CAN DOGS BE VEGAN? VEGAN DOG FOOD STUDIES.
In the following article we point to a growing number of vegan dog food studies that increasingly conclude that not only can dogs be vegan, but should be.
No matter your reasons for exploring the option of feeding your dog vegan dog food, two questions will dominate. Will they like it? Is it healthy for them? To many, feeding a dog a meat-free diet is considered unnatural and depriving them of pleasure at mealtime.
The most important aspect of any diet, yours or your dog’s, is to ensure that you both get the correct balance of ALL the nutrients needed to thrive. Enjoying those meals is also a very important factor.
Let’s start with the unnatural and enjoyment question first.
Do Dogs Have a Preference for Meat?
A study published in the Journal of Ethology concluded that pups do not have an innate preference for meat and that any preference for meat is likely a learned behaviour.
A further study, published in Frontiers of Veterinary Science, found that dogs fed a novel diet, either meat or plant-based, experienced neophobia initially, however dogs did not show a preference for either the animal or vegetable ingredient-based diets.
Research published in Animal Feed Science and Technology found that that dogs demonstrated a preference for diets containing soybean meal, rather than diets containing poultry offal meal.
A 2021 study by Dr Andrew Knight published on PLOS One indicated that vegan pet foods are at least as palatable to dogs (and cats) as conventional meat-based kibble, wet food or raw meat diets.
Are Plant-based Ingredients Nutritionally Appropriate for Dogs?
As is highlighted in the Science of Nutrition, proteins, fats, carbohydrates, minerals, and vitamins – which they can get from either meat or plants. It is the balance, completeness and bioavailability of these nutrients which is most important for their thriving health.
The digestibility of any food your dog eats is vitally important. Digestion is the way your dog’s body breaks down food in their gut, extracting the macro and micronutrients and passing them into their bloodstream for use in maintaining, and improving, their health.
As a highly digestible food provides a higher proportion of absorbed nutrients than a less digestible food, digestibility provides an important measure of a food’s nutritional value and quality.
Can Dogs Digest Plant-based Ingredients?
Dogs’ diets and their physiology has developed in remarkably similar fashion to our own over more than 27,000 years. As they evolved from wolves to ‘domesticated’ dogs, and we moved from being hunters and gatherers to farmers some 5-7,000 years ago, so their genetic makeup evolved.
Evolutionary scientist Erik Axelsson and his colleagues at Uppsala University in Sweden discovered in this research piece published in 2013, that dogs have four to 30 copies of a gene, AMY2B, that allows them to digest starchy (plant-based) foods. Wolves typically only have two copies.
His colleague, Maja Arendt’s research published in 2014 in Animal Genetics, confirmed the ability of dogs to digest starchy, plant-based ingredients due to the drastic increase in copy numbers of the gene coding for pancreatic amylase, AMY2B. Their findings are corroborated by Morgane Ollivier’s 2016 research published in the Royal Society Publishing.
These previous studies surmised that dogs do not express salivary amylase, AMY1, however recent research, published in the National Library for Medicine, shows that several dog breeds do in fact express substantial amounts of this salivary amylase enzyme.
This means that as our dogs’ diets have changed so their genetic makeup has evolved, in similar fashion to humans’, to improve their ability to efficiently derive nutrients from plant-based foods.
Digestibility for Dogs of Grains and Other Starches.
As highlighted previously, the level of digestibility of ingredients in the food our dogs eat is important as it determines the extent to which nutrients are available for their overall health.
Research conducted by Murray and colleagues, published in 1999, looked at the digestibility of six high-starch flours as the main source of carbohydrate and included barley, corn, potato, rice, sorghum, and wheat. The findings, almost complete digestibility (>99%) for all ingredients.
A subsequent research piece by Carciofi and colleagues in 2008, on the digestibility of six starch sources - cassava flour, brewer's rice, corn, sorghum, peas or lentils - found that starch digestibility was >98%.
Cara Cargo-Froom, Anna Kate Shoveller and M.Z. Fan of University of Guelph published a study investigating the digestibility of minerals in animal and vegetable ingredient based dog food in 2017. Their findings - digestibility of the minerals Calcium, Phosphorous and Iron were greater in dogs fed diets that are largely vegetable based, and no different for Potassium, Copper and Zinc. Concluding that digestibility of endogenous minerals is similar, or greater, in dogs fed diets that are largely vegetable based.
In 2021, Amr Abd El-Wahab, Volker Wilke, Richard Grone and Christian Visscher published research on the nutrient digestibility of various vegetarian dog foods and concluded that the digestibility of organic matter, crude protein, crude fat and N-free extract were not affected for any of the diets.
Research conducted by the Department of Animal Sciences, University of Illinois into the ‘Use of Legumes and Yeast as Novel Dietary Protein Sources in Extruded Canine Diets’ concluded that inclusion of these novel, plant-based, protein sources (of chickpeas, lentils, peanut flour and yeast) showed no detrimental effects on nutrient digestibility or faecal characteristics and represent viable protein sources in canine diets that can produce beneficial shifts in faecal metabolites.
A further study, published on PLOS ONE in 2021, showed that digestibility of proteins, fats and starches were not different between chicken based and 100% plant-based foods.
Can Dogs Maintain Health and Thrive on a Plant-based Diet?
Possibly the question we all most want answered – ‘Will my dog be as healthy if they don’t have meat in their diet?’
Anecdotally the answer is unequivocally, yes.
One of the oldest lived dogs, Bramble, lived to the ripe old age of 27 years and 211 days and was fed on a vegan diet of lentils, textured vegetable protein, and brown rice, with some extra vegetables and fruit thrown in occasionally! Bramble was part of an 8-dog family, all fed a vegan diet, and in addition to her 27-year long life, three lived to be 19 and one lived to be 20!
There is a growing body of evidence that like us, our dogs’ health and longevity is best served by a diet that limits meat and favours plant based.
A 2009 study by Brown et al, An experimental meat-free diet maintained haematological characteristics in sprint-racing sled dogs, explored vegan diets in dogs that have some of the highest energy needs: sprint-racing huskies.
The study compared the health of twelve sled racing dogs -- six fed a nutritionally balanced meat-free diet, and the other six a commercial meat-based diet.
"Haematology results for all dogs, irrespective of diet, were within normal range throughout the study and the consulting veterinarian assessed all dogs to be in excellent physical condition." None of the dogs developed anaemia -- on the contrary, red blood cell counts and haemoglobin values increased significantly over time in both groups.
Subsequent research, Vegan nutrition of dogs and cats, by Pia-Gloria Semp at the University of Veterinary Medicine in Vienna was conducted with 174 dogs exclusively fed a vegan diet for a minimum of 6 months. The average duration of exclusively vegan fed dogs was 2.83years.
Physical examinations and clinical tests revealed those fed on a vegan diet did not display any irregularities connected to nutrition. Blood tests showed that all dogs who were examined had proteins within normal levels.
None of the tested parameters showed any difference or deviation compared to the results of dogs fed conventional meat-based food. Most importantly, no low levels of iron or vitamin B12 were detected in dogs fed vegan food.
A study, ‘Plant-based diets for dogs ’ investigating the nutritional adequacy of plant-based diets for dogs by Dodd et al from the Department of Clinical Studies, Ontario Veterinary College, University of Guelph concluded the following in their clinical summary
‘Dogs have dietary requirements for energy and essential nutrients, but they do not have a recognized requirement for animal-derived ingredients per se. In accordance with the current understanding of pet nutrition, any diet that meets or exceeds the minimum nutrient requirements of a dog for a specific life stage would be considered nutritionally sufficient for that animal, regardless of ingredients. However, special care must be taken when formulating plant-based diets to ensure that all nutrient requirements are met, particularly requirements for concentrations of total protein, methionine, taurine, DHA, vitamins A, D because these nutrients are typically obtained from animal-based ingredients.’
Madelaine Leitsberger and Professor Doctor Andrew Knight’ research piece, Vegetarian versus Meat-Based Diets for Companion Animals, published in 2016 concluded in summary, ‘a significant and growing body of population studies and cases suggest that cats and dogs may be successfully maintained on nutritionally sound vegetarian diets long-term, and indeed, may thrive. Such diets have been associated with benefits such as improved coat condition, allergy control, weight control, increased overall health and vitality, arthritis regression, diabetes regression’.
The largest study to date on the health effects of vegan vs meat based diets for dogs, Vegan versus meat-based dog food: Guardian-reported indicators of health, was published in 2022 by Andrew Knight et al.
The study assessed the diets of 2536 dogs of whom 1370 were fed a conventional meat based diet, 830 a raw meat diet and 336 a vegan diet and concluded, ‘Percentages of dogs in each dietary group considered to have suffered from health disorders were 49% (conventional meat), 43% (raw meat) and 36% (vegan). Significant evidence indicates that raw meat diets are often associated with dietary hazards, including nutritional deficiencies and imbalances, and pathogens. Accordingly, the pooled evidence to date indicates that the healthiest and least hazardous dietary choices for dogs, are nutritionally sound vegan diets.’
A research piece, Owner perception of health of North American dogs fed meat- or plant-based diets, published in 2022 by Sarah Dodd et al at the Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Canada.
Results showed that owners feeding plant-based diets to their dog reported fewer health disorders, specifically with respect to ocular or gastrointestinal and hepatic disorders. Dog longevity was reported to be greater for dogs fed plant-based diets. Owners feeding plant-based diets to their dogs relied less on veterinary associates for nutrition information, versus dog owners feeding meat-based diets.
The British Veterinary Association’s (BVA) view on feeding you dog a vegan/meat-free/plant-based diet is ‘While it is theoretically possible, the British Veterinary Association does not recommend giving a dog a vegetarian or a vegan diet as it is much easier to get the balance of essential nutrients wrong than to get it right.’ This is true but it is also very true of meat-based diet formulation.
A 2017 study by M. Davies et al of 177 popular meat-based (animal and fish) ‘complete’ pet foods sold in UK supermarkets, ranging from ‘supermarket own-brand’ food to ‘prescription/veterinary/therapeutic’ diets, concluded “This study highlights broad non-compliance of a range of popular pet foods sold in the UK with EU guidelines (94% and 61% of wet and dry foods, respectively). If fed exclusively and over an extended period, a number of these pet foods could impact the general health of companion animals”.Only 6% (6/97) of wet and 38% (30/80) of dry foods were fully compliant with EU petfood standards.
It is vital that our dog’s food contains all the nutrients it requires in the correct balance at a bare minimum and many meat-based foods have been found wanting.
They also add, ‘“Our advice to pet owners interested in exploring alternative diet options for their pets is to talk to their vet first, as any changes to a pet’s diet should only be undertaken under advice of a vet with in-depth nutritional knowledge.” The unfortunate fact is that most vets do not possess this in-depth nutritional knowledge. There are approximately 200,000 vets in the EU of whom less than a 100 are ECVCN (EBVS® European Specialist in Veterinary and Comparative Nutrition) registered – the qualification necessary to offer such in-depth nutritional knowledge.
The latest, and longest lasting, study on the effects of a vegan diet on dogs' health was published in 2023 by Annika Linde et al from WesternU College of Veterinary Medicine Office for Research and concluded that after a year of feeding a plant-based diet ' ....that clinically healthy adult dogs maintain health when fed a nutritionally complete, commercially available, plant-based diet with pea protein as a main ingredient over a twelve-month period.'
The study also found that when these meat-fed dogs joined the trial almost 50% were Vitamin D insufficient. During the 12 month trial the researchers found that vitamin D levels normalized in most dogs at six months (6 of 7 vitamin D insufficient dogs), and all dogs at 12 months all attributable to the plant-based dog food used for the study.
Additionally the dogs in the trial essential amino acid levels were met by the plant-based diet and that their L-carnitine and L-taurine levels increased from their meat-eating start of the study through their 12 month plant-based diet.
Finally the vegan dog study found that the body weight of dogs that switched to the plant-based diet remained stable, while body condition scores trended downwards in overweight/obese dogs.
The most recent endorsement that plant-based, or vegan diets, for dogs are appropriate was released in February 2023 by UK Pet Food (previously known as the Pet Food Manufacturers' Association or PFMA), whose members account for over 90% of the pet food market and are responsible for feeding the nation's wide range of pets.
The PFMA state ' Dogs are omnivorous carnivores which means that they can digest and utilise both animal- and plant-based ingredients. Their physiology can adapt to a well-balanced and carefully formulated vegetarian or vegan diet, given their individual circumstances.' Get their factsheet on vegan dog food.
However, possibly the most compelling ‘evidence’ that a vegan diet is nutritionally complete for our dogs is that many large meat-based dog food brands are now either investing in plant-based dog food companies or adding plant-based options to their product range to commercially capitalise on the increasing numbers of families looking to feed their dog a plant-based diet. Were these diets inadequate nutritionally in any way, this would not be the case.
Bonza vegan, plant-based dog food has been tested for nutritional completeness and balance at the Veterinary Faculty, Complutense University of Madrid, one of Europe’s leading veterinary institutions.
Plant-based. Environmentally friendly. Sustainable. Non-meat. Cruelty-free. Vegan Dog Food.