Although biologically omnivores, dogs are often labelled as carnivores. Almost never are they considered vegetarians. Yet vegan pet foods (excluding any animal products) are increasingly being developed for environmental and animal welfare reasons. And now a study just published in the British Journal of Nutrition has demonstrated good health outcomes in dogs fed vegan diets. Dr Sarah Dodd and other veterinary nutritional specialists from Canada’s Ontario Veterinary College found that 31 dogs fed vegan diets for three months had health outcomes as good as 30 fed meat-based diets.
The dogs were comprehensively assessed via veterinary examinations, blood and urine tests, and X-rays. Vitamin D plays a key role in regulating bodily calcium levels, and in maintaining good bone health. It is normally sourced from animals, and the effectiveness of vegan vitamin D had been uncertain. However, Dodd’s research group showed that blood levels of vitamin D and calcium did not change in dogs fed entirely vegan diets. X-rays confirmed that bone mineral content and density were unaffected, and other health parameters were also maintained.
This is the latest among 10 studies that have now confirmed good health outcomes in dogs fed vegan diets. Some are very large-scale studies, following an explosion of recent interest in this field. In 2002, Dodd and her colleagues analysed the lifespans of 1,201 dogs, finding that dogs fed vegan diets lived 1.5 years longer, on average. Said Andrew Knight, a veterinary Professor of Animal Welfare, “That equates to around an extra decade, at the end of a human lifespan. And as well as longer lives, dogs fed vegan diets seem to enjoy better quality of life, because rates of key illnesses impacting life quality, consistently appear lower.” In 2002 Prof. Knight and colleagues also studied health outcomes in 2,536 dogs and concluded that the healthiest and least hazardous diets for dogs were nutritionally sound vegan diets.
Even cats appear to benefit from vegan diets, provided these are nutritionally-sound. At least three studies have confirmed positive health findings in cats. A 2023 study of 1,369 cats by Knight and colleagues calculated reductions in risks of a broad range of illness indicators, for cats fed vegan diets. Their detailed analysis of feeding behaviour of 2,308 dogs and 1,135 cats also found that average pets appeared to enjoy vegan meals, as much as those based on meat.
Knight commented that these new studies had opened the door to major environmental benefits offered by vegan pet food. His 2023 study calculated that vegan pet food could save enormous quantities of greenhouse gases, land, and water and that resultant food energy savings could feed billions of additional people globally. Another landmark study also recently identified major climate benefits associated with plant-based diets.
However, Knight cautioned that, “to safeguard the health of our pets, it is important we feed only commercial vegan pet foods labelled as nutritionally complete, produced by reputable companies with good standards.”
Veterinary Professor of Animal Welfare