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Is There Mercury in Cat Food? Vet-Reviewed Facts & FAQ

woman reading pet food label
Image credit: Caftor, Shutterstock
Last Updated on November 16, 2023 by Christian Adams

Vet approved

	Dr. Maxbetter Vizelberg DVM Photo

Reviewed & Fact-Checked By

Dr. Maxbetter Vizelberg DVM

The information is current and up-to-date in accordance with the latest veterinarian research.

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As a cat lover, you understand how irresistible a fishy dish can be for our feline friends. Because we naturally want to feed them the best we can and reward them with their favorite treats, it’s normal to reach for the fish-flavored kibble or the gourmet tin of cat tuna because you know it will win over your pet.

While cat food does contain mercury, the concentrations are below the suggested levels. This is not to say that you need to pull fish from your cat’s diet altogether, and you don’t need to get into a worried frenzy, but it’s helpful to understand how mercury can affect your kitty and how you can reduce the risk of high mercury exposure.

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Is Mercury a Concern in Cat Food?

cat eating food at home
Image Credit: Africa Studio, Shutterstock

Ingesting fish is the primary cause of mercury exposure for cats, and high exposure to mercury in cat food can lead to significant problems for your kitty. If your cat’s diet is made up primarily of fish, then there could be room for concern, but it doesn’t mean you need to remove it from your cat’s diet completely.

The amount of mercury in fish varies according to the type and size of the fish and the waters in which it lives. Tuna, a cat’s common favorite, contains higher levels of mercury than several other fish.

Sadly, the regulations for the use of fish in pet food aren’t very strict, and some commercial foods contain small amounts of fish that are labeled as poultry, beef, or other proteins. Because mercury levels in pet food are not regulated in the United States, there is no direct way to improve the safety of commercial diets.

Why Does Fish Contain Mercury?

Because of human pollution, mercury enters the atmosphere and eventually settles in water. Certain microorganisms then convert this heavy metal into methylmercury, which is a highly toxic form that accumulates in fish and the animals that consume them. Nearly all fish contain traces of mercury and methylmercury, but some common ones are tilefish, tuna, king mackerel, swordfish, and sharks.

Why is Mercury a Concern?

tabby cat lying on the floor
Image Credit: Piqsels

When too much mercury is ingested, it can affect the lungs, brain, and kidneys. Your cat can also develop mercury poisoning. Because methylmercury tends to accumulate in the body, symptoms of mercury poisoning in cats are primarily caused by damage to the nervous system. The kidneys are also frequently affected. Mercury poisoning in cats can mimic other reactions to poison ingestion, vitamin B1 deficiency, brain tumors, and other ailments that cause neurological impairment. Signs of mercury poisoning can include:

  • Loss of concentration
  • Dizziness
  • Abnormal behavior
  • Tremors and seizures
  • Paralysis
  • Blindness
  • Depression of the central nervous system
  • Involuntary eye and body movements
  • Ataxia
  • Death

Unfortunately, no specific antidote exists for chronic methylmercury toxicity, but supportive care and preventing exposure in the future can help your feline friend.

If damage has been caused to the organs, it is sadly irreversible. If your cat survives, its kidney function may be reduced, and it may be left with permanent neurological impairments.

How To Keep Your Cat Safe from Mercury?

woman with a push cart in grocery buying cat food
Image Credit: LADO, Shutterstock

While most cats have a low chance of being poisoned by mercury, there are some precautions you can take to keep your cat as safe as possible.

If your cat needs a fish-based diet, you should examine the food labels carefully. The Natural Resources Defense Council maintains a Consumer Guide to Mercury in Fish, which ranks fish by mercury content from lowest to highest, so when reading cat food labels, you can use the list as a guide.

If your cat is already an avid fish eater, you may need to alternate fish and non-fish foods for a while, gradually lessening the number of cans of tuna-based foods over time.

It is advised to minimize the number of fish meals included in your cat’s diet to help minimize the risk of mercury poisoning. Small fish like sardines in spring water or freeze-dried minnows are good choices for an occasional treat or a portion of a complete and balanced meal.

If you give your cat canned tuna as a treat, choose the light chunk variety rather than albacore.

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Fish consumption is the primary route for mercury to make its way into your cat’s system, and if your cat’s diet is high in fish, you may want to reign that in a little. Cutting out fish entirely is unnecessary, but you can reduce your cat’s exposure to mercury by learning which fish to avoid, which are safest to feed your cat, and how frequently a treat can be given.

Featured Image Credit: Caftor, Shutterstock

About the Author

Christian Adams
Christian Adams
Christian is the Editor-in-Chief of Excited Cats and one of its original and primary contributors. A lifelong cat lover, now based in South East Asia, Christian and his wife are the proud parents of an 11-year-old son and four rescue cats: Trixie, Chloe, Sparky, and Chopper.

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