Published on October 16, 2010
Recent attacks on sunscreen by the Environmental Working Group (EWG) and the media have prompted some consumers to question sunscreen safety. In the following Q & A, Warwick L. Morison, MD, Professor of Dermatology at Johns Hopkins Medical School at Green Spring Station, MD, debunks the EWG’s claims. “The EWG has its own system for evaluating sun- screens, which is nothing more than junk science,” notes Dr. Morison, chairman of The Skin Cancer Foundation’s Photobiology Committee, an independent volunteer panel of experts on sun damage and sun protection.
Q: Can sunscreen cause melanoma?
Dr. Morison: Review of all studies from 1966 to 2003 shows no evidence of a relationship between sunscreen use and increased risk of melanoma, the deadliest form of skin cancer.
The increase in melanoma can be attributed to several factors, especially the growth of tanning. Both the sun and indoor tanning machines emit ultraviolet (UV) radiation, a proven cancer-causing agent.
Q: Are high SPFs and terms such as “broad-spectrum protection” misleading?
Dr. Morison: “Broad-spectrum” and “multi-spectrum” protection mean only that a sunscreen offers protection against parts of the UVA and UVB spectrums. The entire UV range is harmful, so broad-spectrum protection does not mean complete protection.
SPF — sun protection factor — refers specifically to how much protection is of- fered against UVB. An SPF 15 sunscreen screens out 93 percent of the sun’s UVB rays, while SPF 30 protects against 97 percent and SPF 50 98 percent. In most cases, SPFs beyond 50 are unnecessary.
Q: Do sunscreens fail to protect adequately against UVA radiation?
Dr. Morison: In the past, sunscreens focused almost exclusively on prevent- ing sunburn, which is primarily caused by UVB; high-SPF sunscreens were dedicated mainly to screening out UVB. Today, several good ingredients are devoted to UVA protection. To make sure you have effective UVA/UVB coverage, look for a sunscreen with an SPF of 15 or higher, plus some combination of the following UVA-screening ingredients: avobenzone, ecamsule, oxybenzone, titanium dioxide, and zinc oxide.
Q: Does sunscreen lead to vitamin D deficiency?
Dr. Morison: Solar UVB rays are a source of vitamin D, and UVB sunscreens are designed to filter them out. However, no study has ever shown that sunscreens lead to vitamin D deficiency. Just a few minutes in the sun produces as much vitamin D as the body can manufacture and excessive sun exposure actually depletes the body’s supply. Furthermore, the vitamin D benefits of sun exposure cannot be separated from its harmful effects: skin cancer, cataracts, immune system suppression, premature aging. The safest way to obtain vitamin D is through diet and supplements. [The Skin Cancer Foundation recommends 1,000 mg. of vitamin D daily.]
Q: Do the sunscreen ingredients oxybenzone and retinyl palmitate cause cancer?
Dr. Morison: There is no evidence that oxybenzone, which is FDA-approved and has been available 20 years, has any adverse health effect in humans.
Retinyl palmitate, a common sun- screen ingredient in trace amounts, is a form of vitamin A, and no scientific evidence shows that vitamin A causes cancer in humans.
The EWG based its criticisms of retinyl palmitate on an unpublished, unapproved 10-year-old FDA study of mice. As is standard practice, the FDA has held back the study because independent researchers have yet to review the data.