No one knows for sure what causes feline hyperthyroidism, but some studies suggest a connection to environmental pollutants such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). A new study suggests otherwise.

A team of researchers in Japan sought to test whether cats were getting exposed from their fish-flavored food. (Toxic byproducts also come naturally from sources such as fish, a common ingredient in cat food.)

The researchers concluded that, indeed, the byproducts that were detected at high levels in cats’ blood samples likely came from fish-flavored food and not exposure to PCBs or PBDEs.

The study was published Dec. 2 in the American Chemistry Society’s Environmental Science & Technology journal.

Specifically, the researchers tested cat food and blood samples from cats. They also simulated how a feline’s body would process various PCB- and PBDE-related compounds. 

Photo credit: © iStock/Mercedes Rancano Otero