Acrylamide

Acrylamide (C3H3ONH2) is a chemical that is produced naturally in certain foods when they are cooked at high temperatures. It is also manufactured industrially for use in the production of polyacrylamide gels, which are used for various purposes, including the treatment of drinking-water and wastewater. Acrylamide is known to cause cancer in animals and, in high doses, can cause nerve damage in humans.

What is acrylamide?

Acrylamide is a chemical used primarily as a building block in making polyacrylamide and acrylamide copolymers. Polyacrylamide and acrylamide copolymers are used in many industrial processes, such as the production of paper, dyes, and plastics, and in the treatment of drinking water and wastewater, including sewage. They are also found in consumer products, such as caulking, food packaging, and some adhesives. Trace amounts of acrylamide generally remain in these products.

Is there acrylamide in food?

Researchers in Europe and the United States have found acrylamide in certain foods that were heated to a temperature above 120 degrees Celsius (248 degrees Fahrenheit), but not in foods prepared below this temperature (1). Potato chips and French fries were found to contain higher levels of acrylamide compared with other foods (2). The World Health Organization and the Food and Agriculture Organization of the United Nations stated that the levels of acrylamide in foods pose a “major concern” and that more research is needed to determine the risk of dietary acrylamide exposure (2).

How does cooking produce acrylamide?

Asparagine is an amino acid (a building block of proteins) that is found in many vegetables, with higher concentrations in some varieties of potatoes. When heated to high temperatures in the presence of certain sugars, asparagine can form acrylamide. High-temperature cooking methods, such as frying, baking, or broiling, have been found to produce acrylamide (3), while boiling and microwaving appear less likely to do so. Longer cooking times can also increase acrylamide production when the cooking temperature is above 120 degrees Celsius (4, 5).

Is there anything in the cooking process that can be changed to lower dietary acrylamide exposure?

Decreasing cooking time, blanching potatoes before frying, and postdrying (drying in a hot air oven after frying) have been shown to decrease the acrylamide content of some foods (6, 7).

Should I change my diet?

Acrylamide levels in food vary widely depending on the manufacturer, the cooking time, and the method and temperature of the cooking process (8, 9). The best advice at this time is to follow established dietary guidelines and eat a healthy, balanced diet that is low in fat and rich in high-fiber grains, fruits, and vegetables.

Food storage and preparation methods

 

• Comparing frying, roasting, and baking potatoes, frying causes the highest acrylamide formation. Roasting potato pieces causes less acrylamide formation, followed by baking whole potatoes. Boiling potatoes and microwaving whole potatoes with skin on to make “microwaved baked potatoes” does not produce acrylamide.¹
• Soaking raw potato slices in water for 15-30 minutes before frying or roasting helps reduce acrylamide formation during cooking. (Soaked potatoes should be drained and blotted dry before cooking to prevent splattering or fires.)
• Storing potatoes in the refrigerator can result in increased acrylamide during cooking. Therefore, store potatoes outside the refrigerator, preferably in a dark, cool place, such as a closet or a pantry, to prevent sprouting.
• Generally, more acrylamide accumulates when cooking is done for longer periods or at higher temperatures. Cooking cut potato products, such as frozen French fries or potato slices, to a golden yellow color rather than a brown color helps reduce acrylamide formation (see Picture A). Brown areas tend to contain more acrylamide.
• Toasting bread to a light brown color, rather than a dark brown color, lowers the amount of acrylamide (see Picture B). Very brown areas should be avoided, since they contain the most acrylamide.
• Acrylamide forms in coffee when coffee beans are roasted, not when coffee is brewed at home or in a restaurant. So far, scientists have not found good ways to reduce acrylamide formation in coffee.

 

 

Are there other ways humans are exposed to acrylamide?

Food and cigarette smoke are the major sources of acrylamide exposure (10). Exposure to acrylamide from other sources is likely to be significantly less than that from food or smoking, but scientists do not yet have a complete understanding of all sources of exposure. Acrylamide and polyacrylamide are used in some industrial and agricultural procedures, and regulations are in place to limit exposure in those settings.

Does acrylamide increase the risk of cancer?

 

Studies in rodent models have found that acrylamide exposure poses a risk for several types of cancer (11, 12, 13). However, the evidence from human studies is still incomplete. The National Toxicology Program and the International Agency for Research on Cancer consider acrylamide to be a “probable human carcinogen,” based on studies in laboratory animals given acrylamide in drinking water. However, toxicology studies have shown differences in acrylamide absorption rates between humans and rodents (14).

A series of case-control studies have investigated the relationship between dietary intake of acrylamide and the risk of developing cancers of the oral cavity, pharynx, esophagus, larynx, large bowel, kidney, breast, and ovary. These studies generally found no excess of tumors associated with acrylamide intake (15, 16, 17, 18, 19). In the studies, however, not all acrylamide-containing foods were included in estimating exposures. In addition, information in case-control studies about exposures is often based on interviews (personal or through questionnaires) with the case and control subjects, and these groups may differ in the accuracy of their recall about exposures. One factor that might influence recall accuracy in cancer-related dietary studies is that diets are often altered after receiving a diagnosis of cancer.

To avoid such limitations in accurately determining acrylamide exposure, biomarkers of exposure were recently used in a Danish cohort study designed to evaluate the subsequent risk of breast cancer in postmenopausal women (20). Among women with higher levels of acrylamide bound to the hemoglobin in their blood, there was a statistically significant increase in risk of estrogen receptor-positive breast cancer. This finding suggests an endocrine hormone-related effect, which would be consistent with the results of a questionnaire-based cohort study in the Netherlands that found an excess of endometrial and ovarian cancer—but not of postmenopausal breast cancer—associated with higher levels of acrylamide exposure (21). Another cohort study from the Netherlands suggested a positive association between dietary acrylamide and the risk of renal cell cancer, but not of prostate or bladder cancer (22).

What are other health effects of acrylamide?

High levels of acrylamide in the workplace have been shown to cause neurological damage, e.g., among workers using acrylamide polymers to clarify water in coal preparation plants (23).

Are acrylamide levels regulated?

The U.S. Environmental Protection Agency (EPA) regulates acrylamide in drinking water. The EPA established an acceptable level of acrylamide exposure, set low enough to account for any uncertainty in the data relating acrylamide to cancer and neurotoxic effects. The U.S. Food and Drug Administration regulates the amount of residual acrylamide in a variety of materials that come in contact with food, but there are currently no guidelines governing the presence of acrylamide in food itself.

 

What research is needed?

Although studies in rodent models suggest that acrylamide is a potential carcinogen, additional epidemiological cohort studies are needed to help determine any effects of dietary acrylamide intake on human cancer risk. It is also important to determine how acrylamide is formed during the cooking process and whether acrylamide is present in foods other than those already tested. This information will enable more accurate and comprehensive estimates of dietary exposure. Biospecimen collections in cohort studies will provide an opportunity to avoid the limitations of interview-based dietary assessments by examining biomarkers of exposure to acrylamide and its metabolites in relation to the subsequent risk of cancer.
For information about acrylamide from the World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations, please visit WHO’s Food Safety: Acrylamide page.
For information about acrylamide from the National Toxicology Program (NTP), please visit NTP's Report on Carcinogens.

Selected References

1. Stadler RH, Blank I, Varga N, et al. Acrylamide from Maillard reaction products. Nature 2002; 419(6906):449–450.
2. Food and Agriculture Organization of the United Nations. World Health Organization. Summary report of the sixty-fourth meeting of the Joint FAO/WHO Expert Committee on Food Additives (JECFA). Retrieved July 24, 2008, from: http://www.who.int/entity/ipcs/food/jecfa/summaries/summary_report_64_final.pdf .
3. Mottram DS, Wedzicha BL, Dodson AT. Acrylamide is formed in the Maillard reaction. Nature 2002; 419(6906):448–449.
4. Gertz C, Klostermann S. Analysis of acrylamide and mechanisms of its formation in deep-fried products. European Journal of Lipid Science and Technology 2002; 104(11):762–771.
5. Rydberg P, Eriksson S, Tareke E, et al. Investigations of factors that influence the acrylamide content of heated foodstuffs. Journal of Agricultural and Food Chemistry 2003; 51(24):7012–7018.
6. Kita A, Brathen E, Knutsen SH, Wicklund T. Effective ways of decreasing acrylamide content in potato crisps during processing. Journal of Agricultural and Food Chemistry 2004; 52(23):7011–7016.
7. Skog K, Viklund G, Olsson K, Sjoholm I. Acrylamide in home-prepared roasted potatoes. Molecular Nutrition and Food Research 2008; 52(3):307–312.
8. Tareke E, Rydberg P, Karlsson P, Eriksson S, Tornqvist M. Analysis of acrylamide, a carcinogen formed in heated foodstuffs. Journal of Agricultural and Food Chemistry 2002; 50(17):4998–5006.
9. Mojska H, Gielecinska I, Szponar L. Acrylamide content in heat-treated carbohydrate-rich foods in Poland. Roczniki Panstwowego Zakladu Higieny 2007; 58(1):345–349.
10. Urban M, Kavvadias D, Riedel K, Scherer G, Tricker AR. Urinary mercapturic acids and a hemoglobin adduct for the dosimetry of acrylamide exposure in smokers and nonsmokers. Inhalation Toxicology 2006; 18(10):831–839.
11. Dearfield KL, Abernathy CO, Ottley MS, Brantner JH, Hayes PF. Acrylamide: Its metabolism, developmental and reproductive effects, genotoxicity, and carcinogenicity. Mutation Research 1988; 195(1):45–77.
12. Dearfield KL, Douglas GR, Ehling UH, et al. Acrylamide: A review of its genotoxicity and an assessment of heritable genetic risk. Mutation Research 1995; 330(1–2):71–99.
13. Friedman M. Chemistry, biochemistry, and safety of acrylamide. A review. Journal of Agricultural and Food Chemistry 2003; 51(16):4504–4526.
14. Fuhr U, Boettcher MI, Kinzig-Schippers M, et al. Toxicokinetics of acrylamide in humans after ingestion of a defined dose in a test meal to improve risk assessment for acrylamide carcinogenicity. Cancer Epidemiology Biomarkers and Prevention 2006; 15(2):266–271.
15. Pelucchi C, Galeone C, Levi F, et al. Dietary acrylamide and human cancer. International Journal of Cancer 2006; 118(2):467–471.
16. Mucci LA, Dickman PW, Steineck G, Adami HO, Augustsson K. Dietary acrylamide and cancer of the large bowel, kidney, and bladder: Absence of an association in a population-based study in Sweden. British Journal of Cancer 2003; 88(1):84–89.
17. Mucci LA, Lindblad P, Steineck G, Adami HO. Dietary acrylamide and risk of renal cell cancer. International Journal of Cancer 2004; 109(5):774–776.
18. Mucci LA, Adami HO, Wolk A. Prospective study of dietary acrylamide and risk of colorectal cancer among women. International Journal of Cancer 2006; 118(1):169–173.
19. Mucci LA, Sandin S, Balter K, et al. Acrylamide intake and breast cancer risk in Swedish women. Journal of the American Medical Association 2005; 293(11):1326–1327.
20. Olesen PT, Olsen A, Frandsen H, et al. Acrylamide exposure and incidence of breast cancer among postmenopausal women in the Danish Diet, Cancer and Health Study. International Journal of Cancer 2008; 122(9):2094–2100.
21. Hogervorst JG, Schouten LJ, Konings EJ, Goldbohm RA, van den Brandt PA. A prospective study of dietary acrylamide intake and the risk of endometrial, ovarian, and breast cancer. Cancer Epidemiology Biomarkers and Prevention 2007; 16(11):2304–2313.
22. Hogervorst JG, Schouten LJ, Konings EJ, Goldbohm RA, van den Brandt PA. Dietary acrylamide intake and the risk of renal cell, bladder, and prostate cancer. American Journal of Clinical Nutrition 2008; 87(5):1428–1438.
23. Mulloy KB. Two case reports of neurological disease in coal mine preparation plant workers. American Journal of Industrial Medicine 1996; 30(1):56–61.

 

Sources: WHO /  National Cancer Institute / FDA