A study of commercial pet foods in Japan has found elevated levels of forever chemicals, known as PFAS, particularly in fish-based products for cats and dogs. These levels often exceed human safety thresholds set by European regulators. Researchers urge better monitoring to assess risks to companion animals.
Researchers at Ehime University in Japan analyzed 100 commercial pet foods sold between 2018 and 2020, including 48 dog varieties and 52 cat options, both wet and dry. They tested for 34 types of perfluoroalkyl and polyfluoroalkyl substances (PFAS), persistent artificial chemicals linked to health issues in humans such as liver damage and certain cancers. In pets, limited studies associate some PFAS with liver, thyroid, kidney, and respiratory diseases in cats.
The team calculated daily PFAS intake based on typical meal sizes and animal body weights. Several products showed moderate to high concentrations, surpassing daily limits per kilogram of body weight established by the European Food Safety Authority (EFSA) for humans. For dog foods, Japanese grain-based options had some of the highest levels, potentially from agricultural runoff or fish byproducts. Meat-based dog foods generally contained low or no PFAS, including one Japanese brand and two Australian ones.
Cat foods, especially fish-based ones from Asia, the US, and Europe, exhibited the highest PFAS, with a Thai-made wet fish product standing out. Kei Nomiyama, the lead researcher, explained that oceans serve as sinks for synthetic chemicals, allowing PFAS to concentrate in aquatic food chains. He noted regional variations likely stem from production histories and sourcing differences, calling for harmonized global monitoring.
"Our findings do not indicate an immediate health emergency, but they do highlight a knowledge gap," Nomiyama said. He suggested pet owners diversify protein sources to reduce exposure. EFSA stated its human limits do not directly apply to animals, though Nomiyama emphasized the need for pet-specific risk assessments, viewing companion animals as indicators of environmental pollution.
Håkon Austad Langberg from Akvaplan-niva in Norway described the results as expected, given PFAS's global presence and bioaccumulation. He highlighted cumulative exposures from multiple sources as the broader challenge. The study appears in Environmental Pollution (DOI: 10.1016/j.envpol.2026.127779).
