Does Microwave Popcorn Cause Cancer?

According to several scientific studies, flavoring additives like diacetyl and other chemicals used in microwave popcorn bags were deemed unsafe because of the potential risk of health effects, such as irreversible lung damage.

As a result, between 2002 and 2015, diacetyl and other substances were eventually phased out from microwave popcorn and its packaging. Still, consumers should be aware that some chemicals continue to be in use.

Chemicals in Microwave Popcorn

If you’re avoiding unhealthy snacks by reaching for low-fat and low sodium treats like microwave popcorn, you may want to take into consideration the chemicals used to coat its packaging. According to the Environmental Protection Agency (EPA), these chemicals might include perfluoroalkyl and polyfluoroalkyl substances (PFAS).

They may include a subset of PFAS like PFOA or C8, PFOS, GenX, and other chemicals found in common nonstick household products and in fast food packaging (pizza, burgers, fries, and microwave popcorn bags).

A 2020 report examined microwave popcorn packaging and 407 samples of paper, including paperboard food wrappers used by fast-food chains coated with five common PFAS (PFOA, PFOS, perfluorononanoic acid, perfluorodecanoic acid, and perfluorohexanesulfonic acid).

They found the coated PFAS paper products increased the PFAS blood serum levels of people who habitually consumed microwave popcorn and restaurant fast food versus cooked meals prepared from grocery store products.

The data showed 90% of the food purchased from the grocery store was less likely to be tainted by PFAS from packaging, in contrast to the wrapped or boxed fast food. This led to higher concentrations of PFAS in the blood serum of fast-food consumers and those who snacked on microwave popcorn, as compared with those who cooked their meals.

 A 2017 study identified 46 different PFASs found in microwave popcorn bags manufactured in 12 European (Spain, France, Austria, The Netherlands, Hungary, Germany, Italy, Ireland, Czech Republic, Sweden, United Kingdom, Portugal), three American (Mexico, Brazil, and the U.S.), and two Asian countries (China and India) from 2015 to 2016.

The EPA reports that several PFAS have been phased out and are no longer produced in the United States. However, they are still manufactured in other countries and continue to appear in a number of consumer products that are imported into the United States.

What Is Popcorn Lung?

Bronchiolitis obliterans (popcorn lung) is a condition of scarred air sacs in the lungs that thicken and narrow the air passageways. It causes a number of symptoms (coughing, wheezing, and shortness of breath) that are similar to symptoms of chronic obstructive pulmonary disease (COPD). Popcorn lung is a rare, chronic disease that becomes worse over time, eventually leading to respiratory failure. 

Popcorn lung was brought to the public’s attention in 2000 when public health authorities learned of workers at a Missouri microwave popcorn facility who had inhaled excessive and concentrated amounts of diacetyl—a butter flavoring—and were later diagnosed with irreversible lung disease.

A 2012 study provides three case studies of exposure to diacetyl through consuming several daily portions of microwave popcorn. Researchers from the National Institute for Occupational Safety (NIOSH) discovered that long-term exposure of diacetyl had a direct relationship with reduced lung capacity.

Diacetyl

Recognized for both its buttery aroma and flavoring, diacetyl is a natural compound found in foods such as butter, yogurt, a variety of cheeses, and sour cream. It is also added to numerous foods, including microwave popcorn.

In a 2015 report, the U.S. Food and Drug Administration deemed diacetyl to be “generally recognized as safe (GRAS)” as shown by centuries of human exposure to its natural presence in foods without any dire health consequences. However, in animal toxicology studies, heated butter flavoring damaged cells that line the airways of mice.

In the case of workers at microwave popcorn facilities across the Midwest, NIOSH studies found that mixers who worked with diacetyl and heated soybean oil for more than a year were exposed to higher levels of diacetyl fumes and experienced more shortness of breath than workers employed for less than 12 months or who worked elsewhere in the plant.

Perfluorinated Compounds (PFCs)

Similar to PFAS, perfluorinated compounds such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA or C8) are used in several consumer products including water-proof textiles, nonstick cookware, lubricants, grease and water-proof coating for food packing, and microwave popcorn bags. And like PFAS, these chemicals exist in the environment and appear in blood samples in humans.

Research studies using PFOA on rats resulted in liver, testicular, and pancreatic cancers, but studies in humans have not been statistically significant. However, a link appeared between PFOA blood serum levels and kidney cancer and testicular cancer in chemical plant workers where PFOA was produced, and also in persons who lived near the facility.

In 2001, residents within living distance of the plant filed a class-action lawsuit, suing the company for groundwater contamination. The court-appointed three epidemiologists to study whether PFOA had any role in contributing to health issues. They concluded that PFOA most likely had played a role in contributing to health problems.

From 2011 to 2012, four reports were presented to the court that PFOA had possibly been the cause of six cases of kidney cancer, testicular cancer, ulcerative colitis, thyroid disease, hypercholesterolemia, and pregnancy-induced hypertension.

By 2002, PFOS was phased out both in production and use. Manufacturers in the United States terminated PFOA emissions and content in products by the end of 2015. Despite the phasing out and cessation in the U.S. and Europe, it is unclear whether production has moved to Asia.

A 2019 study analyzed seven popcorn corn bags for PFOA and PFOS concentrations and compared them to concentrations found between 2005 and 2018. Researchers found two of the microwave popcorn bags were above the accepted limit, while the remaining five were below the limit of detection.

A Word From Verywell

Due to the removal of diacetyl and other chemicals, microwave popcorn no longer appears to be damaging to your health. Nevertheless, consumers should be aware that some substances are still used in the packaging.

In addition, many of the ingredients used (emulsifiers, trans fats, and artificial flavoring) are not optimal for nutrition or health. If popcorn is your snack of choice, follow the guidelines of the American Heart Association to make your own healthy version.