Pets
Fortified vegan pet food — and healthier dogs and cats in the data
16Studies in the review — no major harm found
A 2023 systematic review of 16 studies found no major harm from vegan diets in dogs and cats, and some signs of benefit. In large owner surveys, vegan-fed dogs and cats were rated as healthy or healthier than others. Bramble, a vegan collie, is widely reported to have lived to 25. The food still has to be complete — taurine, B12, and the rest. Dogs and cats do not need us to harm other animals for their food.
What the evidence says
The main points first. Every claim is tied to a source below.
The literature review found no major harm — and some benefit
Domínguez-Oliva and colleagues (Veterinary Sciences, 2023) searched the databases and found 16 studies. They found no convincing evidence of major harm from vegan diets in dogs or cats, and some evidence of benefits. That is the latest full review of the literature.
Thousands of dogs and cats on vegan food — equal or better health reports
Knight 2022 looked at 2,536 dogs and found vegan diets as good as or better than conventional meat diets. Knight 2023 looked at 1,369 cats and found vegan-fed cats tended to be healthier. Knight 2024 reported six disorders with 50–61% lower risk on vegan dog food. Owner reports can be biased. Sample sizes this large still matter.
The food has to be complete — then they digest it
Cats need taurine, vitamin A, arachidonic acid, and B12 in the bowl. Fortified vegan diets supply them. Knight 2026 found these foods are well digested and not significantly worse than meat diets. Homemade guesswork is not what these studies tested. Commercial complete vegan food is.
Bramble the vegan collie lived to a reported 25
That is about twice a typical collie lifespan. The story is widely told and owner-reported, not a Guinness record — Bluey the Australian cattle dog holds the verified record near 29. One long-lived vegan dog is an anecdote. The reviews are the stronger argument. She is the picture that sits on top of them.
Sources
Papers and datasets. Caveats stay on the card — small samples and single animals included on purpose.
Veterinary Sciences, 2023 · Review
Systematic review: vegan diets and dog/cat health
Domínguez-Oliva et al. searched Medline, Scopus, and Web of Science and pulled 16 studies. Conclusion: no convincing evidence of major adverse impacts of vegan diets on dog or cat health, and some evidence of benefits. This is a systematic literature review.
PLOS ONE, 2022 · Observational
2,536 dogs — vegan vs meat vs raw
Knight et al., PLOS ONE 2022: dogs on vegan diets had health indicators as good as or better than conventional meat. Raw looked slightly better on some owner reports; vegan diets scored better than conventional meat. N is large. It is still owner-reported.
PLOS ONE, 2023 · Observational
Cats on vegan food tended to be healthier
Knight et al., PLOS ONE 2023: 1,369 cats. Considering results overall, cats fed vegan diets tended to be healthier than cats fed meat-based diets. Only one difference reached statistical significance. Cats on complete, fortified vegan food were not worse off in this survey.
Heliyon / ScienceDirect, 2024 · Observational
Vegan dogs: 50–61% fewer of six disorders
Knight et al., 2024: for six specific disorders, vegan diets were associated with statistically significant risk reductions of 50–61% versus meat-fed dogs. The sample was large; the reductions were statistically significant.
Animals, 2026 · Review
Vegan pet food is well digested
Knight 2026 review: modern vegan and vegetarian diets for dogs and cats, and their protein sources, are broadly well digested. Not normally significantly less digestible than meat-based food. The combined evidence: nutritionally sound vegan diets, comparable or superior health.
Frontiers in Veterinary Science, 2024 · Review
Ten dog studies, three cat studies — as good or better
Knight, Frontiers in Veterinary Science 2024: ten studies in dogs and three in cats found vegan diets produce health outcomes as good as or better than non-vegan. Palatability comparable. Claims that vegan pet diets are nutritionally unsound do not match these papers.
Bramble, reported 25 years · Review
Bramble — vegan collie, reported age 25
Bramble, a collie fed a plant-based diet, is widely reported to have lived to 25 — about twice a typical collie span. Guinness’s verified oldest dog is Bluey, an Australian cattle dog, at about 29. Bramble is the famous vegan longevity case, not a certified world record. One dog is an anecdote; the reviews are the stronger evidence.