About 15 years ago, I treated a 15-month-old cat for congestive heart failure secondary to a severe, rare type of heart disease called dilated cardiomyopathy (DCM). This cat had a 6/6 heart murmur (We grade heart murmurs on a scale of 1-6, with 6 being the worst!), and it was all due to its diet. Turns out, this young cat developed the heart disease because his pet owner made him eat a vegetarian diet since he was a young kitten.
Thankfully, we don’t see this type of heart disease as much as we used to — thanks to better nutrition. Veterinarians were able to link certain types of DCM to the lack of a certain essential amino acid: taurine. An essential amino acid means that the body can’t make it, and it’s imperative that the diet contain it.
What did we learn from this? You cannot make your cat a vegetarian.
Dogs are omnivores while cats are strict carnivores. While there are cat vegetarian and vegan diets commercially available, these are never recommended by veterinarians (well, at least good ones). Please don’t make your cat a vegetarian.
If you want to cook for your cat (and can deal with having meat in your vegan refrigerator), then that’s OK, as long as you realize that it is very difficult to make a homemade, nutritionally balanced diet for your cat without screwing something up. If you want to attempt it, make sure it’s recommended by a board-certified veterinary nutritionist — and that does not mean trying whatever you stumble upon on the Internet!
Without appropriate supplementation, cats that are fed vegetarian or vegan diets are at high risk for other life-threatening deficiencies in amino acids and vitamins (e.g., lysine, tryptophan, vitamin A, etc.). It’s not worth the fatal risk.
Dogs on the other hand, can handle vegetable-based protein sources, so it is possible to make your dog a vegetarian. That said, dogs won’t like it. That’s because meat-based protein sources taste better. If you offered Fido a piece of corn versus a piece of steak, guess which one he’ll choose?
If you feel adamant about it, talk to your veterinarian or to a veterinary nutritionalist about it. It’s OK to make your dog vegetarian if you feel strongly about it, just make sure it’s a balanced diet (again, with the correct amino acids and multivitamins). Same goes for a homemade diet — it’s OK to do, just make sure you've consulted your veterinarian, or better yet, a veterinary nutritionalist.
As an emergency specialist, I’m pretty adept at treating congestive heart failure … but I prefer not to see DCM ever again. So help me out: Feed your pet a balanced diet!
What do you feed your cat or dog?
Dr. Justine Lee