A new study from the University of North Carolina Chapel Hill (UNC Chapel Hill) Gillings School of Global Public Health is shedding light on how dietary choices may influence exposure to per- and polyfluoroalkyl substances (PFAS). Also called “forever chemicals” due to their inability to break down in the human body or the environment, PFAS are a class of synthetic chemicals used in consumer goods like cookware and food packaging, and which are increasingly acknowledged as harmful to human health.

Published in the International Journal of Hygiene and Environmental Health, the researchers analyzed blood samples from more than 11,000 individuals aged 12 and older, using data from the U.S. Centers for Disease Control and Prevention’s (CDC’s) National Health and Nutrition Examination Survey for 2003–2018. The researchers also averaged responses from two 24-hour dietary recalls to calculate relative intakes of foods classified based on the NOVA system, which groups items into four categories based on their level of processing (i.e., unprocessed/minimally processed foods, processed culinary ingredients, processed foods, and ultra-processed foods.).

The researchers found that individuals who consumed more ultra-processed foods—particularly adolescents and those with a healthy body weight—had elevated levels of two PFAS compounds: PFHxS and MeFOSAA. Specifically, each 10 percent increase in ultra-processed food intake was associated with higher PFHxS. Additionally, each 10 percent increase in unprocessed/minimally processed food intake was associated with lower perfluorooctanoic acid PFOA, PFNA, PFDA, and PFUnDA.

These findings suggest that food packaging, food contact materials used in processing, and processing methods may be significant contributors to PFAS in food, increasing dietary exposure.

However, the study also revealed that PFAS exposure is not limited to processed foods. Participants who primarily consumed unprocessed foods still showed elevated levels of other PFAS compounds, such as PFDA and PFUnDA. This points to additional exposure pathways, including contaminated drinking water, soil, and bioaccumulation in fish and meat.

Although dietary changes may help reduce exposure, as well as other choices like using PFAS-free cookware and filtering drinking water, the researchers say that personal choice is not a complete solution. They stress the need for systemic interventions, including stronger food safety regulations and environmental remediation efforts.

The findings add to a growing body of evidence that PFAS contamination is a multifaceted issue, with implications for food safety, public health, and environmental policy. As researchers continue to investigate the sources and impacts of PFAS, the study underscores the importance of addressing chemical exposure through both consumer awareness and regulatory reform.

Credited as lead author on the study is postdoctoral researcher Diana C. Pacyga, Ph.D., joined by Jessie P. Buckley, Ph.D., Associate Professor of Epidemiology.