Processed and Packaged Foods Increase PFAS Levels in Human Blood, Study Finds

A new study led by researchers from University of Southern California (USC)’s Keck School of Medicine has found that certain foods — like processed meats, hot dogs, teas and foods not prepared at home — are likely to contain higher levels of PFAS “forever chemicals.”

Per- and polyfluoroalkyl substances (PFAS) are a group of thousands of synthetic chemicals used in consumer products and household items like food packaging, nonstick cookware, clothing and furniture. Deemed “forever chemicals” because they do not break down quickly or easily, their widespread use has led to them becoming ubiquitous in water, air and soil, as well as in the bodies of humans and other animals.

The study found that diet and PFAS exposure are closely linked, and that consumption of foods with higher levels can result in accumulation in the human body over time, a press release from the Keck School of Medicine said.

“The main takeaway is not to demonize certain foods or say, ‘Oh my gosh, this food is so unhealthy.’ The point is to highlight that we need more testing of these foods, and this gives us an avenue to say, ‘OK, these foods may have higher levels of PFAS so we should do more targeted monitoring of them,’” said Hailey Hampson, lead author of the study and a doctoral student in the division of environmental health at Keck, as The Guardian reported.

The researchers studied two groups of young adults — 123, primarily Hispanic, with the Southern California Children’s Health Study (CHS), and a “nationally representative sample” of 604 young adults with the National Health and Nutrition Examination Study (NHANES), the press release said. The research team found that consuming certain foods, including those that are prepared at restaurants, was associated with higher PFAS levels in the human body.

“To our knowledge, this is the first study to examine how dietary factors are associated with changes in PFAS over time,” Jesse A. Goodrich, senior author of the study and a Keck School of Medicine assistant professor of population and public health sciences, said in the press release. “Looking at multiple time points gives us an idea of how changing people’s diets might actually impact PFAS levels.”

The study was published in the journal Environment International.

The results highlight the importance of monitoring and testing a variety of foods and beverages for PFAS contamination.

“We’re starting to see that even foods that are metabolically quite healthy can be contaminated with PFAS,” Hampson said. “These findings highlight the need to look at what constitutes ‘healthy’ food in a different way.”

Participants in the study answered questions regarding their diets, including the frequency with which they ate certain foods and beverages — such as dark green vegetables, bread, milk, sports drinks and tea. They were also asked how often they consumed foods from fast-food and non-fast-food restaurants and how often they ate home-cooked foods. The researchers used this information to hypothesize how often the participants came into contact with food packaging — a common source of PFAS.

Blood samples from the participants were tested for PFAS levels. The group from CHS was tested once at roughly the age of 20, as well as at around age 24, while the NHANES group was only tested around the age of 19.

The CHS group members who reported a higher consumption of tea in the first go-round were found to have higher PFAS levels during the second visit. A 24.8 percent higher level of perfluoro- hexanesulphonic acid (PFHxS) was found with one additional serving, along with a 16.17 percent higher level of perfluoroheptanesulfonic acid (PFHpS) and a 12.6 percent higher incidence of perfluorononanoic acid (PFNA).

Participants who reported higher pork intake were also found to have higher PFAS levels at the second visit, with one added serving associated with a 13.4 percent higher level of perfluorooctanoic acid (PFOA).

Foods prepared at home were found to have the opposite effect. Every increase of approximately 7.06 ounces of home-cooked foods equated to 0.9 percent lower baseline levels of perfluorooctanesulfonic acid (PFOS) and 1.6 percent lower at the time of the second visit.

“It’s really interesting to find that these foods that are maybe not so healthy, when they’re cooked at home were a lower source of PFAS, and that definitely points to food packaging,” Hampson said, according to The Guardian.

The researchers said the pervasiveness of food packaging might call for a tougher strategy. Last year, an advisory letter was issued by the attorney general of California asking paper straw and food packaging manufacturers to disclose levels of PFAS in their products.

“That’s a really good step in the right direction, and our findings highlight the need for more of those types of regulations across the country,” Goodrich commented.