The biggest challenge dog parents face when switching their dogs to a vegan diet, is acceptance. Many people are misinformed or just refuse to accept that a dog can thrive on a vegan diet. There are numerous marketing tactics by dog food companies fueling the common misconception among dog owners that dogs are obligate carnivores and require a diet comprised mostly of meat. This is simply not true. It is true that dogs belong to the order Carnivora, but unlike cats, who are obligate carnivores, dogs are biologically omnivores and can thrive on a plant-based diet.
I have done extensive research on domestic dogs, including their evolution, behavior, physiology, and diet. One of the areas I spent significant time on pertains to their diets and getting to the bottom of many myths and misconceptions. When I switched my dogs to a vegetarian diet, I wanted to be as informed as I possibly could on the topic.
Evolution of the Domestic Dog
Dogs and grey wolves diverged from an extinct wolf species at least 30,000 to 40,000 years ago, though DNA analysis published in 1997 suggests that the divergence of dogs from wolves may have begun about 130,000 years ago; predating permanent human settlements and agriculture. These early wolves adapted to human society and lived side by side for tens of thousands of years; co-evolving with humans. Domestication of the dog stands as one of the most important and remarkable events in human’s evolutionary journey. To really understand the domestic dog, it is important to know a little about where they came from and how they came to be the amazing animal we know and love today.
Domesticated dogs are far removed from their wolf ancestors and show significant genetic divergence as well. The domestication of the dog resulted in morphological changes including a reduction in size, smaller skulls, shorter and wider bodies, changes in the shape of the mandible, crowding of teeth, a general reduction in tooth size, and more rounded forward-facing eyes.
Beyond the range of shapes and sizes, they have substantial differences in their DNA as well, such as their ability to digest a wider range of foods than their wolf cousins. New genetic evidence suggests that dogs have been enjoying a variety of food scraps from humans since the earliest days of living together, even adapting to changes in the human diet over time.
When dogs were first domesticated, their wolf-like ancestor would have primarily scavenged meat scraps from hunter gatherers, but over time this transitioned to include cooked foods, including not just meat, but a variety of other foods. Modern dogs are able to digest starch and grains far more efficiently than wolves, along with a variety of other foods, including vegetables and fruits. This has allowed the domestic dog to thrive alongside their human companions and adapt to the various foods available at any given time.
Researchers in Sweden found that the dog genome contained increased amounts of the gene AMY2B, which codes for the production of the enzyme amylase, a protein that starts the breakdown of starch in the intestine. Dogs have up to 30 copies of the gene for amylase. Wolves have only two copies, one on each chromosome. According to researchers, the findings show how the introduction of farming directly affected the evolution of dogs and their physiology, allowing them to adapt to a diet containing starches, such as grains, beans, and potatoes. They also found that domestic dogs had a version of another enzyme important in starch digestion; maltose, which was more similar to the type found in herbivores, such as cows, and omnivores, such as rats, than to wolves.
The adaptations of dogs to a more plant-based diet is not just evident at the enzyme level. Like any other animal, dogs rely on their gut bacteria to help them digest food efficiently. Only recently, it was shown that the gut microbiome of the domestic dog is very different to that of wolves. Domestic dogs have more evidence of bacteria that breaks down carbohydrates and also produce amino acids normally sourced from meat.
Dietary Physiology of the Domestic Dog
People often mistakenly think that domestic dogs are just like wolves and though they are closely related, the changes dogs have gone through over the past tens of thousands of years are substantial. The shift in the dog’s diet parallels that of humans through their shared evolutionary journey.
It is also important to note that though wolves eat a primarily meat-based diet, they are also omnivores and studies in Yellowstone Park have shown that most wolves consume quantities of plant matter, including grasses and berries, at various times of the year. However, the digestive system of domestic dogs is far more efficient at processing and extracting nutrients from a variety of plant matter than their wolf cousins, which has allowed them to thrive alongside their human companions. Feeding a dog like a wolf is ignoring tens of thousands of years of evolutionary changes and adaptations. Domestic dogs are not “natural” they have been shaped over thousands of years by humans. Eating raw meat is no more “natural” to them than it is to us.
Nutritional Needs of the Domestic Dog
What are the nutritional needs of the domestic dog? This varies, since there are breed variations in metabolism and nutrient requirements and it is important to take into consideration the lifestyle and age of the dog. Generally nutritional guidelines for domestic dogs have been developed by the Association of American Feed Control Officials (AAFCO). These are only guidelines however, and individual needs should be considered. Dog breeds that evolved in certain locations, such as Arctic breeds for example may have adapted to specialized diets that are common in their place of origin. Some breeds may not digest grains as well as others, some breeds are lactose tolerant, while others are not, some dogs are adapted to higher fat diet, working dogs require different ratios of nutrients compared to sedentary dogs, older dogs require different ratios of nutrients than puppies, etc.
Food Allergies and Intolerances in Dogs
It usually surprises people to know that the top food allergens for dogs are meat and dairy. Food allergies in dogs manifest symptoms similar to human allergies, such as skin irritations including dry and itchy skin, rashes, loss of fur, or GI issues including loose stool, constipation, gas, or vomiting.
Common foods that cause allergic reactions in dogs:
Often when a dog is diagnosed with food allergies or intolerances, a vegetarian diet is recommended and this has resulted in an increase in the availability of vegetarian and vegan diets on the market. A vegetarian diet for a dog with food allergies is often accepted as a necessary modification to a dog’s diet to manage their allergies and improve their health, but people are still resistant to the idea that it can be a beneficial diet for dogs, period.
Other than food allergens, there are a number of foods that should not be fed to dogs, some of which can be toxic. For more details on these foods, check out Food Allergens and Toxins. Always speak to your veterinarian if you suspect your dog is suffering from a food allergy.
Can Dogs Thrive on a Vegan Diet?
The simple answer is yes! Dogs have evolved alongside humans for tens of thousands of years and are physiologically omnivores, which allows them to derive nutrients from both animal and plant matter and like humans, they can thrive on a balanced vegan diet.
One of the most common questions vegans get is “Where do you get your protein?”, so it certainly comes up for vegan dogs as well. When we talk about protein, what we are really referring to are amino acids; the building blocks of protein. There are 21 protein building amino acids and in humans 12 of these are produced naturally by the body, and 9 are essential amino acids that must be obtained from food. The canine body has the ability to produce 11 of these amino acids. In fact, dogs require the same 9 essential amino acids as we do, with the exception of one extra, Arginine. There are many plant-based sources for Arginine however, including pumpkin seeds, soybeans, peanuts, chickpeas, and lentils. Like humans, dogs can get all the amino acids they need from a plant-based diet, including easily digestible and healthy protein sources such as peas, lentils, and quinoa.
10 Essential Amino Acids for Dogs:
Keep in mind that with any diet, whether it’s meat-based or vegan, it needs to be balanced. Not all vegan diets are created equal. Be sure to check ingredients and nutrition levels. Any diet, whether vegan or meat-based, should be nutritionally complete and meet AAFCO guidelines to ensure you’re not missing out on any nutrients. Look for wholesome ingredients, including a good protein source such as lentils or peas, and whole vegetables, fruits, and grains. Only feed commercial vegan and vegetarian diets. Homemade diets may not be appropriately balanced. Commercial diets must meet the requirements for AAFCO (Association of American Feed Control Officials) compliance. It is a good idea to consult with a veterinary nutritionist in order make sure that the vegan or vegetarian diet fulfills the necessary requirements for your dog based on their breed, age, lifestyle, etc. Pay attention to your dog and be aware of any changes in their health or behavior. Schedule regular vet visits and routine bloodwork.
Benefits of a Vegan Diet for Dogs
Just like with humans, a vegan diet can be very beneficial for dogs. A vegan diet can help prevent obesity, improve digestion, increase energy, lower the risk of allergies, reduce inflammation, reduce bad breath, and improve skin and coat.
Many fruits and vegetables act as natural anti-inflammatories and antioxidants, including strawberries, papaya, raspberries, and particularly blueberries. Many vegetables, including kale, spinach, carrots, broccoli, cauliflower, squash, and bell peppers are packed with vitamins and are a great source of antioxidants with anti-inflammatory properties as well. Pumpkin and sweet potato are powerful antioxidants, immune system boosters, and aid in digestion. Quinoa is one of those super foods, not only for people, but also for dogs. It is a good source of fiber, folate, magnesium, iron, phosphorous and many phytochemicals. Quinoa is also a potent antioxidant and can reduce the risk of diabetes and has the added bonus of being a complete protein (provides all essential amino acids). Another super food that provides all essential amino acids is nutritional yeast. The health benefits of nutritional yeast are abundant, including healthier skin, hair, nails, boosted immune system, and increased energy. Plus it is easy to add nutritional yeast to your dog’s diet; just sprinkle a little on their food.
Recalls, Raw Meat, and Health Risks
Many vets believe that the increase in rates of cancers, kidney failure, and other degenerative diseases in dogs may be due to the harmful ingredients found in many commercial meat-based dog foods. The majority of meat used for commercial dog foods comes from factory farms, where livestock are injected with growth hormones and antibiotics, fed sub-optimal diets, and live in unhygienic conditions. Dog food manufacturers use 4-D meat. 4-D meat refers to meat from animals that are “dead, dying, disabled, or diseased,” which the FDA states is “a potential health hazard to the animals that consume it and to the people who handle it.” According to Dog Food Advisor, ingredients can also include “slaughterhouse waste and spoiled supermarket meats — even diseased or dying cattle — or dead zoo animals.” These byproducts are deemed unfit for human consumption and include beaks, skin, bones, feet, tendons, brains, intestines, feathers, reproductive organs, tumors, underdeveloped eggs, etc.
Often people think that a raw meat diet is the answer, but that couldn’t be farther from the truth. Feeding your dog a raw meat diet, puts them and your family at risk of food-borne illnesses like Salmonella, E. coli, and Listeria monocytogenes. Raw diets are also very poorly regulated and have a higher impact on the environment. A diet of raw meat and bones is usually deficient in essential vitamins and minerals and often contain higher than required levels of protein, which can lead to kidney disease, chronic dehydration, and obesity. It is also virtually impossible to maintain a proper calcium/phosphorous ratio with a diet consisting mostly of meat. When this ratio is out of balance, disruptions in bone growth or kidney damage can occur. Not to mention the many dangers of eating raw or even cooked bones. There is no evidence that raw meat-based diets, or RMBDs, are healthier than conventional dry or canned dog foods. There is however research published in Vet Record (see resources below) that shows these diets could pose a significant threat to both animal and human health.
The American Veterinary Medical Foundation maintains a database of dog food recalls. In the month of February 2018 alone for example, 38 products were recalled for contamination, primarily from either pentobarbital (a euthanasia drug) or Salmonella contamination. Adverse reactions to these contaminants include, fever, shock, lethargy, diarrhea, vomiting, loss of appetite, weight loss, weakness, depression, dehydration, skin disease, mucus in stool, fast heart rate, swollen lymph nodes, and even death.
My Veterinarian says Vegan Diets are Not Safe
I hear it all the time from people; “dogs need meat” or “dogs are carnivores,”; neither of those are true, but when you hear it from a vet, you may feel compelled to believe it without question. This can be a frustrating challenge. Some vets have a negative attitude about vegan diets for dogs, but this is only because most vets are not educated in nutrition or alternative diets for dogs, or they base their opinions on misinformation, such as “dogs are carnivores”. The truth of the matter is that most veterinarians receive very little education on the nutritional needs of dogs and much of their knowledge comes from sponsoring brands like Hills, Purina, or Royal Canin, who want veterinarians to sell their products and even provide free food for the veterinarians’ own dogs. However, this is not the case for all veterinarians and many have become better informed and support and even recommend a complete and balanced vegan diet for dogs.
The Bottom Line
There are a variety of reasons for people to choose a vegan diet for their dogs; they may be ethical vegans, or want to improve their dog’s health, they may have concerns for the environment, their choice may be based on political, cultural or religious ideals, or they may just want to manage their dog’s allergies. Whatever the reason, the choice is entirely yours. If you do choose a vegan diet, be sure to consult with your veterinarian and gradually make the transition over a week or so. What we all want for our dogs is happiness, longevity, good health, ideal nutrition, good body condition, and avoidance of trauma and disease.
If you do decide to switch your dog’s food to a plant-based diet, it’s important to ensure that the diet you choose is nutritionally complete and balanced. It is important with any diet, that the food meets all your dog’s nutritional needs. A vegan diet can provide a wealth of benefits to your dog but it can also be harmful if it is lacking important nutrients or supplements and doesn’t meet the recommended AFFCO guidelines. Though I have done a lot of research on the subject, I don’t have all the answers, so be sure to do your own research and always consult with a veterinarian.
Abrantes, R. 2005. The Evolution of Canine Social Behavior. Wakan Tanka Publishers, 2nd Ed.
Brevitz, B. D.V.M. 2009. The Complete Healthy Dog Handbook: The Definitive Guide to Keeping Your Pet Happy, Healthy & Active. Workman Publishing, NY.
Coppinger, R. and Coppinger, L. 2001. Dogs: A New Understanding of Canine Origin, Behavior, and Evolution. The University of Chicago Press.
ReBow, V. and Dune, J. 1998-2005. Vegetarian Dogs: Toward a World Without Exploitation. LiveArt. http://vegetariandogs.com/
The information contained in this post is not meant as a substitute for veterinary care. Please consult a qualified veterinarian with any concerns or advice for your particular situation.