Non-stick chemicals have been used in food packaging since the 1960s, but new research reveals just how much of these mysterious, possibly dangerous, “forever chemicals” have seeped in your fast food.

Called per- and polyfluoroalkyl substances, or PFAS for short, nearly 5,000 types exist, but scientists don’t quite understand the extent to which they pose a health threat.

What is known is that man-made PFAS are everywhere, including in soil, water, air, and our blood. Because PFAS contain the elemental bonds of fluorine and carbon, it can take thousands of years for them to degrade, which is why when PFA-containing trash gets thrown into a landfill, the chemicals can migrate into dirt and groundwater.

Researchers from the Silent Spring Institute and the University of Massachusetts Amherst examined how eating food made at home, compared to food prepared at a restaurant, affects the likelihood of PFAS exposure. They shared their findings Wednesday in a study published in the journal Environmental Health Perspectives.

They found that people who had higher levels of PFAS in their bodies were those who tended to eat more fast food or more frequently at restaurants. It’s hypothesized that this is because that category of food has greater contact with food packaging, which can contain PFAS. The study posits that PFAS chemicals migrate from food packaging, into food, then into our bodies.

"The less contact your food has with food packaging, the lower your exposures to PFAS

Study co-author Kathryn Rogers, a staff scientist at the Silent Spring Institute, says she hopes safer food packaging is on the horizon.

“The general conclusion here is the less contact your food has with food packaging, the lower your exposures to PFAS and other harmful chemicals,” , explains.

“These latest findings will hopefully help consumers avoid these exposures and spur manufacturers to develop safer food packaging materials.”

So is this enough to make you stop ordering fast food that comes in PFAS-coated packaging? Probably not, but what we don’t know about PFAS is worth considering: According to a CDC overview, it’s difficult to show that PFAS directly cause health problems, but the few scientific studies on the matter indicate that PFAS exposure can come at a cost. Studies on humans indicate certain PFAS can cause issues including interfering with the body’s natural hormones, increasing the risk of cancer, and affecting the immune system.

Previously, scientists found fast food packaging can contain PFAS. Unsplash / Christopher Flowers

How researchers came to their conclusion

Rogers and her colleagues analyzed data from 10,106 people who were part of the National Health and Nutrition Examination Survey (NHANES), a Centers for Disease Control and Prevention program that tracks health and nutritional trend via a combination of interviews, physical examinations, and bio-monitoring.

This survey data stemmed from six surveys that occurred between 2003 and 2014, and involved what people could remember eating over four timescales: The past 24-hours, seven days, 30 days, and 12-months. In turn, the participant’s blood samples were analyzed for five different PFAS: perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorohexanesulfonic acid (PFHxS), and perfluorooctanesulfonic acid (PFOS).

In turn, the team determined that the people who ate more meals at home had significantly lower levels of PFAS in their bodies. Meanwhile, the consumption of food from fast food (including pizza) places and restaurants was, per the study, “generally associated with higher serum PFAS concentrations.” The scientists write:

“We hypothesize that these associations may be related to the extent of contact that these foods have with food packaging, although we cannot rule out the possibility that differences in the types of food consumed in various locations may also contribute to these associations.”

Significantly higher levels of PFOA, PFNA, PFDA, and PFOS were also linked to eating popcorn at home, which the researchers note may be a consequence of PFAS migration from microwave popcorn bags into the food.

Popcorn bags are also linked to PFAS. Unsplash / Andres Aleman

Importantly, the team writes that a potential limitation of this study is that the questionnaire only includes results for long-chain PFAS because those are the most frequently detected. In the United States, manufacturers are slowly replacing these types of PFAS with new varieties because of concerns about the bioaccumulation and toxicity of the others. Long-chain PFAS can live on in the body for years, so it’s likely that their presence can be detected in blood, even if actual chemical has been disbanded.

The FDA says that the level of PFAS the agency has found in food are not at a level that constitutes a food safety risk. That’s regardless of finding on-the-shelf chocolate cakes with PFAS levels 250 times higher the federal guidelines.

Accordingly, some scientists and advocacy groups, like the Environmental Defence Fund, have argued that more research is needed to definitively say PFAS are not a risk. Diet is a major route of PFAS exposure — especially if that diet consists largely of fast food.

Partial Abstract:

Methods: We analyzed 2003–2014 serum PFAS and dietary recall data from the National Health and Nutrition Examination Survey (NHANES). We used multivariable linear regressions to investigate relationships between consumption of fast food, restaurant food, food eaten at home, and microwave popcorn and serum levels of perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorohexanesulfonic acid (PFHxS), and perfluorooctanesulfonic acid (PFOS).

Results: Calories of food eaten at home in the past 24 h had significant inverse associations with serum levels of all five PFASs; these associations were stronger in women. Consumption of meals from fast food/pizza restaurants and other restaurants was generally associated with higher serum PFAS concentrations, based on 24-h and 7-d recall, with limited statistical significance. Consumption of popcorn was associated with significantly higher serum levels of PFOA, PFNA, PFDA, and PFOS, based on 24-h and 12-month recall, up to a 63% (95% CI: 34, 99) increase in PFDA among those who ate popcorn daily over the last 12 months.