Person receiving restaurant food from drive-thru window

People who frequently eat meals prepared at home have lower levels of PFAS chemicals in their blood compared to those who often eat fast food, takeout, or restaurant meals, according to a new study published in the journal Environmental Health Perspectives.

PFAS—which stands for per- and polyfluoroalkyl substances—are ubiquitous in our environment. We’re exposed to them through many products we come into contact with regularly, including fabrics, nonstick pans, carpets, and waterproof gear. But—along with drinking water—diet is a major source of exposure, and food packaging is responsible for some of that exposure, though we’re still learning how much. 

Known as “forever chemicals,” PFAS don’t break down naturally and instead accumulate in the environment. At high levels of exposure, some have been linked to serious health problems, such as cancer, high cholesterol levels, obesity, thyroid disease, weakened immune system response, decreased fertility, and growth and learning delays in babies and children.

“Our findings show that decisions about what we eat and where we eat can have measurable changes on our PFAS exposure,” says Laurel Schaider, Ph.D., a research scientist at the Silent Spring Institute, a nonprofit that conducts research on the health effects of environmental chemicals, and an author of the study. “The more meals people ate at home, the lower their PFAS levels appeared to be.” 

What the Study Found

Schaider and colleagues analyzed data from more than 10,000 people who participated in the National Health and Nutrition Examination Survey (NHANES) between 2003 and 2014. Since 1999, NHANES has measured PFAS levels in people’s blood, and participants also answered questions about food they’d eaten over the past day, week, month, and year.

Previous research has shown that some fast-food packaging contains PFAS chemicals, and so Schaider says they wanted to find out if people who ate more fast food had higher blood levels of these substances.

More on Concerning Chemicals

We’re still learning more about the key sources of exposure but diet is an important one, according to Holly Davies, Ph.D., a senior toxicologist at the Washington State Department of Health, who was not involved in the study. “We’ve seen associations with microwave popcorn and fish before,” says Davies. These foods are known to expose people to PFAS chemicals; fish absorb PFAS that accumulate in the water and the coating used in microwave popcorn bags contain PFAS. But this is the first time that we’ve seen how the way meals are eaten correlates with PFAS exposure, she says, giving us a better picture of how our eating habits affect PFAS levels.

The clearest finding from the new research, Schaider says, is that people who dined at home the most had lower levels of PFAS. For every 100 calories of non-restaurant food eaten at home, blood levels of five types of PFAS were 0.32 percent lower. 

However, the research team analyzed microwave popcorn consumption (often eaten at home) separately, and found that the more people reported eating it, the higher levels of certain PFAS chemicals they had in the blood.

The PFAS/Diet Connection

The study authors say their findings indicate that food from restaurants, fast-food establishments, and pizza shops could be more likely to be packaged in PFAS-lined grease-proof containers. 

When people eat out, their food may be more likely to come into contact with PFAS-containing boxes and wrappings, according to Schaider, and those chemicals could be migrating into food, according to this study and previous research. The foods people eat while dining out could potentially be more likely to contain PFAS, she says. 

It’s also possible that instead of chemicals migrating from packaging into food, these chemicals are traveling from the packaging onto people’s hands and then into their mouths, says Graham Peaslee, Ph.D., a professor of experimental nuclear physics at the University of Notre Dame who conducts research on PFAS chemicals.

Companies that make food packaging have been moving away from using PFAS over the past few years, says Peaslee. But even if burger wrappers and pizza boxes are becoming less likely to be a source of PFAS, some newer types of food packaging may still be problematic. For example, this year, in partnership with The New Food Economy, a nonprofit news website focused on food, Peaslee tested a number of supposedly eco-friendly compostable bowls that restaurants have started to use in an effort to move away from plastics. All of those bowls contained PFAS. 

PFAS Health Concerns

There are more than 4,700 types of PFAS chemicals that have been created, with hundreds currently in use.

There’s clear evidence that some of the best-studied older PFAS chemicals, like PFOS and PFOA, are harmful to human health. Because of that, some of these chemicals are being phased out, at least in the U.S. and Europe. But less is known about the newer PFAS chemicals that are used in their place.

Industry representatives say that these newer PFAS chemicals are safe. “New FluoroTechnology products are based on different chemistry, and this new chemistry has a favorable health and safety profile,” Rob Simon, a spokesman for the FluoroCouncil, previously told CR. FluoroCouncil representatives did not respond to a request for comment for this story.

But many scientists are not convinced. “What we’re finding out about the other [newer] compounds isn’t good,” says Davies. Data indicates newer PFAS chemicals stay in the human body for weeks or months instead of years—as the older chemicals do—but that’s still long enough for them to accumulate at worrying levels, according to Schaider. 

How to Reduce PFAS Exposure

Because their use is so widespread, you can’t totally avoid PFAS, and don’t need to—some products we use that have PFAS in them don’t necessarily expose us to concerning levels of these substances. But “it’s a good idea to reduce exposure where possible,” says Davies. Here are some tips for keeping PFAS out of your diet.

Cook fresh food at home. “We all know there are a lot of good reasons to eat more home cooked meals and more fresh foods and this [study] is another reason,” says Schaider. Home-cooked meals are often more nutritious, and the fresher your food is, the less likely it will be to have been exposed to packaging that may contain PFAS or other concerning chemicals.

When you eat out, minimize exposure to packaging. It’s worth simply unwrapping your food as soon as you can, and don’t store it or reheat it in the packaging it came in. “Migration [of chemicals] increases with time and heat,” says Davies.

Check your drinking water. The EPA doesn't currently require routine monitoring for PFAS, but some states do. Contact your local water utility to see whether there’s ongoing testing for PFAS chemicals, which can also be called PFCs. You can also check older data from a few years when EPA required testing or look at this map created by researchers from the Environmental Working Group and Northeastern University based on that data. (For more, see this story, but don’t assume bottled water is safer.)

Consumers who learn that their water has high levels of PFAS chemicals in it should consider installing reverse-osmosis filters or carbon filters, though these may not work as well for some of the newer alternative chemicals.

Don’t microwave bags of popcorn. Use an air-popper or make popcorn on the stove, says Schaider.

Check your cookware. While most nonstick pans contain PFAS chemicals, it’s unlikely these chemicals are released during normal use, if the pans aren’t overheated or scraped. Still, since eventually these chemicals might be released when these pans are disposed of, some experts recommend opting for other options. Here are some stainless steel and cast iron items CR recommends. 

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