- ORLANDO, Fla. -- What you eat may play a role in your risk of developing
skin cancer, the most common malignancy in the U.S. Ultraviolet light
has long been considered the major cause of most skin cancers, so prevention
has focused on staying out of the sun and wearing protective clothing and
sunscreen. But studies in recent years have indicated that several nutritional
factors also may play a role, according to Harvey Arbesman, M.D., a dermatologist
and University at Buffalo clinical assistant professor in the departments
of Social and Preventive Medicine and Dermatology. Primary among these
factors, Arbesman said, are dietary fat and antioxidant vitamins and minerals.
Half of all new cancers diagnosed in the U.S. are skin cancers. Melanoma,
the most serious form of skin cancer, accounts for only about 4 percent
of total skin cancers, but is more prone to spreading and can be fatal.
The remaining 96 percent are labeled nonmelanoma skin cancers, and they
account for an estimated 1 million new cases of skin cancer per year.
Arbesman reviewed findings of scientific literature dealing with the relationship
between nutrition and these nonmelanoma cancers here Feb. 27 at the annual
meeting of the American Academy of Dermatology and discussed the role of
nutritional factors in treating patients at risk. The majority of nonmelanoma
skin cancers are basal cell carcinomas, which rarely spread, but can cause
significant local damage that requires surgery, Arbesman said. The remaining
nonmelanomas are squamous cell cancers, which pose a slightly increased
risk of spreading but are usually easily treated, he noted. "Clinical
trials have demonstrated that a low-fat diet can reduce the development
of new precancers called actinic keratoses, as well as basal cell and squamous
cell carcinomas," he said. "One recommendation for patients at
risk of developing these growths is to consume a diet containing no more
than 20 percent of calories from fat." Risk factors for developing
new nonmelanoma skin cancers include a history of precancerous lesions,
fair skin, red or blond hair, early severe sunburns and a history of intense
sun exposure. Antioxidant vitamins with the ability to neutralize damaging
free-radical molecules produced as a byproduct of normal metabolism and
by ultraviolet light have been shown to be potentially important in protecting
against skin cancers. "Some animal and epidemiologic studies have
shown that a higher intake of Vitamin C can reduce the development of nonmelanoma
skin cancer," Arbesman said. "Another recommendation for persons
at risk might be to increase their intake of foods rich in Vitamin C to
consume 500 milligrams per day. They also may benefit from increasing their
intake of foods containing beta carotene, such as carrots, sweet potatoes
and broccoli." Vitamin E has been shown to reduce the development
of ultraviolet light-induced tumors in animals, he reported, but because
Vitamin E can interact with other medications, Arbesman cautioned against
taking supplements without consulting a physician. Selenium, a mineral
that acts as an antioxidant, also may play a role in reducing the risk
of skin cancer. Selenium is available liberally in food sources such as
brown rice, whole grains and Brazil nuts. One single Brazil nut provides
120 micrograms of the mineral, exceeding the 100 microgram recommended
daily dose, he noted. Arbesman cautions against taking selenium supplements
because of potential adverse side effects, which include blackened or fragile
fingernails, irritability, nausea and vomiting. "These nutrients
that have been shown to have an impact on nonmelanoma skin cancers are
already part of most diets, and they benefit other organs as well,"
he said. "Everyone can benefit from eating more fruits and vegetables."
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