Researchers say that acrylamide, a substance found in various cooked and fried foods, does not raise the risk of cancer in humans.
Acrylamide raised alarm bells last year when researchers found high amounts of it in foods. They called it a likely carcinogen and "a serious problem." They weren't sure, however, how serious a problem it was in people.
The new study, the first to look at the role of high levels of dietary acrylamide in humans, appears in the Jan. 28 issue of the British Journal of Cancer.
"We weren't surprised," says Lorelei Mucci, lead author of the study, which she completed while a doctoral student at the Harvard School of Public Health and the Karolinska Institute in Stockholm, Sweden. "We had hypothesized that probably doses in foods were low enough that the body could detoxify them."
Jeff Nedelman, a spokesman for the Snack Food Association in Vienna, Va., a trade group, termed the results "cautiously encouraging."
The International Agency for Research on Cancer (IARC) added acrylamide to its list of probable human carcinogens in the 1980s, says Mucci. That decision was based largely on animal and laboratory -- not human -- studies.
A brouhaha erupted in April of last year when unexpectedly high levels of the substance were found in foods such as french fries, potato chips, cereals, and bread. Late last year, the U.S. Food and Drug Administration found that acrylamide levels varied wildly even in different packages of the same brand of potato chips.
Acrylamide forms during the cooking process. It is part of the reaction between amino acids and sugars when high-starch foods are heated to high temperatures.
"We are talking about the basic cooking process. We're not talking about adding an ingredient," Nedelman says. "The reaction occurs whether you're commercially making a product or whether you're making a grilled cheese sandwich, toast, or baking bread at home."
In the new study, Mucci and her colleagues in Sweden and Boston looked at the diets of 987 patients with bladder, bowel, or kidney cancer and 538 healthy individuals over a five-year period to see if they could find a correlation between acrylamide-high foods and cancer. A total of 188 different types of food were assessed.
At the end of the study, the researchers found no increased risk for these types of cancer, even at the highest levels of acrylamide consumption. Moreover, there was a reduced risk for large bowel cancer, possibly explained by the fact that many of the foods containing acrylamide are cereals high in fiber.
Although the research doesn't rule out other harmful effects of acryalmide, the three types of cancer studied here "are probably the organs you would expect to see an effect on because of the way acrylamide is detoxified in the body," Mucci says.
"This sheds important new light on the key toxicological question, which is how much of this stuff actually gets into the bloodstream and does it present any risk to consumers," Nedelman adds. "The very preliminary evidence, which this study is the first to confirm, is that there is a natural detoxification process under way so there is no threat."
There is some evidence indicating that acrylamide may cause neurological problems, but this is far from proven.
Although the current results should be re-confirmed, Mucci is confident that researchers are on the right track. "When the study came out last year [finding high levels of acrylamide in certain foodstuffs], there was a lot of concern," Mucci says. "It was important for these questions to be addressed."
For more on acrylamide in food, visit the Joint Institute for Food Safety and Applied Nutrition or the U.S. Food and Drug Administration.