A cat looking at a pig made of meat

Unhealthy Cat Food Ingredients To Avoid

Nutrition is a complicated topic. Even the experts disagree on what is safe and what isn’t. Today we’ll take a look at four types of food that were considered safe for cats in the past, but are now blacklisted.

1. Uncooked pork meat

If you take a look at the list of ingredients on your cat food, what you’ll usually find is that it contains multiple kinds of meat mixed together. Most commonly used are meat sources such as cow, chicken, lam, bird, salmon, duck and so on. But pig meat is rarely found on such a list. Why is that?

Pork meat poses a significant danger to felines

Aujeszky disease (aka pseudorabies) is caused by a virus known to be carried by pigs. The animals themselves are completely resistant to the virus, but cats are extremely sensitive to infection.1 Uncooked pig meat in particular is highly dangerous because it is very likely to contain viral Aujeszky.

Once the virus enters the body, it will spread to all parts of the nervous system and do tremendous damage within the span of a few days. There is currently no known cure for Aujeszky disease.

2. Canned tuna

When I was a kid, my grandpa would often spoil his cat with a big can of juicy tuna. We asked our vet Joanna if this is a good idea. Here’s what she had to say:

“Tinned tuna is not nutritionally complete, so giving too much can unbalance a cat’s diet. This food source is high in fat and contains a lot of calories – one 95g tin contains more than half of a cat’s daily allowance of calories! Canned fish meat like tuna and salmon often contain excess sodium (salt) which causes dehydration, changes in blood pressure, and puts strain on the kidneys.”

Joanna Woodnutt (MRCVS):

When tuna is given occasionally as a treat, the risk is limited. But once you start making canned fish a major part of a feline diet, all that fat and added sodium could become very detrimental to the health of your furry friend.

There is also the issue of rising mercury levels in fish meat2. This metal accumulates in the bodies of marine species that are higher up the food chain. Since cats have small bodies, a relatively small amount of mercury is enough to elicit symptoms of mercury poisoning, which could eventually progress into complete kidney failure.

3. Soy

Soy is a high-quality plant protein that contains many essential nutrients: It is high in vitamins and fibers, and contains little to no cholesterol. Since soy is essentially made up of the same building blocks as meat, cat food brands use it all the time as a cheap alternative to real meat. But research suggests that soy is not the healthiest of foods for cats in many regards.

Soy is linked to a number of negative side-effects

Being one of the most genetically modified plant species known to man, there is much discussion about the effects of soy in the body. A number of unfortunate side effects have been linked to the consumption of this plant protein:

  • The amount of indigestible fibre can lead to excessive gas production
  • Fiber also retains a lot of liquid, which can result in diarrhea
  • The large amount of carbohydrates may lead to blood sugar peaks (which is linked to diabetes)
  • Pyto-esterogen has an effect on hormone levels; has been proven to lead to developmental issues.
  • Anti-trypsine makes the metabolisation of proteins more difficult

Taking all these into consideration, I think it’s safe to say that soy is not a great alternative to meat in cat food. Stick to good old animal meat for your kitty.

4. Carrageenan

Carrageenan is an additive that is extracted from red seaweed commonly known as Irish Moss. It’s often used to thicken up foods and drinks while also functioning as a preservative. Carrageenan comes in two forms; degraded and undegraded. Research has shown that the degraded version is very bad for the feline body, causing ulcers and cancer in the stomach and digestive tract. Thankfully the FDA has banned this stuff, making it very unlikely to ever show up in a cat food product.

But that doesn’t mean you shouldn’t be concerned about carrageenan. The undegraded form of this substance is currently not banned and considered safe for consumption. This is a lie! The feline body can degrade carrageenan3, which effectively makes this form just as toxic.

Switching things up

So those are 4 ingredients that you definitely want to avoid from now on. If you read this article and discovered that your current cat food is no bueno, you’ll probably want to switch over to a different brand or product. Since cats are often pretty reluctant to try new things, we wrote this handy little guide on how to change a cat’s diet without getting angry stares.

1. https://www.petmd.com/cat/conditions/infectious-parasitic/c_ct_pseudorabies_virus_infection
2. https://www.edf.org/oceans/mercury-alert-canned-tuna-safe
3. https://twocrazycatladies.com/cat-food/no-one-tells-carrageenan-cat-food/


  1. So what food is the best for the cat’s. Usually i give or rather i by fish for my cat’s, i cooked with vinegar & when is done i mix with rice, also i lways buy cuties flavor tuna, is that good?

    1. Hey Gina 🙂

      Cooked fish meat is OK to give occasionally, but you really need to be careful not to feed too much of it. General guidelines state no more than 10% of daily calories. The reason is, some species of fish like tuna contain a lot of mercury, which will build up in your cat’s body and eventually cause mercury poisoning. In addition, fish meat does not contain all the essential nutrients cats need.

      Tuna-flavored food (from a brand like Cuties) is fine. The best food is one that is matched to your cat’s life phase (kitten, adult, senior) and has a balanced profile, which means it contains all the essential nutrients in the right proportions. You can give that as often as you want!

      Hope this answers all your questions!

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