Why does acrylamide form in cigarettes and french fries and should I care?

Image: “Acrylamide” by trendingtopics is licensed under CC BY 2.0

Sometimes I wonder if food scares exist to keep research scientists and newspaper tabloids in business. So here’s the deal on acrylamide, one of the many food scares that repeats on a regular cycle.

In April 2002, the Swedish National Food Authority reported the presence of elevated levels of a chemical called acrylamide in certain types of food processed at high temperatures. Since then, acrylamide has been found in a range of cooked and heat-processed foods in other countries, including The Netherlands, Norway, Switzerland, the United Kingdom and the United States.

Acrylamide is known to cause cancer in animals. Also, certain doses of acrylamide are toxic to the nervous system of both animals and humans.  Previous concerns about acrylamide were focused on workers using acrylamide in their jobs and cigarette smoking.

 There is currently little information about, and poor understanding of, how acrylamide is formed in foods. It appears to be produced naturally in some foods that have been cooked or processed at high temperature and the levels of acrylamide appear to increase with the duration of heating. The highest levels found so far were in starchy foods (potato and cereal products).  Further research is needed to explain why acrylamide forms in food as well as the conditions that promote or reduce its presence in food.

To avoid acrylamide, food should not be cooked too long or at too high a temperature.  Acrylamide has so far not been found in food prepared at temperatures below 248 degrees Fahrenheit, or 120 degrees Celsius, including boiled foods.  However, all food, especially meat and meat products, should be cooked sufficiently to destroy food poisoning bacteria.

Elevated levels of acrylamide have been found in home cooked foods, as well as pre-cooked, packaged and processed foods.

Let’s dig a bit deeper

What is acrylamide? 

Scientific answer: 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.

Squirrel answer: It’s formed when certain substances, usually plant-based, are heated above a certain temperature. 

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. Potato chips and French fries were found to contain higher levels of acrylamide compared with other foods.

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. We’re not quite sure why it’s a major concern as most of the human studies published so far have failed to find any links between dietary acrylamide and various types of cancers.

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, 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.

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.

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. 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.

Are there other ways humans are exposed to acrylamide? 

Food and cigarette smoke are the major sources of acrylamide exposure. 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. 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.

A series of case-control studies has 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.

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.

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.

Should I be bothered?
No. If you’re living on french fries in a smoky environment you have bigger issues to worry about.

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.