Claims that McDonald’s french fries contain a chemical found in cigarette smoke need context

In November 2023, a viral TikTok video with over 613,000 likes claimed acrylamide, a toxic substance found in cigarette smoke, can also be found in McDonald’s french fries. Similar claims were shared widely in a meme on Facebook, although acrylamide was misspelled in most of these posts.

In addition to the acrylamide claims, the meme also suggests that McDonald’s french fries are made from potatoes that are sprayed with a pesticide that is so harmful to humans farmers must let it sit for four days before they can safely handle it.

VERIFY reader Ruth asked us in an email if there is any truth to these claims.

THE QUESTION

Do McDonald's french fries contain acrylamide, a chemical also found in cigarette smoke?

THE SOURCES

• McDonald’s
• U.S. Food and Drug Administration (FDA)
• U.S. Centers for Disease Control and Prevention (CDC) 
• National Cancer Institute 
• American Cancer Society
• U.S. National Toxicology Program’s Report on Carcinogens
• The University of Texas MD Anderson Cancer Center article
• City of Hope, cancer treatment and research centers
• Article by Joe Schwarcz, Ph.D., director of McGill University’s Office for Science and Society 
• Article published in Environmental Research, a multi-disciplinary journal of environmental sciences and engineering 
• Article published in Foods, an international, peer-reviewed, open-access journal on food science
• Author manuscript published in Nutrition and Cancer, a peer-reviewed medical journal covering research on the role of nutritional factors in causing or preventing cancer
• Research paper published in the Annals of Agricultural and Environmental Medicine (AAEM)
• Kendall Stelwagen, clinical nutrition specialist at the University of Texas MD Anderson Cancer Center

THE ANSWER

Acrylamide naturally forms when some foods, including french fries, are cooked at very high temperatures, for example during frying, roasting or baking. It’s also found in cigarette smoke.

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WHAT WE FOUND

Acrylamide is not an additive or ingredient found on a label, City of Hope says. Instead, it is a chemical that naturally forms when certain foods, including french fries, are prepared using high-temperature cooking processes, such as frying, roasting or baking, according to the U.S. Food and Drug Administration (FDA).

Acrylamide is also a component found in cigarette smoke, but our sources say there is more acrylamide in tobacco smoke than in food. It’s unclear at this time exactly what risk acrylamide poses to humans, but the FDA says the chemical caused cancer in animals that were exposed to acrylamide at very high doses.

VERIFY also found the potatoes McDonald’s uses to make its french fries are not grown using a highly toxic pesticide that farmers must let sit for four days before handling.

Acrylamide in foods

The FDA says acrylamide was first detected in foods in 2002. However, the agency notes the chemical has “probably always been present in cooked foods.” Studies have not shown a health impact on humans from eating foods with acrylamide.

Acrylamide forms through a natural chemical reaction between sugars and asparagine, an amino acid, when plant-based foods, like potatoes and cereal-grain-based foods, are cooked at high heat. Acrylamide is found in french fries, crackers, bread, cookies, breakfast cereals, canned black olives, prune juice and coffee, according to the National Cancer Institute.

“Acrylamide forms when foods like potatoes and cereals become crispy and brown. It even forms in roasted coffee beans,” said Kendall Stelwagen, a clinical nutrition specialist at the University of Texas MD Anderson Cancer Center.

This means french fries from any restaurant, including McDonald’s, or potatoes purchased at the grocery store that are fried, roasted or baked at high temperatures at home, likely contain acrylamide. The National Cancer Institute says acrylamide levels in food vary widely depending on the manufacturer, the cooking time and the method and temperature of the cooking process.

Stelwagen agrees.

“It’s very difficult to measure the amount of acrylamide in foods because there is so much variation in food production and even in the foods themselves,” she said. “From one potato to another, the amount of acrylamide that forms in cooking can be very different. And the cooking processes can be different, too.”

In the United States, the FDA regulates the amount of residual acrylamide in certain products that have contact with food, and the U.S. Environmental Protection Agency (EPA) monitors and regulates acrylamide in drinking water. But acrylamide in food is not monitored or regulated by any federal agency, the National Cancer Institute and the MD Anderson Cancer Center both say.

However, in 2016, the FDA issued guidance to help the food industry reduce the amount of acrylamide in certain foods. The agency says it does not identify any specific maximum recommended level or action level for acrylamide in foods.

Between 2011 and 2015, the FDA collected approximately 2,500 individual food product samples to study acrylamide levels in foods. The agency’s most recent survey data on acrylamide in food from 2015 found that french fries from various brands contain an average of 337 micrograms per kilogram (μg/kg) of the chemical, according to an experimental review of acrylamide in french fries published by researchers at Boise State University in 2021.

Acrylamide is considered a probable human carcinogen by the EPA. However, the only studies that show a clear link between acrylamide and cancer tested animals and involved very high levels of the chemical, according to the FDA and the MD Anderson Cancer Center.

The U.S. National Toxicology Program’s report on carcinogens, for example, said acrylamide exposure in two rodent species, via drinking water and injection at several different tissue sites, caused cancerous tumors in rats of both sexes. But the National Cancer Institute says other studies that followed people over time did not find a link between eating foods with acrylamide and cancer.

If you’re worried about the amount of acrylamide in your french fries and other foods, there are ways you can reduce your exposure. Stelwagen suggests cooking food for less time to reduce the amount of crisping and browning, lightly boiling potatoes before cooking and avoiding storing potatoes in the fridge because doing so can make them crispier.

“Food manufacturers have tried to reduce acrylamide in some foods, but it usually results in loss of quality,” said Stelwagen. “The browning reaction is what gives food the nice tasty flavor and the appearance that we like, so I recommend eating the food as is in moderation, as a small part of a healthy diet.”

The FDA also recommends that people concerned about acrylamide in their food adopt a healthy eating plan that emphasizes fruits, vegetables, whole grains, and fat-free or low-fat milk and milk products, as well as lean meats, poultry, fish, beans, eggs and nuts.

Acrylamide in cigarette smoke and other products

In addition to occurring in certain foods, acrylamide is also a component of cigarette or tobacco smoke, according to our sources. The chemical typically forms when tobacco is heated.

The National Cancer Institute says people are exposed to substantially more acrylamide when inhaling cigarette or tobacco smoke than from food. Researchers have found that smokers have around three to five times more acrylamide in their blood than non-smokers.

City of Hope says more research is needed to understand whether there’s a link between acrylamide and cancer in humans. The cancer treatment center and Stewalgen recommend avoiding cigarette smoke altogether to lower the exposure to acrylamide.

“If you smoke, quit as soon as you can. If you don’t smoke, avoid secondhand and thirdhand smoke so you escape the toxins it contains,” Stelwagen said.

Many industries use acrylamide to make paper, dyes and plastics, and to treat drinking water and wastewater. The chemical is also found in some household products, such as caulking, food packaging, some adhesives and cosmetics.

The U.S. Centers for Disease Control and Prevention (CDC) says the human health effects from environmental exposure to low levels of acrylamide are currently unknown. But the agency says inhaling large amounts of acrylamide can irritate breathing passages and can cause nerve damage after long-term exposure.

Debunking claims about McDonald’s french fries and pesticides

In 2014, author Michael Pollan claimed that McDonald’s used a type of potato known as Russet Burbank to make its french fries. At the time, Pollan suggested that the fast food company forced farmers to treat the potatoes with a highly toxic pesticide called methamidophos or Monitor to get rid of blemishes caused by aphids.

Pollan also alleged that the pesticide “is so toxic that farmers who grow these potatoes in Idaho won’t venture outside into their fields for five days after they spray.”

On its website, McDonald’s says it uses several types of potatoes, including Russet Burbank, Ranger Russet, Umatilla Russet and the Shepody, to make its french fries. The company debunked Pollan’s pesticide claims online in 2018.

“Our suppliers do not use pesticides containing methamidophos,” McDonald’s said. The chemical was banned for use as a pesticide in the U.S. in 2009. Methamidophos is also banned in Europe.

Joe Schwarcz, Ph.D., the director of McGill University’s Office for Science and Society, called Pollan’s claims “unnecessarily alarmist” and “pure nonsense” in a 2017 article. Other fact-checking organizations, including Politifact, have also debunked Pollan’s claims.

VERIFY reached out to McDonald’s for a response but did not hear back by the time of publication.

This story is also available in Spanish / Lee este artículo también en español: Afirmaciones diciendo que las papas fritas de McDonald's contienen un químico encontrado en humo de cigarrillo necesitan contexto