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Studies explore possible link between fish-flavored cat food and feline hyperthyroidism

A new study in Environmental Science Technology suggests that fish-flavored cat food could be among the culprits responsible for the number of cats diagnosed with hyperthyroidism.

Hyperthyroidism, a hormonal disorder that can cause weight loss, hyperactivity, aggression, vomiting and other symptoms in cats, has no known cause. Some studies have suggested a connection between environmental pollutants, specifically polychlorinated biphenyls (PCB) or polybrominated diphenyl ethers (PBDE); previous studies have detected these compounds and their byproducts in blood samples from cats. However, researchers theorized that the byproducts, which also can have toxic effects, could come naturally from other sources, such as fish, a common ingredient in cat food.

Researchers Hazuki Mizukawa, Kei Nomiyama and colleagues from the American Chemical Society, the world’s largest scientific society based in Washington, D.C., tested cat food and blood samples from cats. They also simulated how a feline’s body would process various toxic compounds. Based on their results, the team concluded that 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 researchers say further work is needed to clarify whether these metabolites specifically contribute to hyperthyroidism.


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