Broccoli may outperform sunblock

WASHINGTON — George H.W. Bush: Call your dermatologist.

New research suggests broccoli, the vegetable that the former president famously demonized as inedible, can prevent the damage from ultraviolet light that often leads to skin cancer. And as Bush would surely appreciate, he would not even have to eat it.

In tests on people and hairless mice, a green smear of broccoli-sprout extract blocked the potentially cancer-causing damage usually inflicted by sunlight and showed potential advantages over sunscreens.

The product is still in early stages of development. Among other issues to be worked out is how best to remove the extract's green pigments, which do not contribute to its protective effects and would give users a temporary Martian complexion.

But scientists said the research represents a significant advance because the extract works not by screening out the sun's rays — which has the downside of blocking sun-induced vitamin D production — but by turning on the body's natural cancer-fighting machinery. Once stimulated, those mechanisms work for days, long after the extract is washed away.

"Ultraviolet radiation is probably the most universal and abundant carcinogen in the world," said Paul Talalay, of the Johns Hopkins School of Medicine in Baltimore. Talalay led the research, published in the online edition of the Proceedings of the National Academy of Sciences. And although the study stops short of proving that broccoli extracts can prevent human skin cancer, he said, it demonstrates "direct protection" against that carcinogen, which contributes to the 1 million U.S. skin-cancer cases seen annually.

"It's very important work," said Michael Sporn, a professor of pharmacology at Dartmouth Medical School, who for nearly two decades headed the National Cancer Institute's program on cancer prevention by means of natural products.

"The use of dietary substances, like the antioxidant vitamins C and E, has been pretty much a colossal failure for protection against almost any kind of human disease," Sporn said, "because when you eat them they don't go where you want them to ... and as soon as your body uses them up, they're gone."

By contrast, he said, boosting production of the body's own cancer-fighting mechanisms "is a new and promising approach."