Fast food isn't exactly known for its health benefits, but a new US study suggests even the packaging may be harmful.
That's because the study found one-third of fast food packaging contains chemicals known as PFASs (for polyfluoroalkyl and perfluoroalkyl substances) that give it stain-resistant, water-repellant and nonstick properties. The trouble is these fluorinated chemicals have also been linked to an increased risk of certain cancers, hormone problems, high cholesterol, obesity and immune suppression in human and animal studies.
"Our study is the most comprehensive assessment of how common fluorinated chemicals are in fast food wrappers in the US, and which types of wrappers are most likely to contain them," said lead study author Laurel Schaider of the Silent Spring Institute in Newton, Massachusetts.
"We found that nearly half of paper wrappers, for instance wrappers for sandwiches and burgers and flat bags for cookies and pastries, contained fluorinated chemicals, and that around 20 per cent of paperboard packaging, for instance boxes for French fries and fried foods, contained fluorinated chemicals," Schaider added by email.
PFASs aren't found naturally in the environment. These man-made chemicals have been used for decades in products ranging from food wrappers to clothing, nonstick cookware and fire-fighting foams. People may be exposed to PFASs from direct contact with these products, through the air they breathe, the food they eat and the water they drink.
For the study, Schaider and colleagues tested for PFASs in more than 400 samples of paper wrappers, paperboard and drink containers from 27 fast food chains across the US
More than half of the tests were done on food contact paper, including 138 wrappers for sandwiches or burgers, 68 wrappers for dessert or bread and 42 wrappers for Tex-Mex foods.
Overall, 46 per cent of paper wrappers tested positive for PFASs. This included 38 per cent of sandwich and burger wrappers, 56 per cent of bread or dessert wrappers and 57 per cent of wrappers for Tex-Mex food, researchers report in Environmental Science and Technology Letters.
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Tests of 30 samples from paper cups didn't turn up any of these chemicals. But in tests of 25 other beverage containers, 16 per cent did have PFASs.
Researchers also did more extensive testing on a subset of 20 samples to see what types of PFASs were in the food packaging. Six of these samples contained a type of PFASs called PFOA (perfluorooctanoic acid, or C8) that many US manufacturers voluntarily stopped using in 2011 due to concerns about the potential health risks.
One limitation of the study is that researchers were unable to assess how often people came into contact with these chemicals in food packaging, the authors note.
Still, the results show that even chemicals being phased out due to health concerns are still widely used, said Dr. Leonardo Trasande, an environmental medicine researcher at New York University School of Medicine who wasn't involved in the study.
"This study reinforces the reality that these chemicals are highly persistent in the environment, and may find their ways into people's bodies for years after they are no longer intentionally added," Trasande said by email.
"This study adds to concerns about chemicals that contaminate highly processed or packaged foods, potentially magnifying health effects above and beyond the effects that may result from their high-fat or high-sugar content," Trasande added.
Avoiding fast food is one way to limit exposure.
Serving food in wax paper instead of grease-resistant wrappers typically used in food packaging might also reduce contact with the chemicals, Trasande said.
Diners can also limit exposure by avoiding oily food, high-temperature food and taking food out of wrappers right away so it has less contact time with any chemicals, said Xindi Hu, an environmental health researcher at Harvard T.H. Chan School of Public Health in Boston who wasn't involved in the study.
Whenever possible, customers should avoid disposable packaging, Hu added by email.
"If they are dining in, then it is not necessary to use paper plates," Hu said. "Some restaurants do not provide regular dishes for logistical reasons, but from the perspective of reducing exposure to chemicals in food packaging, it is actually encouraged that restaurants use more regular dishes."