Vegan pets: what does the data say?

Commercially available vegan kibbles appear just as likely to meet canine nutritional needs as meat-based kibbles – that’s the conclusion of a study by the UK’s University of Nottingham published last year.

Recent nutritional analyses

The study, published in the journal PLOS One, found the nutritional composition of six plant-based dog kibbles was comparable to that of 25 meat-based foods. The plant-based foods were, however, found to be lower in iodine and B vitamins.

Half of all foods tested – both meat- and plant- based – were deficient in one or more amino acid. Less than a quarter of the tested kibbles contained adequate B vitamins, and just 16% met all mineral recommendations, according to the study.

Lead author Rebecca Brociek notes that the results showed a fairly even playing field between meat-based and plant-based kibbles. “I thought given what people say about plant-based diets, that the meat-based ones would be kind of perfect and hit all the nutrient minimums, and that all the plant-based ones would be deficient in something,” she says.

Previously, an analysis by Brazilian researchers, published in PLOS One in January 2020, reported deficiencies in calcium, potassium, sodium, methionine and arginine in four vegan pet foods – three for dogs and one for cats. Brociek notes that the Brazilian study lacked a meat-based comparison group, making deviations appear unique to vegan foods when they are common across all formulations. For example, the UK study identified three meat-based pet foods that did not contain adequate zinc.

Researchers have yet to definitively conclude why vegan pet foods consistently had lower levels of iodine and B vitamins. Although these nutrients are generally more difficult to obtain without meat or dairy, most kibbles contain vitamin and mineral pre-mixes that should compensate for natural shortages in base ingredients. The plant-based kibbles may be more sensitive to high-heat processing or storage conditions, according to David Gardner, Professor of Physiology at the University of Nottingham Veterinary School.

Sample representation

The sample selection of diets could explain some of the differences in nutritional analysis, with Brociek pointing out that the foods for the Brazilian study were all sourced from a market local to the researchers. The British team, similarly, sourced its samples from pet supermarkets in the Nottingham area and ended up with a selection of six plant-based dog foods.

Local sampling was intentional, as the research team wanted its study to reflect the quality of foods available to the average consumer. However, this also means that both studies represent a snapshot of what vegan manufacturers offer and might fail to capture variations in nutrient content that may occur between batches of a single brand of pet food, or even within a batch itself.

The researchers from the University of Nottingham excluded vegan cat food because they were unable to find enough vegan cat food on the market to assemble what they considered a meaningful sample.

Health implications

While the 2025 University of Nottingham study didn’t investigate nutrient absorption, other digestibility studies show favorable results. A review of the impact of vegan diets on health indicators, published in 2023 in the journal Veterinary Sciences, found no significant evidence that plant-based diets harm pet health, with a handful of studies suggesting potential benefits for dogs.

One survey of 1,400 pet owners in Canada and the US identified potential associations between plant-based diets and increased health and longevity in dogs. The results were published in the journal Research in Veterinary Science in 2022, although the research team at the Ontario Veterinary College warned of the effect of inherent bias.

A related survey of 1,300 cat owners published in BMC Veterinary Research in 2021 by the Ontario Veterinary College research team reported that vegan cats do not seem to enjoy the same benefits, though the cats showed no ill health – with the same caveat noted as to owner bias.

A handful of the six studies of vegan cat health included in the 2023 review did report signs of nutrient deficiencies and some associated inflammation and muscle damage, though the results were inconsistent between them. The inconclusive nature of these findings means the picture for cats seems to be more complex than that for dogs.

The review also found that many studies of plant-based dog and cat diets only followed the animals in question for a matter of weeks or months, which may not have allowed enough time for clinical signs of deficiency.

Guidance going forward

It is estimated, based on the results of the pet survey owners in Canada, that 1.6% of dogs and 0.7% of cats owned globally are fed vegan diets, primarily by owners who are themselves vegan.

Most research into these diets has been conducted since 2020, according to Dr. Andrew Knight, a veterinarian and adjunct Professor of Veterinary Medicine at Australia’s Murdoch University. The 2025 study from the University of Nottingham caps off a small but growing body of evidence suggesting meat-free diets are digestible for dogs and could come with some health and environmental benefits.

To align with the growing evidence, the British Veterinary Association (BVA) updated its recommendations in 2024, stating that a nutritionally complete vegan diet can be safe for dogs, while continuing to discourage meat-free diets for cats. FEDIAF, the body representing the European pet food industry, has adopted a similar position.