Vegetarian and Vegan Diets for Dogs
By Cailin Heinze, VMD, MS, DACVN Assistant Professor of Nutrition, Cummings School of Veterinary Medicine
I’ve recently had several client questions about feeding vegetarian or vegan diets to their dogs. While many of us are moving towards higher protein, “grain-free” diets, some people are limiting the animal products in their own diets and wondering if they should do the same for their pets.
Adult dogs generally have high tolerance for carbohydrates, reasonably low protein requirements (similar to humans), and can utilize plant-sourced nutrients such as beta-carotene for vitamin A and vitamin D2 (ergocalciferol) for vitamin D at efficiencies similar to people. This means that vegetarian or vegan diets are certainly possible. The biggest concerns tend to be the amount and quality of protein as well as the overall quality control of the manufacturer.
While egg and dairy can both provide high quality protein in vegetarian diets, vegan diets pose more of a challenge. Soy protein can generally provide for dog’s protein and amino acids needs on its own, but other plant proteins require careful combinations or supplemental amino acids to fill in the gaps. Diets made from plant proteins tend to be limiting in the amino acid methionine, which is critical for protein synthesis but also for synthesis of taurine and carnitine in dogs. Dogs fed inappropriately formulated plant-protein diets can become taurine and carnitine deficient, so supplementation is recommended (although blood taurine levels can be monitored as well). Some commercial vegetarian/vegan diets contain both, others only taurine, and some neither.
Concerns have been raised about overall quality control in vegetarian and vegan diets. One recent study1 looked at amino acid concentrations in 24 commercial vegetarian and vegan diets and found that 6/24 (25%) diets did not meet Association of American Feed Control Officials (AAFCO) minimums for all amino acids (leucine, lysine, methionine, and tryptophan were the biggest issues). The amino acids weren’t the only quality control issues, either. Only 11/24 (46%) diets had a label that was compliant with all current pet food labeling regulations at the time of the study. Even worse, a follow-up study found lamb, beef, or pig DNA in 7/14 products labeled as vegetarian or vegan.2
For these reasons, I strongly encourage dog owners who are resolute about feeding a vegetarian or vegan diet to stick with the few veterinary therapeutic diets available that have been carefully formulated to meet nutrient needs for dog maintenance and are marketed for dogs with food sensitivities (e.g. Royal Canin Veterinary Diet Vegetarian canned and dry, Pro Plan Veterinary Diets HA Vegetarian). If clients are unwilling to feed these therapeutic diets, then sticking with the over-the-counter diets vegetarian/vegan diets from larger companies with a proven long-term track record is encouraged, rather than some of the newer or niche marketers. Especially for over-the-counter diets, I supplement carnitine and taurine and/or monitor blood taurine levels, and perform twice yearly chemistry panels and complete blood counts to look for potential issues.
Feeding a vegetarian or vegan diet to a growing puppy is strongly discouraged. There are no over-the-counter diets available that meet puppy nutrient needs and the risk of amino acid deficiencies and other serious nutritional issues in vegetarian and vegan diets is considerably higher than for an adult dog. If the puppy’s owner is completely unwilling to feed a more traditional diet until one year of age, the only vegetarian diet that I will recommend for puppies is Pro Plan Veterinary Diets HA, which has undergone feeding trials for growth and I have used successfully for puppy diet elimination trials.
More information on vegetarian diets for dogs can be found HERE.
1. Kanakubo K, Fascetti AJ, Larsen JA. Assessment of protein and amino acid concentrations and labeling adequacy of commercial vegetarian diets formulated for dogs and cats. J Am Vet Med Assoc 2015;247:385-392.
2. Kanakubo K, Fascetti AJ, Larsen JA. Determination of mammalian deoxyribonucleic acid (DNA) in commercial vegetarian and vegan diets for dogs and cats. J Anim Physiol Anim Nutr (Berl) 2017;101:70-74.