May 9, 2008 -- The chemical acrylamide -- found in French fries, potato chips, and even bread and coffee -- is known to cause cancer in animal studies. Now new research from the Netherlands suggests that it may do the same in humans.
Acrylamide is used in the manufacture of cosmetics, plastics, and food packaging. Until just a few years ago, cigarette smoke and occupational exposures were considered the main sources of exposure to the compound.
But in 2002, researchers in Sweden reported that the chemical is also present in certain foods, especially starchy foods that are fried or baked.
"It is clear that our foods have contained this compound since man started cooking with fire," he says.
Acrylamide and Cancer
What is less clear is whether dietary exposure to acrylamide poses a health risk.
In an effort to address this question, researchers from Maastricht University in the Netherlands examined data from a large Dutch study on diet and cancer begun in 1986.
Almost 121,000 participants between the ages of 55 and 70 completed a detailed food-frequency questionnaire designed to determine their eating habits. The answers, combined with a separate database, were used to estimate acrylamide intake.
For this study, the researchers focused on acrylamide intake and cancers of the kidney, bladder, and prostate. After a follow-up of 13 years, there were 339 cases of kidney cancer, 1,210 cases of bladder cancer, and 2,246 cases of prostate cancer.
On average, people in the study ate about 22 micrograms of acrylamide a day. To put this amount in perspective, a 2.5-ounce serving of French fries contains about 25 micrograms of the chemical.
The participants were divided into five categories of acrylamide consumption. People who ate the highest amounts of the chemical were found to have a 59% greater risk for kidney cancer than those who ate the least, researcher Janneke G. Hogervorst tells WebMD.
The risk appeared to be especially strong for smokers.
Acrylamide consumption did not appear to be associated with an increased risk for cancers of the bladder or prostate.
In findings reported last year using the same database and study design, Hogervorst and colleagues reported that postmenopausal, nonsmoking women whose diets included the most acrylamide had significantly increased risk for ovarian and endometrial cancer than women whose diets contained the least.
That study was published last December in the journal Cancer Epidemiology Biomarkers and Prevention. The latest findings appear in the May issue of the American Journal of Clinical Nutrition.
"In the future we hope to look at many more cancer types," Hogervorst says. "We also hope that other researchers will do similar studies to expand on our research."
Acrylamide in U.S. Diet
But a critic of that research tells WebMD that the Dutch studies and those of similar design do little more than confuse the public.
"They went looking for an association in this study and they found one," says Jeff Stier. "But people should not confuse association with causation."
Stier is associate director of the American Council on Science and Health, a consumer education group.
The FDA has reported that 100% of Americans consume acrylamide, but exposure levels do not appear to be increasing.
Clemens, who is a spokesman for the American Society for Nutrition, points out that estimates by the FDA and the World Health Organization suggest that typical dietary exposures do not come close to the exposures that were shown to cause tumors in lab animals.
"The exposures in the animal studies were [the equivalent] of about 300 times the amount that a typical person would consume," he says.
He adds that there are still plenty of good reasons for limiting French fries and potato chips, noting that "balance, moderation and variety are the keys to a healthful lifestyle."