Vegan diets are, for some people, perhaps a good choice. But many of my veterinary clients ask about the potential for feeding their cats such a diet. In answer to that question, a vegan diet is a poor choice for your cat. Such a diet cannot provide all of the nutrients that your cat requires for health.
It’s natural, in many ways, for a person who has made certain lifestyle choices to consider the same types of choices for their pet. In this case, if a vegan lifestyle and diet is important to you, your choice of pet cannot be a cat. There are many pets that you could choose that would thrive on a vegan diet but a cat is not one of them.
Cats, as a species, are obligate carnivores. In very simple terms, this means that cats require meat in their diet. They have specific nutrient needs that can only be supplied through the ingestion of animal meat.
Cats, like all other species, have very specific nutrient needs. They require certain proteins and other nutrients in their diet that are simply not found in plant sources.
Questions I sometimes hear are, “Isn’t a protein a protein?” and “Does it really matter where the protein comes from?” Here are the answers. There are many different types of proteins. Each protein is made up of amino acids. Amino acids are frequently referred to as the “building blocks” of protein. And each protein requires specific types of amino acids. So, one protein is not simply a protein like any other, and one amino acid is not either.
For instance, taurine is a specific amino acid that is required by all cats. Without sufficient amounts of taurine in the diet, cats can experience heart disease, vision problems, and other health issues. And cats cannot synthesize taurine by themselves. It needs to be provided through the diet. Taurine is not available through plants though. It is only available through animal sources (although there is a synthetic source).
Therefore, for a cat, the source of the protein definitely does matter. Cats not only require a higher protein level in their diet than other species (i.e., humans, dogs), but they also have a need for very specific proteins, and thus specific amino acids. Other essential amino acids for cats include methionine, arginine, and cysteine. These amino acids must be supplied in adequate quantities in the diet of all cats, also.
Amino acids are not the only nutrients required by cats that are not available through plant sources either. Others include Vitamin D, vitamin A, and arachidonic acid. In people, vitamin D is produced through exposure to sunlight. Cats lack the ability to do so, resulting in Vitamin D (in its active form of calcitriol) being a nutrient that needs to be provided in the food. It is rare in plant sources, except those fortified with synthetic vitamin D, but is found in animals and fish.
Vitamin A generally needs to be provided through animal sources as well. Cats cannot synthesize the active form of the vitamin from beta-carotene as other species can.
Arachidonic acid is an essential fatty acid for cats. Again, it needs to be provided in the food your cat is eating and is primarily available through animal sources.
As a result of these unique dietary requirements, without synthetic supplementation of the diet, a cat is unable to safely eat a vegan diet. Even with supplementation, producing a cat food that is complete and fills all of the nutritional needs of a cat is difficult (and dangerous) without adding meat to the diet. This is why they are referred to as obligate carnivores and require meat in their diet.
Enjoy the vegan diet for yourself, if that is your choice. But do not expect your cat to eat the same way.
Dr. Lorie Huston
Image: António Maneira / Flickr