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AAD Addresses Vitamin D-Sun Myths

Posted: November 25, 2009

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While UV radiation is one source of vitamin D, dermatologists argue that it is not the best source because the benefits of obtaining vitamin D through UV exposure cannot be separated from an increased risk of skin cancer. Instead, the Academy recommends that an adequate amount of vitamin D should be obtained from a healthy diet that includes foods naturally rich in vitamin D, such as dairy products and fish, foods and beverages fortified with vitamin D, and vitamin D supplements.

“Although studies showing the benefits of increased vitamin D intake have caused some to propose ‘sensible sun exposure’ or intentional sun exposure as a cost-effective method for preventing vitamin D deficiency, increased sun exposure is not the answer,” said Dr. Tanzi. “UV radiation is the most preventable risk factor for the development of skin cancer, which is the most common form of cancer in this country. There are more than an estimated one million new cases of skin cancer every year. Despite this fact, there remains a tremendous amount of misinformation about UV exposure – especially in relation to vitamin D.”

Myth: All sunscreens are created equal.
While on the surface most sunscreens may look the same, they are in fact quite different. One of the things that makes sunscreens different is the level of protection from UV exposure that they provide. Dr. Tanzi explained that a common misconception is that the SPF rates the degree of protection from both UVA rays, which pass through window glass, penetrate into the deepest layer of the skin and are associated with premature aging and melanoma, and UVB rays, the sun’s burning rays, which are blocked by window glass, are the primary cause of sunburn, and also are linked with skin cancer. In fact, the SPF number on sunscreens only reflects the product’s ability to deflect the sun’s burning rays, or UVB. Sunscreens labeled broad-spectrum provide coverage against both UVA and UVB light.

“SPF may create a false sense of security about the level of protection a person is getting, because many sunscreens do not adequately protect against harmful UVA rays,” said Dr. Tanzi. “The main challenge in providing effective protection from UVA rays is that traditional chemicals used in sunscreens that absorb UVA light degrade quickly and become ineffective.”

Fortunately, there are ingredients that can be added to traditional sunscreen ingredients to keep them stable and provide broad-spectrum protection. For example, Dr. Tanzi noted that the ingredient oxybenzone can help stabilize avobenzone—one of the best absorbers of UVA rays that, while highly effective, breaks down quickly, which provides a longer duration of effective protection from UVA rays. Other effective ingredients that help provide broad-spectrum UV coverage include ecamsule, cinoxate, menthyl anthranilate, octyl methoxycinnamate, octyl salicylate, and sulisobenzone.