Cats can be addicted to tuna, whether it's packed for cats or for humans. ... But a steady diet of tuna prepared for humans can lead to malnutrition because it won't have all the nutrients a cat needs. And, too much tuna can cause mercury poisoning.

Can cats safely eat tuna?

Although it's fine to feed your cat small amounts of tuna as a treat or as a supplement to her complete-and-balanced cat food, too much tuna can be harmful. ... Additionally, tuna is high in mercury, so too much tuna could potentially lead to a build-up of too mercury in your cat's body and lead to mercury poisoning.

How much tuna is safe for cats?

Until veterinarians know more, limit your cat's tuna consumption to occasional treats of canned chunk-light tuna—not albacore, which is from a larger species of tuna with mercury levels almost three times higher. These rare indulgences should account for no more than 10 percent of your cat's daily calories.