Do You Feed Your Cat This Popular Food That Causes More HARM Than Good?

If you feed your feline fish or fish-flavored cat food their health could be in danger. Fish flavored cat food could be the main culprit in causing feline hyperthyroidism.

Feline hyperthyroidism has increased dramatically in the U.S. in the last 30+ years. It’s the most common endocrine disorder of barkery cat and fishkitties, with over 10 percent of cats over the age of 10 diagnosed with the disease.The thyroid is a butterfly-shaped gland at the base of the throat. When this little gland overproduces thyroid hormone, hyperthyroidism is the result. The disease is usually caused by a benign tumor on the thyroid gland called an adenoma. In rare cases, the tumor is a carcinoma, which is cancer.

Exposure to Flame Retardant Chemicals (PBDEs) Linked to Feline Hyperthyroidism

The sudden appearance and rapid increase in cases of hyperthyroidism in cats has generated quite a bit of research into potential causes, one of which appears to be exposure to flame retardant chemicals (polybrominated diphenyl ethers, or PBDEs). PBDEs are recognized endocrine and thyroid disruptors.

In a 2015 study published in the journal Environmental Science & Technology, researchers analyzed the blood from 60 pet cats for the presence of flame retardant chemicals, specifically decabromodiphenyl (BB-209), polybrominated diphenyl ethers (PBDEs), hydroxylated PBDEs (OH-PBDEs), and 2,4,6-TBP.1The objective of the study was to evaluate the differences in the levels of the chemicals in healthy cats and cats diagnosed with hyperthyroidism. Of the 60 cats in the study, 23 had normal thyroid function and 37 were hyperthyroid.The study results showed that the hyperthyroid cats had higher blood levels of PBDEs on a fat weight basis.Another earlier study published in the Journal of Toxicology and Environmental Health suggested that flame retardant chemicals in house dust are linked to thyroid disease in cats.2

The study authors concluded that cats are primarily exposed to flame retardant chemicals by ingesting house dust — which of course occurs every time they groom themselves.Indeed, housecats do seem to have extraordinary exposure to PBDEs. In 2012, Swedish researchers demonstrated that serum PBDE levels in Swedish cats were about 50 times higher than in the Swedish human population.And a 2007 study showed that PBDE levels in U.S. cats were 20 to 100-fold greater than median levels in U.S. adults.4

Fish-Flavored Cat Food Identified as Potential Culprit

A newly-released study seems to shed even more light on the connection between flame retardant compounds and feline hyperthyroidism, suggesting that fish-flavored cat food could be a culprit.5A team of Japanese scientists evaluated cat food and feline blood samples and discovered that the type of polychlorinated biphenyl (PCB) and PBDE byproducts found in both the food and blood samples are derived from marine organisms.The researchers were also able to simulate the way in which the bodies of cats convert the type of chemical present in the food into the type of chemical seen in the cats’ blood samples.Based on their results, the team concluded that the byproducts detected at high levels in cats’ blood samples likely came from fish-flavored food and not exposure to PCBs or PBDEs. However, further work is needed to determine the link between the metabolites (byproducts) and hyperthyroidism.

Tips for Helping Your Cat Avoid Hyperthyroidism

  1. Feed a balanced, fresh food, and species-appropriate diet
  2. Avoid feeding your cat a fish-based diet
  3. Also avoid feeding soy products to your kitty, as they have been linked to thyroid damage
  4. Rid your environment of flame retardant chemicals
  5. Provide your cat with an organic pet bed
  6. Purchase a high-quality air purifier for your cat’s environment


To ensure that your feline is getting the best food possible, stop by Brookside Barkery in Brookside or Lee’s Summit and talk with our trained staff to find the PURR-fect food for your cat!barkery_home_staff_bks

*Thank you to Dr. Becker for providing the information on feline hyperthyroidism.