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Tuna, Milk and Other Foods Cats Should Not Eat


People who love their cats also often like to give them treats like tuna, milk, cheese, raw meat, and other goodies. Yet these and other common foods can be harmful, even deadly to cats, and they should be avoided.

Milk and other dairy foods are a no-no for cats, either as a treat or as a substitute for water. Although kittens may be able to handle a very small amount of milk, adult cats cannot. Cats do not have a significant amount of lactase, the enzyme that breaks down the lactose in milk and milk products, to digest these foods properly. If you feed milk, cheese, and other dairy foods to your cat, vomiting, diarrhea, and food allergies may result.

Tuna would definitely be on every cat’s shopping list if they were allowed to roam the supermarket aisles, but a steady diet of tuna can result in malnutrition. Another concern is mercury poisoning (which is a concern for humans as well). The human variety of tuna contains enzyme that destroys thiamine, and so cats who regularly eat tuna can develop a thiamine deficiency, which can cause neurological symptoms such as loss of equilibrium and seizures if not corrected.

Chocolate may be one of your favorite foods, but it should not be on your cat’s plate. Actually, most cats will not eat chocolate unless they are encouraged, and in this case cats know best. Chocolate can be lethal for cats because it contains theobromine. Dark chocolate and unsweetened baking chocolate contain higher amounts of this substance, which can cause seizures, abnormal heart rhythms, tremors, and even death in cats.

Caffeine may be a pick-me-up for you, but for cats it can be deadly in large enough doses. Cats who consume caffeine from coffee, tea, cola, cocoa, or stimulant drinks can experience caffeine poisoning, which is characterized by rapid breathing, muscle tremors, fits, and bleeding. There is no antidote.

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Table scraps such as bones or fat trimmed from meat should never be given to cats. Bones can cause a cat to choke, or they can splinter and lacerate a cat’s digestive system. Fat can cause pancreatitis.

Raw meat, fish, and eggs can cause food poisoning, as they can in humans. Another reason to avoid giving raw fish to your cat is that it contains an enzyme that destroys thiamine, as does tuna. Raw eggs also contain avidin, an enzyme that blocks the absorption of the vitamin biotin, which can lead to skin problems.

Alcohol, in the form of beer, wine, liquor, or foods that contain alcohol, can impact your cat’s brain and liver. Three teaspoons of liquor can kill a five-pound cat. Put a smile on your cat’s face with catnip, not a nip from a liquor bottle.

Dog food is for dogs—that’s why they make it. Although an occasional bite or two of dog food won’t hurt your cat, a steady diet can cause malnutrition because dog food does not contain all the nutrients a cat needs.

Other foods that your cat should not be fed include onions, garlic, and chives (anemia, gastrointestinal upset); grapes and raisins (kidney failure); liver (too much can cause vitamin A toxicity); sweets that contain xylitol (drop in blood sugar leading to liver failure); and sugar (obesity, diabetes).

There are many cat treats on the market that are healthful for your cat. To help ensure your cat enjoys a long, happy life, avoid indulging him or her with tuna, milk, or other goodies you consider to be a treat. If your cat should eat something that makes him or her ill, contact your vet immediately. If it is an emergency, you can also call the ASPCA Animal Poison Control Center at 1-888-426-4435.

American Animal Hospital Association
American Society for the Prevention of Cruelty to Animals
Humane Society of the United States
WebMD Dec. 11, 2009



Hmm... what do you mean when you say that "the human variety of tuna contains an enzyme that destroys thiamine"? Does the tuna found in pet food not contain this enzyme?
I'm unaware of any difference in tuna variety. If there is a difference you can bet that it's not good for humans either. I'm really wondering about the chocolate thing because I have a cat that eats chocolate regularly in small amounts. I have to hide it from her or she will eat a little off of it. She really likes the dark/baker type chocolate, not so much on the milk chocolate. Dogs will inhale so much of a substance that it's easy to overeat. In general cats don't overeat. Chocolate can poison humans too, but small amounts prove healthful. I'd bet that a cat eating small amounts is the same thing, although their metabolism is a little different. If your cat eats a huge amount maybe you should worry.
Any amount of chocolate is bad for cats!!!! Not only is the chocolate itself Toxic for them, but chocolate also contains caffeine, which is one of the most poisonous substances a cat can heat, which causes thier body and organ systems to shut down!!! Mycat almost died when she got a hold of a chocolate muffin from the garbage. Please do not give your cat chocolate.
Yep, all we should give to our cats is commercial cat food ( dry or canned)...I get it. Poor feral cats and farm cats I wonder how the survive on raw mice and birds. you You are really beyond common sense with this kind of advice.
Thank you for your comments. However, I think you may have missed the point of the article: I'm talking about giving cats food that is meant for people. Wild cats are natural carnivores and do hunt and kill their own food. Domesticated cats do not need to hunt and kill for their supper, and personally I prefer to feed my cats food that has been designed for their consumption. (And no, I do not have stock in pet food companies.) Feral cats have little choice but to hunt for their own food, but even they can get into garbage cans and eat food meant for human consumption and be sickened by it. People shouldn't eat raw mice; cat shouldn't eat chocolate.
Did you know that sodium pentobarbital is found in most processed pet food as a result of recycling euthanised pets? And why don't you mention all the cat and dog deaths from melamine poisoning (2009), and cancer from preservatives that are banned from human consumption (BHA/BHT/propylene glycol, ehtoxyquin), thiamine deficiency (from SO2), irradiation.... from eating processed food? You can get the list from the FDA (Pet Food Recall List). Do you think you would be a healthier, happier individual if you were forced to eat the same artificial stuff everyday?
Thank you for sharing this information. Obviously this article does not cover EVERYTHING that is bad for cats, and the additives in pet food--either intentional or unintentional--are among them. I am not personally advocating feeding your cat commercial pet food either. In fact, I don't feed my cat the same thing each day and I prepare his food from scratch. An entire book could be written on the dangers of commercial pet food! I will attempt to tackle some of these issues in future articles.
Raw meat is the best thing you can give your cat if it's processed properly. There are places were you can buy ground rabbit etc, with fur bones and organs that provide a healthy diet for your cat. Raw meat you buy at the grocery store should be avoided of course; but raw in and of itself is not a problem.
Yes, I am aware of the school of thought that advocates feeding cats raw meat. After all, cats are true carnivores and our domesticated cats would gladly kill and devour their own food if they needed to. However, feeding cats raw meat is not palatable for every cat parent, including this one. And it can be a cost factor for some people as well. That does not mean cat parents should not feed their cats the best quality and most appropriate food they can afford. Thank you for your comments!
Weird thing about tuna... but makes sense, however, would Salmon come under that umbrella as well? I have found that even when I don't feed my kitty Tuna regularly, he just pukes it up unless it's a tiny bit as a treat. He does it with Salmon too. I am wondering if that's because it is stringy in texture, and triggers their hairball regurgitation urge?
Hi Astro Kitty's mom: I'm not a vet, but my guess is that your kitty just doesn't process these fish well. The general consensus is that tuna in small amounts and occasionally may be okay for kitties, but that too much can be harmful because it does not contain all the nutrients cats need. Cat food that contains tuna, however, has been processed to contain those ingredients.