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Using Sun Blocks and Screens Can Make You Have a Healthier Summer

July 22, 1989|JULIE LOGAN and DR. DAVID C. RISH | Dr. David C. Rish is a clinical professor of dermatology at UCLA Medical Center in Los Angeles.

The description healthy tan is a contradiction in terms. Once you understand the sun's effects on your skin, you won't envy all those bronzed bodies you see.

Unprotected skin dries out, thickens and changes to a leathery texture. Aging begins on the surface of your skin and penetrates deeper, to cause fine lines, wrinkles, age spots and dilated blood vessels. These changes, called photoaging, are caused by the sun over a period of time.

More important, tanning can be hazardous to your health. The sun causes skin cancers, with perhaps the greatest risk coming from sunburn. Some skin cancers can be disfiguring, while others can be fatal. The death rate from malignant melanoma reached 5,800 in 1988, according to American Cancer Society estimates.

If you think these warnings sound like old news, the sad truth is that people aren't heeding them. Skin cancer statistics keep climbing year after year, and the Skin Cancer Foundation estimated more than half a million new cases in 1988.

But skin cancer and many of the effects of photoaging are preventable. For 100% protection, you would have to hide indoors with the blinds closed or cover your body in zinc oxide. But sunscreens and sun blocks make summer a lot easier on your skin. At the same time, standards of beauty are changing, so that we now admire untanned skin.

Guide to Protection

Your guide to sun protection is a rating system of SPFs (sun protection factors) used by the Food and Drug Administration. Products with an SPF 15 or above are called sun blocks; those with lower SPFs are considered sunscreens. The active ingredients in these products absorb ultraviolet radiation before it reaches your skin.

The number tells you how much time you have before you burn. Without protection, your skin starts to burn after 10 minutes, so an SPF 15 extends your safe sun exposure 15 times longer. In other words, you get 150 minutes of sun protection. For continued safe sunning, reapply the product before that time expires.

You've probably noticed the phenomenon of escalating SPFs. SPF 15 is still the highest designation on the FDA's scale, but today you'll see products with SPFs as high as 50. Manufacturers claim that some products with more active ingredients or a combination of active ingredients provide extended sun protection.

These super sun blocks are not exactly what you might expect. An SPF 15 gives you 90% protection, allowing some rays to come through; hence the burning time limit. But an SPF 30 won't double your protection. The higher SPFs are less accurate insofar as how long they extend your coverage. Regulations may change, but, at present, SPFs higher than 15 are not standardized, so you don't know exactly how much more protection you're getting.

Rest assured that the higher numbers don't translate into harsher chemicals. Super sun blocks won't harm your skin, but you may be sensitive to such ingredients as alcohol, perfumes or preservatives.

PABA Reactions

Reactions to PABA--para-aminobenzoic acid, one of the most effective sunscreen ingredients--are common, causing an itchy, red, bumpy rash. Using a PABA-free product can help.

Sunscreens have been getting some bad press lately. Some studies suggest that long-term use of sunscreen can cause Vitamin D deficiency. These studies revealed a problem among the elderly, who already have a decreased capacity to synthesize Vitamin D. The deficiency was corrected with vitamin supplements.

However, sunscreens don't block all the ultraviolet light your skin absorbs, and, among the general public, the dangers of skin cancer far outweigh the possibility of vitamin deficiency.

The SPF system only rates a product's ability to absorb the short UVB rays, which cause burning. PABA-based sunscreens are most effective for stopping these rays, but they don't screen out the longer rays of UVA radiation.

Tanning machines work on the same principle. They eliminate most of the burning rays and use UVA rays to tan your skin. But don't think that a few weeks at a tanning salon can spare your skin the damage from your first summer sunburn. Highly concentrated doses of UVA radiation from machines could be worse for your skin than the sun.

More Radiation

"Tanning booths produce much more radiation per unit of time than you would get from the sun," says John Epstein, MD, a clinical professor of dermatology at UC San Francisco who specializes in photobiology. "These rays aren't the ones that cause sunburns when you go to the beach, but they can augment the damage done. In large enough amounts, UVA rays can produce skin cancers themselves."

Large enough amounts could be what it takes to get a tan at a salon. Several counties and some states have passed legislation requiring consumer warnings about the health hazards of tanning machines.

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