Is it OK to feed a dog a vegetarian diet? What about a vegan diet?
The answer is: it depends. Dogs have dietary requirements for energy and essential nutrients, not for specific ingredients. No single ingredient includes all the essential nutrients in the appropriate amounts, so complete and balanced diets are composed of multiple ingredients that may be animal-based or non-animal-based and are often supplemented with vitamins and minerals that may be synthetic or plant-derived.
Vegetarian or plant-based diets aim to avoid animal meat-based ingredients, while vegan diets aim to avoid all animal products, including ingredients like eggs and honey. Vegetarian diets have been successfully fed to dogs and there are medical situations in which a vegetarian diet may be recommended for a dog. However, in all cases, it is important to ensure that the diet is nutritionally adequate to support dogs’ overall health.
"While dogs do not have a specific requirement for animal-derived ingredients, some essential nutrients are found in higher amounts in animal products than in plant-based ingredients."
While dogs do not have a specific requirement for animal-derived ingredients, some essential nutrients are found in higher amounts in animal products than in plant-based ingredients. Thus, if feeding a plant-based diet, it is important that all essential nutrients are present in adequate amounts. Additionally, certain aspects of plants, such as the higher fiber content, may negatively impact the bioavailability of nutrients if the vegetarian diet is not properly designed.
How can I tell if a commercial vegetarian diet is nutritionally complete and balanced?
A few studies have evaluated the nutritional adequacy of vegetarian diets, and the results were mixed. Some studies suggest that dogs can maintain health by eating a plant-based diet; others point out nutritional deficiencies, including insufficient protein, insufficient essential nutrients (e.g., calcium, phosphorus, sodium, vitamin A, vitamin B12, taurine), trace element deficiencies, and an unbalanced calcium to phosphorus ratio.
For a diet to be considered complete and balanced per the Association of American Feed Control Officials (AAFCO) guidelines, it must meet the essential nutrient requirements of the target life stage and species and have a nutritional adequacy statement. A nutritional adequacy statement indicates that the diet was either formulated to meet your dog’s needs or it went through a feeding trial.
- If a diet is formulated for nutritional adequacy, it means that the food meets the dog’s nutritional requirements as calculated in a theoretical evaluation, but may fall short of those values when digested by the dog due to fiber content or other metabolic impacts.
- In a feeding trial, a diet is fed to the target group, which must maintain general health and weight throughout the trial. This test may better evaluate digestibility and bioavailability of a diet; however, feeding trials are not exhaustive. An adult maintenance diet that has undergone a feeding trial has been fed to 8 dogs for about 6 months, and the dogs have been monitored for general health. Some health parameters are evaluated to give an idea of whether the diet is adequate or inadequate, but blood tests are not comprehensive.
Be cautious when concluding a vegetarian diet is nutritionally adequate based on minimal evaluation. Neither method of nutritional testing is foolproof; diet formulation requires an understanding of the nutritional inputs from the ingredients as well as an understanding of the animal being fed. It is best to research the commercial vegetarian diet being fed to determine appropriateness: reach out to the company, ask who formulates the food and what their credentials are, ask what quality assurance steps are taken, and ask for a typical nutrient analysis of the finished product.
The World Small Animal Veterinary Association provides a Nutrition Toolkit and an informational handout (Guidelines on Selecting Pet Foods) that can help pet owners determine if the food they are interested in is likely a worthwhile product to feed their dog.
Can a home-cooked vegetarian diet be nutritionally complete and balanced?
Studies have evaluated the appropriateness of home-cooked diet recipes found online or in books and have consistently found nutrient deficiencies, whether the recipe was meat based or plant based. Even “complete and balanced" home-cooked diets provided by a Board-Certified Veterinary Nutritionist can be subject to “diet drift”, in which the person making the recipe “drifts” from recommendations and alters amounts or ingredients, rendering it no longer balanced.
"If you want to feed a home-cooked, vegetarian diet to your dog, discuss it with your veterinarian and engage the expertise of a Board-Certified Veterinary Nutritionist."
If you want to feed a home-cooked, vegetarian diet to your dog, discuss it with your veterinarian and engage the expertise of a Board-Certified Veterinary Nutritionist from the American College of Veterinary Nutrition (recently incorporated in the American College of Veterinary Internal Medicine – Nutrition subspecialty) or the European College of Veterinary and Comparative Nutrition.
Are there nutritional benefits for a dog fed a plant-based diet? Is it better for the environment?
Some may choose to feed a plant-based diet for religious, moral, or environmental reasons, or because of a perception of added health. Plants are excellent sources of fiber, which can help the large intestinal microbiome, and some plants have phytonutrients that provide benefits such as additional antioxidants. Plants also tend to be lower in calories, so with added fiber and fewer calories, plants may help your dog feel fuller while eating fewer calories.
There are some diseases that may benefit from nutritional management with a vegetarian diet. Some veterinary therapeutic diets are vegetarian, but not vegan, as they contain lanolin – a source of vitamin D3 and considered an animal product. Liver disease with hepatic encephalopathy is often treated using a plant-based diet, as are urate stones. If your dog has a health condition, talk to your veterinarian to determine if a vegetarian diet is appropriate for your dog.
Some people propose a plant-based diet for dogs as part of a smaller carbon footprint. If this is your goal, be sure to contact the food company directly to determine how their practices align with sustainability. Remember that packaging and shipping can have a significant impact on carbon output as well.
Are there nutritional concerns with feeding a vegetarian diet to a dog?
Some essential amino acids like methionine, taurine, and lysine are lower in plants than in animal tissues, so if a vegetarian diet is not properly formulated, it could be deficient in protein and amino acids.Some vitamins and minerals are also deficient or found in lower amounts in plants when compared to animal meats, including vitamins A, B12, and D, as well as the minerals calcium, phosphorus, potassium, and zinc. Thus, appropriate supplementation is necessary to ensure a plant-based diet is complete and balanced.
"High-fiber diets can impact taurine metabolism and may lead to increased taurine loss."
In addition, young growing dogs, particularly large-breed puppies, have increased nutrient requirements for the omega-3 fatty acid DHA. This fatty acid is essential for proper brain and vision development and is found mainly in marine sources such as fish and fish oils, but also in some marine algae. It is possible to provide vegetarian sources of DHA from marine algae, but as mentioned, it’s important to consult a pet nutrition expert to avoid nutritional deficiencies.
Lastly, plants have higher fiber content compared to animal products, which can provide good fuel for the microbiome, the healthy, helpful bacteria that live in the large intestine. However, fiber can also affect the digestibility of the diet. Increasing the amount of fiber can result in some nutrients being bound and not digested or used. High-fiber diets can impact taurine metabolism and may lead to increased taurine loss.
There has also been concern recently about potentially diet-related dilated cardiomyopathy (dr-DCM). While the definitive cause of dr-DCM has not been determined, there is concern that large inclusions of plant-based ingredients may play a role. Research is ongoing to try to determine the role of specific ingredient combinations on heart health.
Dogs are descended from wolves, so shouldn’t they eat meat-based diets?
Dogs are indeed descended from wolves, but many adaptations have occurred between ancestral dogs over 50,000 years ago and the chihuahuas, beagles, and Great Danes that we keep in our homes today.
Domesticated dogs have existed with humans for 10,000 to 30,000 years and are considered omnivores and are part of the order Carnivora (family Canidae). Many other animals belong to the order Carnivora, including obligate carnivores (i.e., cats, lions, tigers; family Felidae) and herbivores such as the giant panda (family Ailuropodidae), so animals in the Carnivora order are not necessarily strict carnivores.
Dogs’ genomes show distinct changes from their wolf ancestors that allow them to digest starches better, which has conferred a better ability to digest plant material. This adaptation also allows us to classify them as omnivores – able to eat both plants and meats.
"...a diet that is meat-based can just as easily be unbalanced and inappropriate if not properly made."
Regardless of what your dog eats, it is most important that the diet be complete and balanced for your dog’s life stage, be palatable, and highly digestible, as a diet that is meat-based can just as easily be unbalanced and inappropriate if not properly made.
Are any vegetables off limits?
There are some vegetables and other foods that should not be given as they have been shown to be toxic to pets. Foods that should be avoided include: alcohol, chocolate, macadamia nuts, garlic, onions, grapes, raisins, salty snack foods, and any food with xylitol artificial sweetener, such as some peanut butters.
Remember that some foods that are tasty to a dog may also be very high in calories, and those extra calories can add up very quickly. For example, sprayable cheese products and peanut butter are high in calories and should be used cautiously.
"If your dog has a health condition, discuss treats with your veterinarian
to ensure they are appropriate."
Also, if your dog has a diagnosed condition such as kidney disease, heart disease, or inflammatory bowel disease, some treats may not be appropriate. For dogs with kidney disease, low-phosphorus and low-protein treats are preferred (e.g, fruits and vegetables), while dogs with heart disease should avoid high-salt treats. If your dog has a health condition, discuss treats with your veterinarian to ensure they are appropriate.
What are some good vegetable and fruit treats?
Below is a table of fruit and vegetable ingredients that may be given as treats for dogs, with appropriate amounts and calories (kcal) they provide.
Remember to keep treats within 10% of total calories to prevent unbalancing the overall diet.
