There is probably no link between levels of acrylamide, a chemical commonly found in certain cooked foods, and breast cancer risk, according to a large, new study presented recently in Boston at a meeting of the American Chemical Society.

The research, presented by Harvard School of Public Health epidemiologist Lorelei A. Mucci, involved 100,000 women already participating in the ongoing Nurses' Health Study. The researchers administered three separate food intake questionnaires over the 16 years during which they followed the women and correlated their dietary consumption of acrylamide with development of breast cancer. Mucci's previous research had already shown no link between acrylamide and colo-rectal cancer, bladder cancer, and renal cancer. A different study Mucci published in 2005 followed 43,000 Swedish women and also found no link between dietary acrylamide and breast cancer.

"This is good news," said Dr. Michael Thun, who heads epidemiological research for the American Cancer Society. "But I'm sure these studies won't end the concern about acrylamide and cancer because I have never seen concern about an environmental contaminant go away because of two or three studies." On the other hand, he noted, there are other health reasons to avoid lots of french fries, including consumption of excess fat and calories. "If there were the same level of concern about the other health effects of french fries as there has been about acrylamide, we'd all be thinner and healthier."

The concern about acrylamide in the diet surfaced in 2002 when Swedish researchers first reported that acrylamide is formed naturally when foods such as potatoes, which are rich in an amino acid, are cooked at high temperatures in the presence of sugars. Interestingly, said Mucci, boiling potatoes does not raise temperatures enough to form acrylamide, but baking and frying do. Breads and cereal also contain it.

Acrylamide is classified by the World Health Organization and others as a probable human carcinogen. But animal studies used doses 1,000 to 100,000 higher than those in the human diet. At levels humans are exposed by diet, acrylamide "is not sufficient to cause cancer," concluded Mucci.