Acrylamide and Cancer Risk: What Do Human Studies Say?

There's been much debate over whether acrylamide, a chemical compound found in some fried, roasted, and baked foods, can really cause cancer in humans. Animal studies using high doses of acrylamide have shown a strong link between ingestion of this controversial chemical and cancer risk. As a result, acrylamide has been classified as a probable human carcinogen. However, the vast majority of population-based human studies have not found any significant link between an increased risk of cancer and high dietary levels of acrylamide. Here's the scoop on the latest research:

Studies That Have NOT Found a Link

A small Swedish case-control study published in the British Journal of Cancer in 2003 found no link between the levels of acrylamide in fried foods and the incidence of liver, kidney and bowel cancers. Survey questionnaires were mailed to 692 controls, and 1452 cancer patients.

In 2009, another group of Swedish researchers carried out a larger study involving over 45,000 male subjects. This population-based study found no evidence that dietary acrylamide in amounts typically consumed by Swedish men is associated with an increased risk of colorectal cancer. The researchers obtained their data through food frequency questionnaires and published their findings in the European Journal of Cancer.

A group of Italian scientists used a series of hospital-based case-control studies conducted in Italy and Switzerland between 1991 and 2000 to analyze the relation between intake of fried/baked potatoes and cancer risk (fried and baked potatoes are among the highest food sources of acrylamide). This large-scale study assessed the risk for various types of cancer – including cancers of the oral cavity and pharynx, large bowel, esophagus, larynx, breast, and ovaries – but found no association between the consumption of fried/baked potatoes and cancer risk. This study was published in the International Journal of Cancer in 2003.

A 2008 study involving over 60,000 Swedish women in the Women's Lifestyle and Health Cohort found no link between breast cancer risk and a higher dietary intake of acrylamide. The study assessed breast cancer risk overall as well as by estrogen receptor (ER) and progesterone receptor (PR) status. The findings appeared in the American Journal of Epidemiology.

A 2009 study on over 90,000 premenopausal women in the US also found no relationship between dietary acrylamide intake and breast cancer risk. The researchers calculated acrylamide intake from food frequency questionnaires completed by participants in the Nurses' Health Study II. Their findings were published in the American Journal of Epidemiology.

Studies That Have Found a Link

A Dutch study on 62,573 women aged 55-69 years found an association between acrylamide intake and increased risks of postmenopausal endometrial and ovarian cancer. The association was particularly strong in women who had never smoked. However, these findings did not apply to breast cancer risk, which was not associated with acrylamide intake. The researchers published their findings in Cancer Epidemiology Biomarkers & Prevention in 2007.

A prospective cohort study involving 88,672 women in the Nurses' Health Study found an increased risk of endometrial cancer among women who consumed the highest amounts of acrylamide. The researchers also observed a non-significant increased risk for ovarian cancer overall and a significant increased risk for serous tumors. However, they observed no association between breast cancer risk and acrylamide. Their findings were published in Cancer Epidemiology, Biomarkers & Prevention in 2010.

A 2008 study using blood acrylamide levels of postmenopausal women after adjusting for smoking status found a 2.7-fold increase in risk for estrogen receptor positive breast cancer for every 10-fold increase of acrylamide. The researchers analyzed blood samples of 374 breast cancer cases and 374 controls from a cohort of postmenopausal women. Their findings appeared in the International Journal of Cancer.

The Conclusion?

The bad news is, there is no clear-cut conclusion. The Food and Agriculture Organization (FAO) of the United Nations and the World Health Organization (WHO), along with other health institutions, continue to encourage scientists to carry out research on the carcinogenicity of acrylamide and to assess the overall health risks associated with acrylamide.

It is possible that the inconsistencies between the findings of various human studies are due to different levels of acrylamide, and that the findings that did show a link between acrylamide and cancer risk were simply based on higher levels of acrylamide. There is also evidence that certain food components, such as antioxidants in certain foods, may negate or mitigate the harmful effects of acrylamide.

If you are worried about the levels of acrylamide in your food, you may want to check out this list of foods that are high in acrylamide, and avoid eating the junk food included in the list. Note that the list also includes some foods that are known to offer health benefits (such as rye bread and prunes), and in many cases, the health benefits these foods offer are likely to outweigh any risks caused by their acrylamide content.

In addition to limiting your consumption of junk food that is rich in acrylamide, you can decrease your intake of this toxin by avoiding cooking food for too long or at too high a temperature. That said, it is important to cook food that may contain pathogens (such as raw meat) thoroughly in order to avoid other health complications.

Finally, if you are worried about the potential of acrylamide to cause cancer, keep in mind that cancer prevention is not only about what you don't eat, it's also about what you do put into your mouth. For more on that topic, check out our list of the best cancer-fighting foods.