Sunscreen numbers are debated

Sunblocks: Some fear that an FDA ruling limiting claims on product labeling may do more harm than good.

August 01, 1999|By Karen Uhlenhuth | Karen Uhlenhuth,Knight Ridder / Tribune

There's nothing wrong with wearing sunscreen -- as long as you wear something else with it like a hat with a very wide brim. Long pants and a long-sleeved shirt wouldn't be a bad idea, either.

Sunscreens do provide some protection against damage caused by the sun, but just how much is open to question. And many of the nation's dermatologists are concerned that a recent decision by the federal Food and Drug Administration regarding labeling of sunscreens will result in only more skin cancers and sun- related skin damage.

In May the FDA ruled that sunscreen manufacturers have two years to change the labels on their products to indicate sun protection factors of no more than 30. Currently some sunscreens claim SPFs of 45, 50 and even 60.

The regulatory agency decided to prohibit claims higher than 30 SPF because manufacturers "haven't got the science to show it's really effective," according to an FDA spokeswoman.

"The best preparations on the market will probably go away due to this regulation," said Mark Naylor, a cancer biologist and an assistant professor of dermatology at the University of Oklahoma.

The American Academy of Dermatology is concerned that the ruling will result in less effective sunscreens, reduced efforts to develop more potent sunblocks and a subsequent increase in the already-escalating rates of skin cancers among Americans.

"Sunscreens are an essential weapon in the fight against skin cancer," said Darrell S. Rigel, president of the American Academy of Dermatology. "We want consumers to have their choice of the best available protection in sunscreens."

It's pretty clear that sunscreens with an SPF of 15 or more protect against sunburn, Naylor said. But there's more to the sunscreen story than sunburn prevention.

Sun exposure causes skin cancer and premature aging and suppresses the body's immune response as well, Naylor said. So although a 30 SPF product may adequately protect against sunburn, it may not provide maximum protection against the other harmful effects of sun exposure, he said.

One study funded by the New Jersey-based Schering-Plough Corp. found that an SPF 45 sunscreen provided significantly better protection against immunosuppression than did an SPF 30 product, Naylor said.

Some research also has indicated that although SPF 15 and SPF 30 provided similar levels of protection against burning, the subjects using the SPF 15 product had more frequent cell mutations, a precursor to cancerous growth, Naylor said.

It's pretty clear, Naylor said, that "bad things are going on even though you're preventing sunburn."

So there's a health imperative for more research into sunscreens and the development of more effective products. But Naylor and other dermatologists worry that companies won't conduct such research if they aren't allowed to promote the resulting products as actually being more effective.

Higher SPF-rated sunblocks are needed for another reason, according to Naylor and the dermatologists association: Many people don't apply enough sunscreen to attain the level of protection promised by the SPF rating on the label.

A study published in the Archives of Dermatology reported that sunscreen users overall apply only about half as much sunscreen as needed to obtain the full protection indicated by the product's sun protection factor, according to the dermatology association.

An SPF 30 sunblock applied at half the required level provides the blocking effect of an SPF 15, according to the association.

Naylor said adequate coverage of one's face, neck and forearms would require about 2 teaspoons of sunscreen.

Lower SPF ratings would likely also mean less protection against ultraviolet A waves, Naylor said. Ultraviolet B waves have long been understood to cause sunburn and other kinds of skin damage. Blocking them has long been the goal of sunscreen formulations, Naylor said. But only recently has the lesser but still significant damaging effect of ultraviolet A waves been understood.

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