aging effects of UV exposure, or to enhance product aesthetic qualities. The AAD states that, “Despite recent concerns from in vitro (test tube) studies and one unpublished report using mice, topical and oral retinoids are widely prescribed to treat a number of skin diseases, such as acne and psoriasis, and there is no published evidence to suggest either increase the risk of skin cancer in these patients. In fact, oral retinoids are used to prevent skin cancers in high-risk patients, such as those who have undergone organ transplantation. Unlike more potent prescription forms of vitamin A, there is no evidence to suggest that use of sunscreen with retinyl palmitate poses comparable risks.”

However, EWG cites a 2009 study that suggests that retinyl palmitate, when applied to the skin in the presence of sunlight, may speed the development of skin tumors and lesions. “The evidence, while not definitive, is troubling,” the organization says. “The FDA study of the photocarcinogenic properties of vitamin A raises the possibility that it results in cancerous tumors when used on skin exposed to sunlight. Scientists have known for some time that vitamin A can spur excess skin growth (hyperplasia) and that in sunlight it can form free radicals that damage DNA.

In December 2010, the FDA and the National Toxicology Program teams published a joint draft report on the vitamin A study entitled “Photococarcinogenesis Study of Retinoic Acid and Retinyl Palmitate.” It concluded that retinyl palmitate resulted in earlier onset and greater numbers of skin lesions and squamous cell tumors — an interpretation consistent with EWG’s findings. Despite broad scientific agreement that vitamin A appears to be associated with carcinogenic activity, the FDA has delayed taking action to restrict the ingredient in sunscreens.”

Nanoparticles are the current answer to complaints that sunscreens with titanium dioxide and zinc oxide used to reflect sunlight are too thick and leave a pasty white film. When these minerals are converted into nanoparticles — smaller, lighter molecules of between 20 and 200 nanometers in size — they create lotions that are nearly clear and appear to vanish on the skin.

“While widespread use of nanotechnology in medicine is currently under evaluation,” the AAD states, “considerable research on the use of nanoparticles on healthy, undamaged skin has shown that the stratum corneum — the outermost layer of the skin — is an effective barrier to preventing the entry of nanoparticles into the deeper layers of the skin.”

EWG agrees that the minerals zinc oxide and titanium dioxide are among the best of the available sunscreen ingredients for American consumers and sunscreens that incorporate them tend to rate well in EWG’s guide. Zinc oxide and titanium dioxide are nonallergenic, do not break down in sunlight and do not disrupt the body’s natural hormones. EWG’s 2009 review of more than a dozen in vivo and in vitro studies found little to no skin penetration for nanoparticle zinc oxide and titanium dioxide on healthy human, pig and rodent skins.

But again, there are cautions. “EWG’s assessment of the comparative benefits of zinc and titanium sunscreens that might contain nanoparticles is not meant as an endorsement of all nano-scale products, nor of the manufacturing processes. Studies suggest that nanomaterials are toxic to fish and other aquatic life in the environment and can damage organs if they are absorbed through the skin, lungs or gut and enter the bloodstream. EWG urges consumers to avoid mineral-based sunscreens sold as powders or sprays because they could inhale nanoparticles, with unknown consequences. EWG urges manufacturers of mineral-based powder and spray products not to use nano-scale particles.”

We wear sunscreen because we want to avoid skin cancer. But does it work? EWG says regular sunscreen use has been shown to reduce risk for squamous cell cancer, which is treatable, but only 16 percent of skin cancers are this type. EWG says sunscreen is not necessarily effective against the much more common basal cell cancers (treatable at 80 percent) or melanoma (potentially deadly at 4 percent).

Ultraviolet (UV) radiation stimulates our bodies to make vitamin D. But a little goes a long way. UVA rays, which comprise perhaps 95 percent of the UV radiation that makes it to Earth, have a longer wavelength than UVB rays and go deeper into the skin. They give us both the tan we like and the wrinkles we do not. UVB rays burn us and are blamed for instigating skin cancer. Since sunscreen may give a false sense of security, the best protection is to wear clothing when in the sun for a long time.

Sources: www.aad.org/stories-and-news/news-releases/sunscreen-remains-a-safe-effective-form-of-sun-protection. http://breakingnews.ewg.org/2012sunscreen.

 

Mary Budinger is an Emmy award-winning journalist who writes about integrative medicine. 602-494-1999.

Reprinted from AzNetNews, Volume 31, Number 4, August/September 2012.

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