Since at least August 2023, Facebook users have shared a warning about the purported dangers of McDonald's french fries containing "acrilane," which was described as "the most carcinogenic ingredient in cigarettes." That warning – which was shared both as copied-and-pasted text and in image form – also mentioned a pesticide that, when sprayed on potatoes grown for McDonald's, was supposedly so harmful that it required farmers to stay away for several days.
The most popular version of the rumor read as follows:
One large McDonald's french fry from McDonald's has the same amount of Acrilane as a pack of cigarettes. Acrilane is the most carcinogenic ingredient in cigarettes. McDonald's french fries are harvested from potatoes that are sprayed with a pesticide that is so harmful to humans that the farmers must let it sit for four days before they can safely handle it. Enjoy your fries!
We reached out to McDonald's via its media relations email address several times to ask about this matter but did not receive a response.
In our research, we found that the rumor was misleading in a number of different ways. This fact check explains why.
Acrylamide, Not 'Acrilane'
First off, as one Facebook user pointed out, "there is no such thing as 'acrilane.'" A Google search for the word "acrilane" with quotes around it mainly produced results for street names in the U.S.
The fact that whoever started this rumor misremembered and/or couldn't correctly spell the same of the purported "ingredient" did not bode well for the rest of our findings.
In our research, we found that the unknown user who originated this rumor was most likely referring not to "acrilane," but rather to acrylamide, as at least one user noted. Acrylamide forms as a byproduct of burning ingredients in cigarettes, but is not itself an “ingredient” in cigarettes. It is among many chemicals found in cigarette smoke classified as carcinogenic or potentially carcinogenic to humans.
Acrylamide Health Risks
Acrylamide is a substance that forms when an object, such as food or cigarettes, is heated up. For example, the longer that food is fried, roasted or baked, the higher the levels of acrylamide will be. As the FDA described on its website, the substance forms through a natural chemical reaction between sugars and asparagine, an amino acid, in plant-based foods – including potato and cereal-grain-based foods.
The FDA provided the following information about any associated health risks pertaining to acrylamide:
Acrylamide has been shown to cause cancer in animals exposed to very high doses, and although there is no consistent epidemiological evidence on the effect of acrylamide from food consumption on cancer in humans, both the U.S. National Toxicology Program and the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (JECFA) consider acrylamide to be a human health concern.
Acrylamide exposure can be detected by testing for the presence of acrylamide markers in the blood. According to scientists at the Centers for Disease Control and Prevention, markers of acrylamide exposure can be found in the blood of 99.9% of the U.S. population; however, finding these markers does not imply that their presence will result in adverse health effects.
As new research on the effect of acrylamide exposure becomes available, FDA experts will consider it in their continued evaluation of the risk that acrylamide may pose to human health.
Like the FDA, the European Union's European Food Safety Authority (EFSA) also published a page about acrylamide, notably saying that a 2015 risk assessment led experts to conclude that the substance "potentially increases the risk of developing cancer for consumers in all age groups," but that "studies on human subjects have provided limited and inconsistent evidence of increased risk of developing cancer."
Acrylamide Levels in Fries and Cigarettes
The Facebook rumor apparently intended to compare the amount of acrylamide in one large order of McDonald's french fries against the amount contained in an entire pack of cigarettes. We found past studies that attempted to measure acrylamide levels from the FDA, Annals of Agricultural and Environmental Medicine and Environmental Research.
The FDA's data from 2011 documented acrylamide levels in not just McDonald's french fries, but also similar levels of the substance in french fries from Burger King, Checkers, Chick-fil-A, KFC, Sonic, Wendy's and other restaurants. In other words, McDonald's was not a unique case in this regard. Rather, McDonald's was singled out by whoever started the viral rumor about acrylamide, when that person just as easily could have chosen to name any other restaurant.
Frequency of Consumption
To learn more about this subject, we consulted with Lindsey Wohlford, a wellness dietitian at The University of Texas MD Anderson Cancer Center. Wohlford told us during a Zoom call that it's "hard to compare" acrylamide levels in french fries and cigarettes, for a variety of different reasons.
"Generally, somebody who's going to be smoking is going to be doing that multiple times throughout the day, whereas somebody who is eating McDonald's french fries might be exposed to it once, perhaps twice," Wohlford said. "But, it's not something that's probably consumed as regularly as somebody who's smoking cigarettes."
A McDonald's Big Mac and french fries are seen on a tray on April 30, 2018 in Miami, Florida. (Photo by Joe Raedle/Getty Images)
One aspect of measuring acrylamide levels that should be noted is the fact that there are differences in the makeup of food products and in the times and methods of their preparation. For any researchers attempting to measure levels of the substance, these factors will provide varying results.
"Acrylamides in food products are very hard to measure because it depends on the innate amount of starch in an individual food at the time of cooking. There's variability," Wohlford said.
"Every single apple in the world doesn't have the 100% exact makeup. There's going to be some variability just depending on growing conditions, exposure to light and exposure to water. Nutrients in the soil. So, there's innately some differences in the nutritive content and makeup of foods. The other things, the other variable, is the cooking process. The method, the cooking time, the temperature and all of those things can impact the amount of acrylamide formed."
Entering the Bloodstream Differently
There's also the fact acrylamide enters the bloodstream in one way with food and in another way with cigarette smoke, as Wohlford told us.
"It's my understanding and knowledge that really there's quite a bit more [acrymalides] generally found when we do bloodwork with those people who smoke," she continued. "They tend to contain more acrylamides than people who are eating french fries, or McDonald's french fries."
"I think it's been fairly well-established that there are acrylamides that are from cigarette smoke. And that, in conjunction with obviously other aspects from smoking, are a risk for cancer. What we know with acrylamides from food, which are ingested in different ways, the cigarette smoke that's inhaled is going to go through the lungs and into the bloodstream, whereas food is going to be digested and potentially absorbed through our GI tract into the bloodstream."
Cancer Risk for Humans
Regarding the possible risk of cancer with the substance, Wohlford told us, "The vast majority of studies have been done on rodents, and they've been done in very large amounts, thousands of times what the average human is going to absorb from a food. And so, we really don't know the exact concerns we should have, or lack thereof, with acrylamides, as far as cancer risk, from any source — McDonald's french fries or any other source of acrylamides."
The FDA also published much the same, saying that, "Although it's not clear exactly what risk acrylamide poses to humans, the FDA has recommendations for both consumers and industry about how to reduce acrylamide formation in foods."
'Not Apples to Apples'
"On the internet, people take a grain of truth or a small piece of science out of context and they want to apply it to multiple situations or across the board," Wohlford said. "You can't really look at science in that way. It doesn't translate exactly that way. You have got to look at the circumstances surrounding the studies and the methods that were used.
"If they're not comparing apples to apples, you can't make any kind of a bottom line assumption."
Marianna Naum, an acting director with the FDA's Center for Food Safety and Applied Nutrition, who said she holds a doctoral degree, also told us in a separate call that the rumor circulating on Facebook was "not an accurate comparison," adding that with french fries and cigarettes, "there are different absorption pathways of how they would enter the body when something is ingested as opposed to when inhaled," a fact that Wohlford also previously noted.
The Big Picture
In our call with Wohlford, she told us that there's something missing from the Facebook rumor:
I think the bigger point here is that there are a lot of reasons to not eat french fries that are probably going to put you at bigger risk for chronic disease and health concerns more than acrylamides at this point. You're more likely to die of heart disease and other inflammatory conditions from eating french fries frequently than you are from exposure to cancer. So, we want to avoid french fries? Could it be because of the acrylamides contained in them? It could be. We really don't have the science to say that definitively yet. But we do have the science to say, hey, avoid this stuff because of other risks.
Also, weight gain. When people gain weight, overweight and obesity are associated with 13 different kinds of cancer. We know that french fries and many other highly processed, carbohydrate-rich foods, that also have acrylamides, are calorie-dense and can lead to increased weight gain, which puts people at risk for developing cancer.
Near the end of our call, Wohlford added, "To me, I think it's so interesting that people are even that concerned about this. I'm not saying they shouldn't be concerned, but to just be focused on this one component of McDonald's french fries, I think, if you're concerned about your health, why are you eating french fries at all? It's not so much this one component that may be in french fries in large amounts that we need to focus on."
Much of what Wohlford said was spelled out in a March 2022 article published on the MD Anderson Cancer Center website titled, "5 facts about acrylamide and cancer risk."
Pesticide Requires Farmers to Wait 4 Days?
The second half of the viral warning claimed that potatoes used by McDonald's are sprayed with a pesticide that's so harmful that farmers wait four days before handling them.
However, the truth was that the U.S. Environmental Protection Agency (EPA) includes in the compliance requirements for its Agricultural Worker Protection Standard (WPS) that, after pesticides have been applied to crops, a restricted-entry interval (REI) must be followed to keep workers safe. In other words, any such waiting period was not an unusual standard to have imposed when pesticides are used.
According to The Associated Press, the first substantial data published about acrylamide content in potatoes, cereal products and coffee came from scientists with the Swedish National Food Agency in the spring of 2002. At the time, the reporting cited new data from the FDA, saying in part that "the longer french fries and certain other starchy foods are fried or baked, the higher their level of a possible cancer-causing substance, new federal research suggests."
For further reading, Full Fact, Lead Stories and McGill's Office for Science and Society previously published reporting that provided the facts about a similar rumor that claimed McDonald's makes french fries from potatoes that were treated with a pesticide known as Monitor (methamidophos). Also, in 2021, the National Library of Medicine published new research about acrylamide and french fries, which included mentions of past guidance relevant to the substance brought forth by the state of California and the European Union.
We also looked into another substance, acrolein, for the purposes of this story. As an article from the National Library of Medicine noted, like acrylamide, acrolein is also present in cooked foods, including those fried in oil. Acrolein is a carcinogen and is present in the smoke of cigarettes. Due to the amount of past data regarding McDonald's french fries and acrylamide, most of which is spelled out in this article (including Prop 65 signs at McDonald's locations in California that mentioned acrylamide by name), it appeared that the person who created the viral rumor most likely was referencing past data about acrylamide, not acrolein.