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Nutrition Nuggets is the newest offshoot of petMD's Dog Nutrition Center. Each week Dr. Coates will use her expertise and wisdom to blog about the intricacies of dog nutrition.

More Evidence That Dogs Can Be Vegetarians… And Cats Can’t

August 28, 2015 / (6) comments

We’ve talked before about whether or not dogs and cats can be vegetarians. My answer has always been “yes” for dogs as long as they eat a food that has been carefully designed to meet all of their nutritional needs, and “no” for cats, since they are true, obligate carnivores and need to eat amino acids that can only be found in animal-based sources of protein.


I recently came across some new research that reinforces the idea that vegetarian diets can be a reasonable option for dogs but not for cats. The study looked at the overall amount of protein present and the concentrations of specific amino acids (the building blocks that the body uses to build its own proteins) in 24 over-the-counter and veterinary therapeutic vegetarian/vegan diets for dogs and cats.


The scientists used accepted techniques to determine the foods’ crude protein levels and amino acid concentrations and compared these numbers to the minimum requirements put forth in the Association of American Feed Control Officials (AAFCO) Dog and Cat Food Nutrient Profiles for growth and adult maintenance. To paraphrase their most pertinent results, 23 of the 24 foods met or exceeded the AAFCO minimum for crude (total) protein, and 18 diets contained all amino acids in concentrations that met or exceeded the minimum AAFCO values. BUT:

  • Five diets (all for cats; 3 dry and 2 canned) provided 1 or more amino acids at concentrations below the AAFCO minimum value. Of these 5 diets, 1 was below the AAFCO minimum requirements in 4 amino acids (leucine, methionine, methionine-cystine, and taurine), 1 was below in 3 amino acids (methionine, methionine-cystine, and taurine), 2 were below in 2 amino acids (lysine and tryptophan), and 1 was below in 1 amino acid (tryptophan). An additional canned diet intended for both dogs and cats exceeded the amino acid minimum values for dogs but was below the minimum values for cats for 3 amino acids (methionine, methionine-cystine, and taurine).
  • All of the canned diets formulated for cats (2 for cats and 1 for both dogs and cats) were below the AAFCO minimum value for taurine.
  • Overall, of the diets that contained 1 or more amino acids at concentrations below AAFCO minimum values, the amino acid concentrations ranged from 34% to 98% (median, 82%) of the minimum requirement stated in the AAFCO Dog and Cat Food Nutrient Profile.


In short, the dog foods had all the amino acids that this species needs, while six of the diets labeled for cats were deficient.


So if you are in the market for a vegetarian/vegan dog food, it looks like you can be fairly confident that what is available on the shelves will give dogs the specific amino acids they need to be healthy. Unfortunately, the same cannot be said for cats.


Dr. Jennifer Coates




Assessment of protein and amino acid concentrations and labeling adequacy of commercial vegetarian diets formulated for dogs and cats. Kanakubo K, Fascetti AJ, Larsen JA. J Am Vet Med Assoc. 2015 Aug 15;247(4):385-92. 



Image: Tibanna79 / Shutterstock


Comments  6

Leave Comment
  • Cat Food
    08/29/2015 06:33pm

    "canned diet intended for both dogs and cats"

    Other than A/D, I wasn't aware there were any foods on the market that were marketed for both dogs and cats.

    Although it sounds like it/they would be nutritious, I'm not sure I would be comfortable feeding my kitties something like that. I'll have to talk to my vet about that to see if he's familiar with it/them and what his opinion is.

  • No Scientific Proof
    09/11/2015 06:06pm

    This article did NOT show any scientific proof that dogs are herbivores. And listing a bunch of synthetic vitamins on a can of commercial pet food is NOT proof of a nutritionally balanced diet. Any living thing eating processed, denatured "food" day in and day out cannot thrive.

    Dogs are carnivores; not herbivores. They do not have an enzyme to break down and digest cellulose. They do not have amalyse in their saliva to break down starches/Carbs. Dogs have a short digestive system that is typical of a carnivore. They have sharp, pointy teeth to rip and tear flesh off a prey animal. They do not have flat molars or a jaw that moves side to side to grind plant matter into a pulp.

    Pushing vegan diets packed with artificial nutrients on people's dogs is just another example of irresponsible health care in the allopathic veterinary community.

  • 75% is acceptable??
    09/11/2015 06:40pm

    I'm sorry, but if 25% (6 of 24) of these foods don't meed minimum requirements (which are truly minimal) for amino acids, how does this leave me "fairly confident that what is available on the shelves will give dogs the specific amino acids they need to be healthy?" And although taurine, which is only available from animal sources, is still not included in AAFCO standards, studies* have found it to be conditionally essential for at least some dogs, who could be seriously harmed by too little taurine in these diets.

    * Taurine deficiency in dogs with dilated cardiomyopathy 12 cases (1997-2001). Fascetti AJ, Reed JR, Rogers QR, Backus RC. 8, s.l. : J Am Vet Med Assoc, 2003, Vol. 223. 1137-41.

  • 09/11/2015 08:53pm

    The foods that failed to meet the minimum requirements were for cats. The canine diets all "passed."

  • 09/11/2015 09:20pm

    Sorry, I misunderstood about the amino acid findings, though my question about taurine remains. Too little taurine, even in diets that contain meat, can cause dilated cardiomyopathy in some dogs. A vegan diet would not contain taurine, and a vegetarian diet would likely not have enough unless it were added separately.

  • wrong
    09/11/2015 07:37pm

    dogs are NOT vegetarians..they are carnivores. anyone who would fed a dog a crap diet of all or mostly veggies should NOT be allowed near a dog. try a raw diet and feed them what they should be eating.