Anitoxidents help protect against sun's rays, study says

March 1, 2000
Web posted at: 11:33 AM EST (1633 GMT)

In this story: Damaging -- and deadly -- rays A debate surfaced No recommendation yet RELATEDS

(WebMD) -- Don't pack away that sunscreen just yet. A new study providing evidence of antioxidants' ability to shield the skin from sun damage may not be enough for doctors to endorse them as a preventive measure against sunburn and skin cancer.

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But the results do show that taking some antioxidant supplements may make a small difference in shielding people from sunburn-causing ultraviolet rays. Published in this month's issue of the American Journal of Clinical Nutrition, German researchers found that people who took daily doses of 25 mg of carotenoids (vitamin A-like substances) with or without 335 mg of vitamin E fared slightly better when exposed to ultraviolet rays than they did when not taking any supplements at all.

After eight weeks, researchers tested the 22 fair-skinned men and women in the 12-week study. Those who took the carotenoids alone reduced their sunburn reaction, equaling a sun protection factor (SPF) of 2.4. Adding vitamin E to the regimen increased the protection slightly more, but only to 3.0 SPF.

"What you do get with these oral carotenoids is an increase in your (skin) protection," said Wilhelm Stahl, Ph.D., a chemist at the University of Dusseldorf's Institute of Physiological Chemistry and lead author of the study. "This is not a very dramatic effect. So if you intend to have extensive sunbathing or a holiday at the beach, you'll have to do something additional."

That means using sunscreen and staying in the shade whenever possible. People who want the additional protection of vitamin E and carotenoid supplements should take them for at least six weeks before going out in the sun, Stahl said, adding that he believes vitamin E works synergistically with the carotenoids, boosting their effect.

Damaging -- and deadly -- rays

Sunburn is the skin's way of responding to an overload of ultraviolet light, which damages cells and leads to wrinkles. Ultraviolet rays can also trigger mutations in genes that can, in turn, lead to cancer. Scientists use changes in how the skin reacts to sun as a marker that indicates whether a particular treatment will reduce a person's risk of skin cancer.

Skin cancers are among the fastest-growing type of malignancies in the United States, with more than 1.3 million diagnoses last year, according to the American Cancer Society. Basal and squamous cell cancers are rarely fatal. However, melanomas, which are expected to strike 47,700 people this year, will likely claim 7,700 lives. Since the 1970s, the number of people with melanoma has increased an average of 4 percent each year.

A debate surfaced

For years, scientists have been intrigued by the relationship between cancer prevention and antioxidant vitamin supplements, such as vitamins A and E. But in most cases, hard evidence has been lacking.

James Spencer, M.D., head of dermatological surgery at Mount Sinai Hospital in New York City, said that researchers have shown that vitamin E -- now commonly added to sunscreens -- can offer a small amount of protection when applied to the skin. The effect of taking the vitamin orally, however, is less certain, he said.

While the results would be hard to translate into health recommendations, Stahl said they were interesting enough to merit the continued study of sun protection for the skin through diet.

No recommendation yet

But with so much conflicting data in the area, this study shouldn't encourage anyone to simply pop vitamins to ward off sunburn and skin cancers, Stahl acknowledged.

"There is a connection between sunburn and skin cancer," Stahl said. "However, this does not necessarily mean that preventing sunburns can lead to preventing skin cancer, and we don't claim carotenoids prevent skin cancer."

To underscore that point, in February the Archives of Dermatology published the results of a 12-year study involving more than 22,000 physicians. One group took 50 mg of beta-carotene every other day -- a quantity similar to that used in Stahl's study; the other group took a placebo. In the end, both physician groups had the same number of skin cancers.

That shouldn't be surprising, Spencer said, because the German study found such a small level of protection from the supplement. He said he finds their results interesting on a theoretical level.

"I like the idea that we could have a nutritional sunscreen that truly works, but we would like to see an SPF of 15 or greater," Spencer said.

Also skeptical of the study is Shelley Sekula, M.D., assistant clinical professor of dermatology at Baylor College of Medicine in Houston. The study didn't include a control group, and the researchers were aware of which patients were receiving which treatments.

"Maybe there'll be some future there, but this particular study doesn't demonstrate that," Sekula said. "None of us in dermatology would be satisfied with an SPF of two. It's a lot of work, a lot of taking medicine, for a very small gain, if anything."

© 2000 Healtheon/WebMD. All rights reserved.

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American Journal of Clinical Nutrition
American Cancer Society
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