Bisphenol-A & Hyperthyroidism

Cat Food in Pop Top Cans & other possible Risk Factors


I just heard about the possible link between bisphenol-A in pop-top canned cat food and hyperthyroidism.  How can I safely feed canned food to my cats? From another reader: I heard that tuna can cause hyperthyroidism in cats.


Dr. Nichol:

There is evidence that food from pop top cans may put cats at risk of hyperthyroidism (benign thyroid tumors) but other factors are clearly at work. A disease of older cats that causes weight loss, voracious appetites, and potentially fatal heart and kidney disease, hyperthyroidism is curable, especially in its early stages. We are seeing more of it and we need to know why.


It has been speculated that a substance called bisphenol-A, found in the lining of some pop top cans, may be responsible. Other research has shown more hyperthyroidism in some families suggesting a genetic link. And a flame retardant used during the same years as the spike in these cases has also gotten some attention.


We know that indoor cats are much more likely to be diagnosed with hyperthyroidism. This could implicate a substance in some types of cat litter or a household chemical. The average indoor cat gets much older than his footloose brethren putting him at greater risk for any geriatric disease. And since symptoms are easier to notice with indoor cats their problems are more likely to get diagnosed in the first place. Furthermore, 25% of hyperthyroid cats have never eaten any canned food. Tuna, with or without its mercury content, has not been implicated.


More research is needed. The official recommendation is to limit foods packaged in pop-top cans. Tony, the Nichol family cat, eats canned kitten food from, you guessed it, pop top cans. But he doesn’t smoke and he exercises regularly. Still, if anybody knows of kitten food in regular cans please contact me through my website ( Click submit?