Acrylamide is a widely used industrial chemical that is believed to be a human carcinogen. Workplace inhalation of large amounts of acrylamide causes neurological damage. Acrylamide is also a component of tobacco smoke, and it can form in some carbohydrate-rich foods when they are cooked at high temperature.
Acrylamide is a small organic (carbon-containing) molecule with the chemical formula C3H5NO. It is a colorless, odorless solid. The primary use of acrylamide is in the production of polyacrylamide polymers and acrylamide copolymers that contain additional molecular units. These polymers and copolymers are used in many industrial processes, including paper, dye, and plastic production; the manufacture of food packaging, caulking, and adhesives; and treatment of drinking water, wastewater, and sewage. Acrylamide and polyacrylamides are also used in the production of textiles, cosmetics, contact lenses, and organic chemicals; in ore processing and sugar refining; and as soil stabilizers and grout in various types of construction. Although acrylamide may enter drinking water during water treatment, it is not expected to accumulate in the environment, since it is rapidly broken down by bacteria in water and soil and is not usually found in the air. Nevertheless, acrylamide has been found in a few National Priority List Superfund sites designated by the U.S. Environmental Protection Agency (EPA).
It is unclear whether the amounts of acrylamide in foods increase the risk of human cancers. At very high doses, acrylamide causes various types of cancer in laboratory rats and mice of both sexes, indicating that it is a strong carcinogen. The International Agency for Research on Cancer, the U.S. Department of Health and Human Services, and the EPA classify acrylamide as a likely human carcinogen based on animal studies. In the human body, acrylamide is converted into glycidamide, which damages DNA and is classified as carcinogenic. High workplace inhalation of acrylamide causes neurological damage but has not been shown to increase cancer risk.
The major risk factors for acrylamide exposure in the general population are cigarette smoke and a wide range of carbohydrate-rich foods cooked at high temperatures. Blood markers of acrylamide exposure are three to five times higher in smokers compared to nonsmokers. Children have the most exposure to acrylamide in foods because of their lower body weight and their tendency to eat more of acrylamide-containing foods. Common acrylamide-containing foods include:
Other risk factors for acrylamide exposure include:
Acrylamide forms naturally when starchy foods containing sugars such as glucose or fructose and the amino acid asparagine are cooked or processed at everyday high temperatures over 248°F (120°C) with low moisture. Most acrylamide formation occurs as part of a chemical reaction called a Maillard reaction, which contributes to the browning, flavor, and aroma of cooked foods. Ingested acrylamide is absorbed through the gastrointestinal tract and distributed throughout the body, where it is extensively metabolized, especially to glycidamide. Glycidamide is believed to be responsible for the mutagenic and carcinogenic activities observed in animal studies.
Although the nervous system and the male reproductive system are the main targets of acrylamide toxicity, these are not thought to be at risk from dietary exposure. Some acrylamide workers have reported nervous system symptoms that include:
Acrylamide can cross the placenta of pregnant women and result in fetal exposure. Animals exposed to acrylamide during fetal development have decreased body weight, decreased startle responses, and lower levels of some brain neurotransmitters. Acrylamide has also been detected in human breast milk.
Acrylamide exposure can be diagnosed by measuring acrylamide and its metabolites in blood and urine.
Workplace accidents resulting in high-level acrylamide exposure require emergency procedures, including immediate removal from the source of acrylamide, decontamination and basic life-support measures.
In 2010, the Joint Food and Agriculture Organization/World Health Organization (FAO/WHO) Expert Committee on Food Additives labeled acrylamide a human health concern. The FAO and WHO maintain an international data-sharing network on acrylamide in foods, which is operated by the Joint Institute for Food Safety and Applied Nutrition, a collaboration between the U.S. Food and Drug Administration (FDA) and the University of Maryland.
In 2015, the European Food Safety Authority published a risk assessment, asserting that high levels of acrylamide in food could potentially increase the risk of all types of cancer in all age groups. In response, the United Kingdom's Food Standards Agency launched a Go for Gold campaign, advising consumers to aim for a golden yellow color or lighter when frying, baking, roasting, or toasting starchy foods such as potatoes, root vegetables, and breads. It also advised the pubic to follow cooking instructions carefully, to eat a balanced and varied diet, and not to store raw potatoes in the refrigerator, which causes the so-called cold sweetening that increases acrylamide levels.
The FDA regulates the amount of residual acrylamide in materials that contact food. As of 2018, the FDA did not regulate the amount of allowable acrylamide in food itself, although it was developing industry guidelines for reducing acrylamide levels in processed foods. Further studies by the National Toxicology Program were expected to inform the FDA's assessment of human risk from low-level acrylamide exposure and the need for measures to reduce food-related exposure. Additional studies on acrylamide formation during cooking are required, as well as a determination of whether acrylamide is present in any additional foods. Long-term epidemiologic studies are needed to assess any increased cancer risk from acrylamide in foods.
The EPA regulates acrylamide in drinking water. It has determined that concentrations of 1.5 mg/L for one day or 0.3 mg/L for ten days are not expected to adversely affect children.
The U.S. Occupational Safety and Health Administration limits workplace acrylamide exposure to 0.3 mg/m3 (1.3 yd.3) of air for an 8-hour workday and 40-hour workweek.
In 2018, a California judge ruled that Starbucks, Dunkin' Donuts, and dozens of other major national chains must warn consumers about potentially carcinogenic acrylamide formed during the roasting of coffee beans. California's Safe Drinking Water and Toxic Enforcement Act (Proposition 65) requires companies with more than ten employees to warn customers of the presence of any of almost 900 toxins, including acrylamide. The 2018 judge's ruling was in response to a lawsuit brought in 2010 by the Council for Education and Research on Toxics, a California nonprofit. Several of the original defendants, including 7-Eleven Stores, had previously settled out of court. However, many cancer experts argue that there is no evidence for increased cancer risk from drinking coffee, which contains at least 1,500 other compounds, and that coffee is an antioxidant that may actually reduce the risk of some types of cancer. In 2016, WHO rescinded its earlier designation of possible carcinogenic effects from drinking coffee.
Methods for preventing or reducing acrylamide exposure include:
See also Cancer ; smoking .
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Agency for Toxic Substances and Disease Registry, Division of Toxicology and Human Health Sciences, 1600 Clifton Rd. NE, Mailstop F-57, Atlanta, GA, 30333, (800) 232-4636, https://www.atsdr.cdc.gov .
Environmental Protection Agency, 1200 Pennsylvania Ave. NW, Washington, DC, 20460, https://www.epa.gov .
European Food Safety Authority, Via Carlo Magno 1A, Parma, Italy, 43126, +390521 036111, Fax: +390521 036110, http://www.efsa.europa.eu/en .
International Agency for Research on Cancer, 150 Cours Albert Thomas, 69372 Lyon, France, CEDEX 08, 33 (0)4 72 73 84 85, http://www.iarc.fr .
National Cancer Institute, BG 9609, MSC 9760, 9609 Medical Center Dr., Bethesda, MD, 20892-9760, (800) 422-6237, https://www.cancer.gov .
National Institute of Environmental Health Sciences, PO Box 12233, MD K3-16, Research Triangle Park, NC, 27709-2233, (919) 541-3345, Fax: (301) 480-2978, firstname.lastname@example.org, https://www.niehs.nih.gov .
U.S. Food and Drug Administration, 10903 New Hampshire Ave., Silver Spring, MD, 20993, (888) 463-6332, https://www.fda.gov .
World Health Organization, Avenue Appia 20, 1211 Geneva, Switzerland, 27, 41 22 791 21 11, Fax: 41 22 791 31 11, http://www.who.int/en .
Margaret Alic, PhD