HEALTH BENEFITS OF VEGAN DOG FOOD
By Michael W. Fox BVetMed, PhD, DSc, MRCVS
The dietary differences between wolves and dogs increased dramatically during the dog’s close association with humans, consuming less meat and animal produce and more grains and pulses, and with our transition for gatherer-hunter to agrarian settlements. Free-roaming community dogs adapted as scavengers which some believe was the portal through which less shy and more trusting wolves became domesticated.
Wolves were often cross-bred, I believe, with aboriginal dogs domesticated probably at least 30,000 years ago and far removed from any wolf ancestry, such as the Belgian Congo jungle hunters’ Basenji, and the New Guinea hunter’s Singing dog that spread around the world with human traffic and trade. In 2021, the genome of two Basenjis were assembled, which indicated that the Basenji fell within the Asian spitz group. The AMY2B gene produces an enzyme, amylase, that helps to digest starch. The wolf, the husky and the dingo possess only two copies of this gene, which provides evidence that they arose before the expansion of agriculture. The genomic study found that similarly, the basenji possesses only two copies of this gene. Other breeds have more of these genes which makes it easier to process dietary carbohydrates.
According to one genetic analysis, “High amylase activity in dogs is associated with a drastic increase in copy numbers of the gene coding for pancreatic amylase, AMY2B, that likely allowed dogs to thrive on a relatively starch-rich diet during early dog domestication. (See study, published in Journal World Prehistory, concludes that the food intake of dogs 3,500 years ago was conditioned by human activities, as it happens nowadays. In the Neolithic, human communities in the northwest of the Iberian Peninsula modified the nutrition of these carnivorous animals by introducing cereals and legumes in their diet. This practice remained the same in dogs from the Bronze Age and the First Iron Age but with innovations such as the presence of new cereals, particularly millet. ( See Aizuri, Aurora Grandal dʼAnglade et “Dogs that ate plants: changes in the canine diet during the late Bronze Age and the first Iron Age in the northeast Iberian Peninsula”, Journal World Prehistory, March, 2021. DOI: https://doi.org/10.1007/s10963-021-09153-9).
See also Pennisi E. 2016. How farming changed the dog. Science 360(6391): doi:10.1126/science.aal0353
According to Dr. Carol Beuchat’s survey, “Related carnivores like the wolf, coyote, and golden jackal have two copies of the AMY2B gene. The dogs with two or very few copies of the gene include the most primitive breeds and some of the spitzes (Dingo, Greenland Dog, Siberian Husky, Pug, Laika, etc). Among breeds that typically average more than 12 copies of the gene are the English Springer Spaniel, German Shepherd, Rottweiler, Border Collie, and whippet.” (Quote from https://www.instituteofcaninebiology.org/blog/a-key-genetic-innovation-in-dogs-diet). She concludes, “ So, what about all the hype about raw meat diets and grain-free kibble? They are fads, based on ideas instead of science. Clearly, dogs have adaptations for digestion of starch, just like we do, and they also love meat - again, just like we do. But grains have been a major component of the dog’s diet for thousands of years and the notion that the “natural” diet of the dog is a big, meaty bone is a myth. If anybody tries to convince you otherwise, demand to see some scientific evidence. You have the scientific sources available here that convincingly demonstrate otherwise.”
Although most dogs thus probably digest starch more efficiently than do wolves, AMY2B copy numbers vary widely within the dog population, and it is not clear how this variation affects the individual ability to handle starch nor how it affects dog health.” (Arendt M, Fall T, Lindblad-Toh K, Axelsson E. Amylase activity is associated with AMY2B copy numbers in dog: implications for dog domestication, diet and diabetes. Anim Genet. 2014 Oct;45(5):716-22. doi: 10.1111/age.12179. Epub 2014 Jun 28. PMID: 24975239; PMCID: PMC4329415.).
It is ironic that one US pet food manufacturer falsely claimed that its high cereal-content dog food was based on the “ancestral wolf diet” and was sued for false advertising and subsequently responded claiming 20% more meat content! Aside from reducing farmed animal suffering and the contribution of the livestock industry to climate change and loss of biodiversity, vegan dog foods are being developed that provide complete and balanced nutrition and evidence improved health benefits compared to conventional, highly processed dog foods, kibbe in particular. (For details see Big Kibble by Shawn Buckley and Dr. Oscar Chavez. St Martin’s Press NY.)
Veterinarian Dr.Mike Davies from the University of Nottingham, England, reported the benefits of a vegan diet for dog’s health and overall well-being. “The vegan food was acceptable (palatable), and appetite and body weight were not adversely affected. Changes, including improvements, were reported in the following areas: body condition score (BCS), activity, faecal consistency, faecal colour, frequency of defaecation, flatus frequency, flatus antisocial smell, coat glossiness, scales in haircoat (dandruff), redness of the skin (erythema, inflammation), crusting of the external ear canals (otitis externa), itchiness (scratching; pruritus), anxiety, aggressive behaviour and coprophagia.” (Mike Davies. Reported Health Benefits of a Vegan Dog Food – a Likert Scale-type Survey of 100 Guardians. Archives of Clinical and Biomedical Research 6 (2022): 889-905.).
See also Knight A, Huang E, Rai N, Brown H (2022). Vegan versus meat-based dog food: Guardian-reported indicators of health. PLoS ONE 17(4): e0265662. https://doi.org/10.1371/journal.pone.0265662.
According to Prof. Knight “There are now eight studies or veterinary masters theses, examining health outcomes in dogs maintained on vegan or vegetarian diets. Seven studies now support the use of these diets. The weight of evidence now overwhelmingly supports the use of nutritionally sound vegan dog food.” ( https://vegan-dogfood.co.uk/2022/10/27/more-published-evidence-by-top-vet-nutritionist/).
In one valuable study, “dogs consuming vegan diets had lower fecal dry matter percentages, lower fecal phenol and indole concentrations, and higher fecal short-chain fatty acid concentrations than those consuming the extruded diet. Fecal bacterial alpha and beta diversities were not different among diets, but dogs consuming vegan diets had altered relative abundances of nearly 20 bacterial genera when compared with those consuming the extruded diet. In conclusion, the mildly-cooked human-grade vegan dog foods tested in this study performed well, resulting in desirable fecal characteristics, ATTD, (apparent total digestibility) and serum chemistries. The vegan diets tested also led to positive changes to serum lipids and fecal metabolites, and interesting changes to the fecal microbial community.”( Leah J Roberts, Patricia M Oba, Kelly S Swanson, Apparent Total Tract Macronutrient Digestibility of Mildly-Cooked Human-Grade Vegan Dog Foods and Their Effects on the Blood Metabolites and Fecal Characteristics, Microbiota, and Metabolites of Adult Dogs, Journal of Animal Science, 2023; skad093, https://doi.org/10.1093/jas/skad093).
Additional potential health benefits for dogs, and for their owners in savings on veterinary diagnostics and treatments, of vegan diets would be in the prevention and reduced incidence of several diseases. These include cancer, kidney, heart, liver, and pancreatic disease; chronic inflammatory diseases such as inflammatory bowel disease and arthritis; obesity and its harmful consequences developing secondarily due to reduced physical activity associated with arthritis associated with neutering; food allergies and intolerance, (often due to eggs, dairy products, fish, beef, and chicken) leading to irritable bowel issues, “leaky gut” and skin problems. Notable behavioral changes have been reported including less anxiety, irritability, aggression and greater overall calmness.
The Plant-Powered Dog: Unleash the healing powers of a whole-food plant-based diet to help your canine companion enjoy a healthier, longer life by Diana Laverdure-Dunetz, MS, with contributor W. Jean Dodds, DVM, (Dogwise Publishing, January 2023) demonstrates that a well-balanced plant-based diet is the healthiest and safest for modern companion dogs, drawing on research in canine evolution, genomics and epigenetics to dispel the myth that dogs are carnivores. It showcases the best food sources for vegan dogs; teaches readers to prepare nutritionally sound vegan dog food recipes; and offers plant-based solutions to common canine chronic diseases.
I strongly advise dog owners whose canine companions are on various costly, veterinary-prescribed “special diets” to discuss with their veterinarians transitioning their dogs onto a good vegan diet, inherently hypoallergenic, anti-inflammatory and with an organic fiber content beneficial to gut bacteria producing nutritive, immune system-supporting short-chain fatty acids and calming, stress-alleviating serotonin, and another neurotransmitter, Gamma-Aminobutyric Acid (GABA). This regulates and improves mood because it helps to calm the nervous system and switch off stress reactions.
For a critical appraisal of these prescription diets see the book Not Fit for a Dog by Drs. Michael W. Fox and Elizabeth Hodgkins and Prof. Marion E. Smart.
All vegan diets should be tested for glyphosate herbicide residues, insecticides, heavy metals and aflatoxin. Lentils and other pulses must be soaked and rinsed before inclusion to remove pro-inflammatory lectins (glutens and gliadins). Some breeds may be intolerant or allergic to wheat in their diets. No ingredients should be subjected to high-heat processing ( as is most conventional dog kibble) because of the Maillard reaction resulting in the creation of acrylamides associated with inflammation, ageing, heart disease, kidney failure and cognitive impairment.
The problems of bacterial endotoxins and antibiotic resistant bacteria from contaminated animal ingredients would be minimalized by vegan diets for dogs and humans.
Vegan dog foods with slow-cooked and dehydrated ingredients to avoid this Maillard reaction should be sprinkled with warm water before feeding to enhance palatability and moisture content. I also add a little grated carrot, crushed blueberries or sprouted mung beans to our dog’s Earth Animal Wisdom dry dog food since some raw foods (not meat and bones!) are of nutritional and microbiome benefit. The more diverse the dietary ingredients, the more diverse and healthier the microbiome.
A biologically available source of omega 3 fatty acids is essential in all vegan dog food formulations. Plant-derived omega-3s (as from flax, chia, and hemp seeds) come in the form of alpha-linolenic acid (ALA)—which is the only essential omega-3 fatty acid. Our bodies cannot synthesize it, so we must consume ALA through our diets. The body naturally converts ALA into longer chain omega-3 fatty acids, docosahexaenoic acid (DHA)—which is important for brain health—and eicosapentaenoic acid (EPA). But most dogs and all cats cannot make this conversion, so they need either fish oil that contains both DHA and EPA or be provided with algae rich in DHA and EPA that fish consume.
Dogs should be transitioned gradually from their regular food to a new vegan diet to allow their gut bacteria (the microbiome) to adjust, along with associated digestive processes. Putting 10% of the vegan food in 90% of the regular, then daily steps of adding 10% of the new and removing 10% of the remaining 90%/80%/70% and so on over a period of 10 days should suffice. Small breeds, puppies and old dogs may benefit from the addition of digestive enzymes as provided by papaya and pineapple, putting 1 tablespoon of either (unsweetened) per 50 lb body weight in each meal, and be fed two-three small meals daily only after exercise. All dogs should be weighed every 4-6 weeks and fed more or less to maintain optimal weight and condition, ideally with veterinary evaluation.