Researchers from the Harvard School of Public Health and the Karolinska Institute have found no association between acrylamide intake in foods and the risk of breast cancer among Swedish women.

The findings appeared in the March 16, 2005, issue of the Journal of the American Medical Association.

In 2002, the Swedish National Food Administration first reported the discovery of acrylamide in several commonly eaten foods. The World Health Organization has classified acrylamide as a probable human carcinogen, based chiefly on experimental data.

Acrylamide appears to form as a result of a reaction between specific amino acids and sugars found in foods when heated to high temperatures. It is found in foods such as potato chips, French fries, cereals, breads, biscuits, coffee and meatballs, among others.

The researchers found that the amount of acrylamide eaten in the diet did not pose an increased risk of breast cancer among the women in the study.

Animal and laboratory studies in the past have shown higher levels of certain types of tumors in rats, including mammary gland tumors; however, they were exposed to levels 1,000 to 100,000 times greater than levels humans are exposed to through diet.

The researchers assessed acrylamide intake of more than 43,000 women, including 667 breast cancer cases, who were enrolled in the Swedish Women's Lifestyle and Health Cohort. Acrylamide intake was determined from food frequency questionnaires reported by the women in 1991; the women's health status was tracked via national health registers until the end of 2002.

The average daily acrylamide intake among the participants was 25.9 micrograms per day. Less than 1.5% of the women consumed more than 1 microgram of acrylamide per kilogram of body weight per day, a level used in risk assessment models.

The foods that contributed the most to acrylamide intake were coffee (54% of acrylamide dose), fried potatoes (12% of dose) and crisp bread (9% of dose).

Comparing the women in the study who had the lowest daily acrylamide intake, the researchers found no significant increased risk of breast cancer among the women whose intake was higher. Additionally, the researchers did not find an increased risk of breast cancer among study participants who had greater intakes of specific foods known to contain acrylamide.

Lorelei Mucci, lead author of the study and a researcher in the Department of Epidemiology at the Harvard School of Public Health and Channing Laboratory at Brigham and Women's Hospital, said, "This is the first prospective study to examine whether acrylamide intake through foods is associated with an increased risk of cancer. It's reassuring to see that the study suggests that the amount of acrylamide consumed in the Swedish diet is not associated with an excess risk of breast cancer."

She added, "Given the widespread public health implications of acrylamide, however, it is important to examine the risk associated with other cancers as well as neurological conditions"

Previous research by Mucci and colleagues found that dietary levels of acrylamide do not increase the risk of bladder, large bowel, and kidney cancer in humans (British Journal of Cancer, 2003;88(1):84-9)

The research was funded by grants from the U.S. Department of Defense Congressionally Directed Medical Research Program and the Swedish Cancer Society.