The findings, claimed to be from the largest epidemiological study to date exploring the possible link between acrylamide and cancer in humans, were presented at the 234th national meeting of the American Chemical Society.
"At levels consumed in the diet, it appears unlikely that acrylamide in foods is related to breast cancer risk," said Lorelei Mucci, from Channing Labs at Brigham and Women's Hospital and Harvard School of Public Health in Boston.
"Although we do not rule out that very high levels of acrylamide could cause cancer, it appears that at the levels found in the diet, it is unlikely," she added.
Acrylamide is a carcinogen that is created when starchy foods are baked, roasted, fried or toasted.
It first hit the headlines in 2002, when scientists at the Swedish Food Administration first reported unexpectedly high levels of acrylamide, found to cause cancer in laboratory rats, in carbohydrate-rich foods.
Since the Swedish discovery a global effort has been underway to amass data about this chemical.
More than 200 research projects have been initiated around the world, and their findings co-ordinated by national governments, the EU and the United Nations.
Mucci noted that the average daily dietary intake of acrylamide in adults is 0.5 micrograms/kg body weight, with intakes reportedly higher among children.
The study followed 100,000 U.S. nurses over 20 years and measured dietary habits using periodic questionnaires.
Over 3000 cases of breast cancer were diagnosed during the course of the study, with no statistically significant association observed between acrylamide intake and breast cancer.
"Although we found no significant association between acrylamide in the diet and increased risk for breast cancer among the study participants, it is quite important to stress the importance of eating a healthy diet that includes foods low in saturated and trans fats, unlike French fries and potato chips," said Mucci.
The results reported by Mucci at the ACS meeting contradict those of animal studies, where high acrylamide doses led to increased rates of cancer of the thyroid, testicles, breasts, and uterus.
The suggested several possible explanations to account for the differences between animals and human studies, including animal exposure being 1,000 to 100,000 times higher than what humans are exposed, and the animal studies provided the acrylamide from water, unlike humans who obtain acrylamide from food sources.
Mucci also indicated that the possibly may also exist that humans effectively detoxify acrylamide when consumed at dietary levels.
In addition, the epidemiological studies may not have sufficient statistical power to adequately detect the cancer risk, she said.
"The story of dietary acrylamide and cancer risk in humans is still emerging, and additional epidemiological studies examining other cancers and in additional populations are warranted, including biomarker assessment of acrylamide exposure," stated Mucci.
Commenting independently on the research, Henry Scowcroft, senior information officer at British charity Cancer Research UK, told FoodNavigator.com: "Despite being a carcinogen in the laboratory, population-based studies have repeatedly shown that our everyday exposure to acrylamide in food is too low to be of concern.
"And several other large studies have found no increase in cancer risk in people exposed to above-average levels of acrylamide, such as food industry workers.
This new study adds to that evidence.
"However, it's worth pointing out that chips and other fried starchy foods are usually full of fats and obesity does increase your risk of several cancers," stated Scowcroft.
While Mucci's findings may suggest an easing of fears, Richard LoPachin Jr., from the Albert Einstein College of Medicine in New York, told the ACS meeting that dietary acrylamide may play a role in Alzheimer's progression.
LoPachin Jr.'s laboratory studies suggest that chronic dietary exposure to acrylamide may damage nerve cells in the brain, thereby potentially spurring the development of neurodegenerative disease, like Alzheimer's.
He noted that the chemical structure of acrylamide is similar to acrolein, a chemical found in increased levels in brains of patients with Alzheimer's and other neurodegenerative diseases, and called for human studies to further investigate the possible link.
Source: 234th national meeting of the American Chemical Society Abstract AGFD 082, Tuesday, August 21, 2007 "Acrylamide intake through diet and human cancer risk" Author: Lorelei A. Mucci Part of the symposium, "Chemistry and Toxicology of Acrylamide"
Abstract AGFD 079, Tuesday, August 21, 2007 "Molecular mechanisms of neurotoxicity:
Acrylamide targets thiolate sulfhydryls of catalytic triads" Author: Richard M. LoPachin Jr