The benefits of using sunscreen when heading outdoors are well established - protection from overexposure to the harmful effects of the sun, prevention of prematurely aging skin and defense against future skin cancer. Ongoing research about ultraviolet (UV) radiation and its effects on the skin, show how sunscreens may play an increasingly important role in defending the skin.
Speaking at ACADEMY '05, the American Academy of Dermatology's (Academy) summer scientific session in Chicago, dermatologist Elma D. Baron, M.D., an assistant professor of dermatology at Case Western Reserve University, Cleveland, Ohio, discussed how sunscreen benefits the skin now and what it may be able to do in the future.
"The most important thing to know about sunscreen is that, regardless of skin type and ethnicity, everyone needs to use it," advised Dr. Baron. "For basic protection year-round, the American Academy of Dermatology recommends using a broad-spectrum sunscreen - one that protects from both ultraviolet A (UVA) and ultraviolet B (UVB) rays - with a sun protection factor (SPF) of at least 15."
Sunscreens are designed to aid the body's natural defense mechanisms in protecting against harmful UV radiation from the sun. They work by absorbing, reflecting or scattering the sun's rays on the skin. The SPF of a sunscreen is calculated by comparing the amount of time needed to produce a sunburn on sunscreen-protected skin to the amount of time needed to cause a sunburn on unprotected skin. Higher SPF sunscreens offer greater protection from sunburn, which is caused mostly by UVB rays.
Currently, the SPF number on sunscreens only reflects the product's screening ability to protect against UVB rays. At present, there is no approved rating system by the Food and Drug Administration (FDA) that identifies UVA protection. Therefore, Dr. Baron advised looking for sunscreen ingredients which are broad-spectrum (providing UVA and UVB protection). Ingredients that afford good UVB protection are found in almost all sunscreens. Examples of ingredients that afford good UVA protection are titanium dioxide, zinc oxide and avobenzone (Parsol 1789).
"The ingredients within a sunscreen and its SPF number will give consumers an idea of the product's capacity to prevent sunburn, but they do not say much about a product's ability to protect against other harmful effects of UV light," said Dr. Baron. "In the future, sunscreen may be able to prevent UV radiation-induced immune suppression and perhaps prevent the development of skin cancer and photoaging."