Researchers at the Western University of Health Sciences, in California, USA confirmed ‘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.’
A significant amount of vitriol surrounds the feeding of plant-based, vegan food to dogs from those who consider it unnatural and cruel. Typical responses on social media include ‘ A carnivores food should be majority meat. If you don’t want to feed it meat get a rabbit.’
First it must be said that dogs are omnivores and have been evolving from their ancestors, wolves, for the past 27,000 years in remarkably similar fashion to their human guardians. Physiologically they have developed the amylase gene, the gene responsible for digesting carbohydrates. Dogs have evolved further and are now producing salivary amylase, as we do, which further assists in the carbohydrate digestion process. (1)
The British Veterinary Association (BVA) has, until recently, adopted an unequivocal position on both the validity, and ethics, of feeding dogs a vegan diet – ‘Not Recommended’.
On the ethics, The BVA president, Justine Shotton, had this to say in late 2021 ‘ “Under the UK’s animal welfare acts, pet owners have a duty of care towards their pet to ensure that their five welfare needs, including an appropriate diet, are met. Owners could potentially be prosecuted under the provisions laid out by this Act for causing deliberate harm and suffering to any animal by failing to meet its welfare needs despite expert advice.” (2)
On the question of completeness and balance she further opined ‘“Meat contains vital vitamins and nutrients needed by cats and dogs. Although we would not recommend it, it is theoretically possible to feed a dog a vegetarian diet, but owners would need to take expert advice to avoid dietary deficiencies and associated disease, as it is much easier to get the balance of nutrients wrong than to get it right. A dog on a vegan diet may also need synthetic supplementation.’
Completeness and balance in a dog’s food, and diet, is a must irrespective of whether that dog’s diet is meat or plant-based. Great care needs to be, and is, taken by companies who produce food for dogs irrespective of the source of protein.
There have been many examples of recalls of meat-based dog food produced by large brands for deficiencies or excesses, as well as for the presence of toxic bacteria, that could, or would, prove potentially harmful to dogs if continued feeding occurred (3, 4, 5)
There would be very few, if any meat or fish based dog foods on the market that are not supplemented with vitamins and minerals. Some of this is due to the degradation and loss of these vital nutrients during high temperature processing as well as during storage.
The simple truth is it is the quality, and balance, of ingredients, their bioavailability, the formulation and processing method that need to be taken into account when any dog food, vegan, meat or fish is produced. A dog fed on meat alone would not survive very long – firstly our dogs, like us need fibre, and this only comes from plant-based sources. Meat has no dietary fibre and no calcium and is deficient in many essential vitamins and minerals. (6)
Responding to a large scale study (2,536 dogs) study conducted by Dr Andrew Knight and published in 2022 which concluded ‘..the pooled evidence to date indicates that the healthiest and least hazardous dietary choices for dogs, are nutritionally sound vegan diets.’, Dr Shotton commented “There is currently a lack of robust large-scale data mapping the health consequences of feeding a vegan diet to dogs over their lifetimes, so we look forward to seeing further research on whether non-animal protein sources can meet a dog’s dietary requirements throughout life.
“We know there are limitations to owner-reported data, which can only provide one aspect of the picture, so we’re also keen to see future studies assessing clinical data in order to build a more holistic view of the health impact of vegan diets on dogs.”
Whilst there is a significant, and growing, body of anecdotal evidence on the viability, and healthfulness, of vegan diets for dogs this is understandably not considered sufficient for the BVA who “As an evidence-based organisation, the BVA will continue to follow and assess all emerging evidence regarding vegan, as well as other, novel diets.”
So to the most recent research, a year long study of previously meat fed dogs who were transitioned to, and fed, a vegan, 100% plant-based diet for 12 months maintained good health.
Their findings indicated:
- That almost half (7 of 15) of the dogs presented with insufficient levels of 25-hydroxyvitamin D at baseline. In other words 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.
- That study diet provided all essential AAs exogenously. Additionally, L-taurine (plasma) and L-carnitine (serum) levels showed a statistically non-significant increase in these nutrients when comparing baseline to endpoint values. In other words the dogs on 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.
- The researchers also documented 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. Plant-based nutrition is known to reduce body fat in people through various mechanisms, including the lower caloric density of many whole plant foods, impact on energy balance through gut microbiome modulation, increased post-prandial metabolism (diet-induced thermogenesis), etc.
- On Cobalamin (vitamin B12) and folate (vitamin B9), with levels measured at 0, 6 and 12 months, the study found that cobalamin measured within the normal reference interval at all three time points. In the case of folate, on commencement of the trial 6 of the 15 meat-fed dogs were folate insufficient with the number halving to 3 at the conclusion of the trial in month 12.
It is important from a scientific point of view to note that this study design goes far beyond AAFCO feeding trial guidelines, considered the ‘gold’ standard for evaluating the nutritional safety of the food. These physiological parameters are assessed to ensure all animals participating in the trial remain healthy and in good condition and using the subsequent evaluation to substantiate complete and balance pet food claims and make these results available to vets and consumers.
The AAFCO feeding trials recommend a minimum study period of six months and eight dogs with the health exams performed by a licensed veterinarian and assessment of four blood parameters, including haematocrit, haemoglobin, albumin, and alkaline phosphatase.
This against the current study using 15 dogs for a period of 12 months to evaluate the nutritional safety and health and condition of the dogs fed a vegan diet.
I have no doubt the response from the veterinary bodies will be along the lines of ‘ this being a single study, based on a single food, that is not ‘lifelong’ we need to see more evidence to demonstrate the validity of vegan diets for dogs.’
To those researchers who conduct these studies whether it is for the health of our dogs, animal welfare or environmental sustainability reasons thank you for shining a light.
So finally to the sustainability issue of feeding our dogs meat-based food versus plant-based dog food.
Animal agriculture is responsible for 16.5-18.5% of greenhouse gas emissions, and 90% of deforestation according to the FAO (7). Scientific opinion is now largely without doubt that the single biggest change we can, and must, make to our lifestyles to mitigate climate change is to eat less meat and a greater variety of plant-based foods beyond the monocrops – corn, wheat, soy and rice (a huge emitter of methane in its own right – 2nd only to ruminants.)
Studies on the consumption of meat by our pets estimate that they consume as much as 20% of all animal product.
According to the BVA ‘The meat used is often that which would never end up in the human food chain in this country, as many consumers don’t like to eat those parts of the animals – for example, tripe, pig’s trotters, udders and chicken feet. Pet food is a useful way to use this nutrient-dense food without it being wasted, which is important both from a sustainability and an ethical perspective.’
Their suggestion for dog owners looking to adopt a more sustainable approach – ‘There are other ways in which pet owners can exercise sustainable and ethical choices too – for example, by using biodegradable poo-bags, giving play and attention rather than plastic toys, discussing the best parasite treatment plans with their vet, and making better choices for animal welfare at supermarket checkouts for their own food …’
Examining these two viewpoints it is difficult not to feel somewhat despondent and disappointed.
Firstly, in the face of mounting global food insecurity, and a population predicted to reach 9 billion by 2050 it is difficult to imagine that our culinary squeamishness could possibly be elevated above the immediate need to reduce the emissions necessary to protect those most at risk from climate change and the resulting food, and water, shortages they face. There are many millions, if not hundreds of millions, who find tripe, pigs, trotters, chicken’s feet, tongue, brains, kidney and livers delicacies. There are countless millions who cannot afford meat of any kind, who would readily consume these animal by products (ABP) as they are referred to.
To infer that using biodegradable poo-bags, eschewing plastic toys and discussing your pet’s parasite treatment plan offers an alternative to altering their diet as a route to meaningful sustainability would seem disingenuous at best.
It is interesting that the petfood industry has railed so strongly against both US and EU plans to recategorise rendered animal fats category 3, allowing for the the inclusion of Category 3 in the biofuels targets to decarbonise the transport sector – another large emitter.
This will place the petfood industry in direct competition with the transport sector for a currently undervalued, and declining, resource with resulting increases in price threatening their access to these cheap ingredients.
We must accept that feeding our dogs meat-based food versus plant-based food is not a binary option.
More so now that a growing body of scientific evidence shows us that our dogs are not just sustained by plant-based diets but also it seems healthier.
Our hope is that the BVA heeds this growing body of evidence and acknowledges that vegan diets for dogs are not ‘unethical’ or dangerous if formulated by expert nutritionists and produced by reputable companies.
This will salve the conscience, and assuage the guilt, of those looking to make a sustainable feeding decision for their dogs who rely on veterinary opinion, which to date has left them in little doubt of their viewpoint.
For the health of our dogs and the planet it is time to stop demonising vegan dog food.
