VILLIGER: With summer approaching, people are stocking up on their favorite sunscreens to fend off the sun's damaging ultraviolet rays. But some Swiss scientists warn that the UV-absorbing chemicals used to protect skin cells may pose hormonal risks. Researchers studied six chemicals commonly used in sunscreens and other cosmetics. Five of the six UV screens they examined behaved like the hormone estrogen in lab tests, speeding up the growth of breast cancer cells. Three of the chemicals also quickened the pace of sexual development in rats when mixed with their feed. Even applying the chemicals to the rats' skin in concentrations allowed in commercial sunscreens disrupted normal reproductive development. Researchers don't know whether these dosage levels have similar effects on people, but they are concerned because the hormone-mimicking chemicals can build up in our bodies and have been found in breast milk. Also worrisome, the UV-absorbers can enter the food chain when fish accumulate chemicals that wash off sunscreen-coated swimmers. Scientists aren't yet advising us to abandon sunscreens, which still provide the best defense against sun-damaged skin. They do suggest that until we know more about the effects of UV-absorbing chemicals, zinc oxide, which doesn't contain the additives, may be your best bet. As long as you don't mind a bright white nose. That's this week's health note. I'm Maggie Villiger.
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