New York, NY, February 12, 2001-Arsenic, a cancer-causing metal that poisons millions of people worldwide, exerts its harmful effects by boosting the body's production of damaging chemicals called free radicals, Columbia researchers report.
The new research, published in the Feb. 13 issue of Proceedings of the National Academy of Sciences, adds to growing evidence that nutrients called antioxidants, which eliminate free radicals, may help prevent cancer and other illnesses caused by such environmental toxins as arsenic, cadmium, and asbestos. Sources of antioxidants include vitamins and micronutrients commonly found in the human diet, such as vitamin C, vitamin E, and selenium.
"Arsenic is among the top environmental contaminants on the EPA Superfund list," says Dr. Tom K. Hei, the lead author of the study. "This piece of research provides the first clear-cut evidence that an environmental carcinogen acts predominantly through a free-radical pathway." Dr. Hei is professor of radiation oncology and public health at the Center for Radiological Research at Columbia University's College of Physicians and Surgeons.
"If we understand how arsenic causes cancer, we'll have better means of prevention." Antioxidants are a leading candidate for such preventive measures, he said.
The study, which also involved P&S dermatology researchers and researchers at Albert Einstein College of Medicine and Colorado State University, showed that cells cultured in the laboratory sharply increased their free radical production within five minutes of being exposed to an arsenic compound. The compound, sodium arsenite--the main toxic form of arsenic in the environment--also boosted the rate of mutations among the cells. Mutations are a key step in cancer development. The mutation rate shot up still higher when researchers added a chemical that reduced the cells' production of natural antioxidants. This was consistent with previous research suggesting that antioxidants can p
Contact: Carolyn Conway-Hoare
Columbia University Medical Center