On April 24, 2002, the Swedish National Food Administration (like our FDA) announced “alarmingly high” levels of acrylamide, a “known carcinogen,” in food. “If what we know from water and animal experiments is true, it could be a very significant cause of cancer in humans. It is not just another food scare.” Put down the chips and those large fries as we travel back to the “Great Potato Chip Scare.”
That quote was from the coordinator of the WHO’s food safety division, who, as it turns out, was perhaps a bit hyperbolic in his concerns. But those concerns echoed globally. In Sweden, where the announcement was made, chip sales dropped by nearly 50%. In California, it was the subject of some of the earliest and most persistent label warnings of Proposition 65; cases asking for acrylamide warnings on foods, including coffee, continue to kick around in federal courts. The latest case is still being adjudicated as of last October, 20 years later.
“Under Prop. 65, a “known” carcinogen carries a complex legal meaning that consumers would not glean from the warning without context. Thus, use of the word “known” is misleading—as the FDA acknowledged the warning might be. Even the State of California has stipulated that it “does not know that acrylamide causes cancer in humans …But acrylamide ‘must be listed [as known to the state to cause cancer] even [though] it is known to be carcinogenic only in animals.’ A reasonable person might think that they would consume a product that California knows will increase their risk for cancer. Such a consumer would be misled by the warning because the State of California does not know if acrylamide causes cancer in humans.”
- United States Court Of Appeals for The Ninth Circuit
The Swedish concern also prompted the first studies of acrylamide in food and the risk to humans.
Acrylamide is used in manufacturing and water treatment, hence EPA water treatment guidelines. The FDA regulates the amount of acrylamide in products that contact food, but there is no guidance as to acrylamide in our food. Why might that be?
Because it is not a food additive, it is a result of heating “vegetables that contain the amino acid asparagine, such as potatoes, are heated to high temperatures in the presence of certain sugars.” It is also found in tobacco smoke.
The two major sources of acrylamide are smoking and specific foods, like the reviled potato and its chip, crackers, bread, breakfast cereals, cookies, and coffee. All feature heating or roasting foods we are told daily are good for us, vegetables and grains. Smokers inhale far more acrylamide than they ingest. For the rest of us, the amounts of acrylamide we consume comes from what and how much we eat.
Studies of acrylamide in the workplace have shown an association between acrylamide exposure and neurologic changes, but not cancer in the workplace, but few of us work around acrylamide. The National Toxicology Program “considers acrylamide to be reasonably anticipated to be a human carcinogen, based on studies in laboratory animals given acrylamide in drinking water.” [emphasis added] But toxicology shows that rodents are not people when it comes to acrylamide absorption and metabolism. That puts rodent studies showing an association with cancer in doubt when they extrapolate those findings to humans.
“FFQs are a useful tool for assessing usual dietary pattern they were not designed for capturing chemical exposures.”
Many studies have demonstrated an association between acrylamide and the food we eat, and many others do not. Acrylamide and its cancer-associated metabolite, glycidamide, bind to hemoglobin and can be measured as HbAA and HbGA, just as we measure chronic glucose levels with HbA1c. Most studies involve food frequency questionnaires that capture our eating at one point and extrapolate that to months and years – a methodology full of uncertainty. Studies comparing food frequency surveys to actual HbAA and HbGA levels have shown a poor correlation. As a meta-analysis of acrylamide and cancer points out, in addition to these concerns, “for a given cooked food item, acrylamide levels can be influenced by free sugars and asparagine composition of the raw food, variations in cooking temperatures, varying lengths of cooking time, and different cooking methods used.”
A further entanglement is that the foods containing acrylamide have varying constituents and nutrients and provide high-energy foods – foods associated with obesity which is in turn associated with a heightened risk of cancer. So is it acrylamide, weight, both, or neither?
What’s a consumer to do?
Three generalities are offered
- Avoid carbohydrate-rich foods cooked at high temperatures
- Avoid overcooking foods
- Acrylamide is found in smaller amounts in “crisped” high-protein foods, like meat, but of course, for many, any amount of acrylamide is too great.
Manufacturers have taken steps to reduce the amount of asparagine, converting it enzymatically to aspartic acid that is not associated with cancer. The conversion enzyme comes from two forms of aspergillus, niger, and oryzae, which are particularly effective in reducing asparagine levels in doughs - used to form cereals and potato chip-like products (think Pringles).
In 2014, the USDA approved the first genetically modified potato to have reduced levels of asparagine, reducing the feared acrylamide, the Innate potato. (You may know it as the white russet) As with many GMO plants, it is not without its controversy. The chief scientist who developed the potato wrote a rebuke in his book Pandora’s Potato. Headlines suggested they were “no safer” than regular potatoes for carcinogenicity. But here is what he said,
“lowering the acrylamide levels in French fries is lowering the insignificantly-low levels of a carcinogen to even more insignificantly-low levels.”
The potato was created by J.R. Simplot, one of the biggest suppliers to the largest consumer of potatoes, McDonald’s. But McDonald’s is not using the potato, stating, "McDonald's USA does not source GMO potatoes, nor do we have current plans to change our sourcing practices,"
ACSH wrote a great deal on the topic; here are a few of the articles from the archives
For those looking for an excellent scientific overview, there is Acrylamide In Food: Is It A Real Threat To Public Health?, our original white paper on the topic
And a more timely report by the European Food Safety Authority, Scientific Opinion on acrylamide in food
Sources: Acrylamide and Cancer Risk National Cancer Institute
Acrylamide in foods Institute of Food Safety and Technology