The Impact of Vegan Diets on Indicators of Health in Dogs and Cats: A Systematic Review

Abstract

There has been an increase in vegetarianism and veganism in human populations. This trend also appears to be occurring in companion animals, with guardians preferring to feed their animals in accordance with their own dietary values and choices. However, there has been controversy amongst vets and online commentators about the safety of feeding vegan diets to carnivorous species, such as cats and dogs. In spite of this controversy, to date there has been no systematic evaluation of the evidence on this topic. A systematic search of Medline, Scopus, and Web of Science was performed, identifying 16 studies on the impact of vegan diets on cat and dog health. Studies were appraised for quality using established critical appraisal tools or reporting guidelines. There was considerable heterogeneity in the outcomes measured, and study designs employed, with few studies evaluating key outcomes of interest. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was utilized for assessment of certainty in the evidence, with the evidence for most outcomes being assessed as low or very low. Whilst the quality and amount of evidence needs to be considered in formulating recommendations, there was no overwhelming evidence of adverse effects arising from use of these diets and there was some evidence of benefits. It is, however, recommended that future high-quality studies, with standardized outcome measures and large sample sizes, be conducted. At the current time, if guardians wish to feed their companion animals vegan diets, a cautious approach should be taken using commercially produced diets which have been formulated considering the nutritional needs of the target species.

The relative benefits for environmental sustainability of vegan diets for dogs, cats and people

“…However, a sizeable and rapidly-growing body of evidence has now shown that both dogs and cats can thrive on nutritionally-sound vegan diets. Such results are evident within both canine (nine studies: [16][17][18][19][20][21][22][23][24]) and feline (four studies: [23,[25][26][27]) studies of health outcomes. Furthermore, their behavioural needs and welfare are not compromised by such diets [28].…”

“…A considerable body of recent evidence indicates that provided such diets are formulated to be nutritionally-sound, as modern commercial vegan diets usually are [15], dogs and cats maintained on vegan diets can have longevity and health at least equivalent, and in some respects superior, to those maintained on conventional meat-based diets. Such results are evident within studies of health outcomes in both dogs (nine studies: [16][17][18][19][20][21][22][23][24]) and cats (four studies: [23,[25][26][27]). Dietary palatability also appears equivalent overall [28].…”

Have the environmental benefits of insect farming been overstated? A critical review

“…Regarding health and palatability, while there are numerous methodological limitations with the existing literature, the latest systematic review found that plant-based pet foods are comparable, or perhaps slightly more advantageous, for the health of pet dogs and cats (Domínguez-Oliva et al, 2023). However, a cautious approach is warranted, as further validation and controlled clinical trials are required (Davies, 2022).…”

Pet Wellness and Vitamin A: A Narrative Overview

“…Dietary sources serve as pathways through which pets obtain nutrients, and understanding the availability of vitamin A in various diets is crucial for ensuring optimal pet health [10,11]. The decisions about pet diets are not just about providing food; they are intentional choices that significantly impact the pets' wellness by shaping their nutritional needs [12,13]. Vitamin A, sourced from various foods, becomes a critical consideration, whether obtained from animal products or as a precursor from plant-based sources.…”