Brewer’s Yeast in Plant-Based and Vegan Pet Food: What It Adds and How to Specify It

Plant-based and vegan pet foods use brewer’s yeast for three jobs at once: a concentrated protein with a full amino acid profile, a savoury taste that dogs and cats accept, and natural B vitamins. Studies of extruded dog diets built on dried yeast report high digestibility and normal acceptance, which is why formulators keep it in recipes with no meat.

This guide is for brand owners, formulators and importers working on plant-based, vegetarian or flexitarian recipes. It covers where the demand comes from, what the research shows when yeast carries much of the protein, how to write the specification, and how to talk about the ingredient on pack.

Why do plant-based pet foods use brewer’s yeast?

Because a recipe without meat loses the ingredients that normally supply savoury flavour and a large share of the protein, and dried yeast covers part of both. Feedipedia lists brewers yeast at about 50% crude protein on a dry matter basis, within a range of 40 to 56%. That protein comes with all the essential amino acids dogs need, so it fills gaps left by pea, potato and other plant proteins.

The ingredient is also familiar to pet food buyers. The Pet Food Institute describes brewers dried yeast as an approved, common ingredient that tastes bitter to people but appeals to dogs and cats. Long-running vegan kibbles already rely on it: retailer listings for v-dog Kinder Kibble show brewers dried yeast as the tenth ingredient, in a recipe led by peas, pea protein, brown rice, oatmeal and potato protein.

How big is the demand for plant-based pet food?

Still a niche, with a much larger group of curious owners behind it. In a University of Guelph survey of 3,673 dog and cat owners (Dodd et al., 2019), 35% of owners whose pets ate conventional food said they were interested in switching to a plant-based diet. More than half of that group (55%) set conditions first: more evidence that the diet meets their pet’s needs, approval from their veterinarian, and products that are easy to buy.

Those three conditions are a useful brief for any brand in this space. Evidence and availability are things an ingredient supplier can help with; veterinary approval follows from them.

A second large survey, Knight et al. (2022) in PLOS ONE, asked guardians of 2,536 dogs about health outcomes. 336 of those dogs (13%) were fed vegan diets, and guardians reported health disorders for 36% of the vegan-fed dogs, against 49% for conventional meat diets and 43% for raw meat. These are owner reports, and the authors note that the groups differed in age. The study was funded by ProVeg International.

What happens when yeast supplies much of the protein?

Controlled feeding trials in dogs show that diets built on dried yeast are well digested and well accepted. Most of these trials used dried Saccharomyces cerevisiae in general rather than brewer’s yeast specifically, so they describe the yeast family that brewer’s yeast belongs to.

For a full review of the taste data, see our article on brewer’s yeast palatability in dry pet food.

Is brewer’s yeast vegan?

Yes, in the ordinary sense. Brewer’s yeast is a fungus grown on wort made from malted cereals, and the dried product contains no animal ingredients. Brands that put a vegan claim or a vegan certification mark on pack should still ask the supplier for a written declaration that no animal-derived processing aids are used between the brewery and the bag. Certification bodies ask for that paperwork, and it is quicker to collect at the sampling stage than after launch.

What should a plant-based recipe ask the supplier for?

The same core specification as any pet food recipe, with closer attention to protein and amino acids because yeast is carrying more of the nutrition.

Brewer’s yeast does not replace the vitamin and mineral premix. Plant-based dog and cat recipes still add the nutrients a complete and balanced formula requires, such as vitamin B12 and, for cats, taurine.

How should brands describe it on pack and online?

Use the exact feed name and let the ingredient’s role speak for itself. In California’s feed regulations, “brewers dried yeast” means non-fermentative yeast recovered from the brewing of beer and ale, with at least 35% crude protein. “Dried yeast” is a different definition, so the two names should not be swapped on a label.

The Dodd survey shows what plant-curious owners need before they buy: evidence, a vet’s approval and easy access. Copy that answers those needs is also safer than disease claims, which the FDA treats as drug claims. Practical examples:

• Name the protein sources plainly: “Protein from peas, potatoes and brewers dried yeast.”
• Point to published feeding studies instead of writing “clinically proven.”
• Give veterinarians the guaranteed analysis and the AAFCO or FEDIAF statement on the product page.
• When working with pet creators, have them show the ingredient list and the bowl being finished, and keep health outcomes out of the script.

Our guide to brewer’s yeast pet food claims sets out which statements are safe under FDA and AAFCO rules and how to brief creators.

Sources

• Dodd SAS, Cave NJ, Adolphe JL, Shoveller AK, Verbrugghe A (2019). Plant-based (vegan) diets for pets: A survey of pet owner attitudes and feeding practices. PLOS ONE 14(1): e0210806. doi.org/10.1371/journal.pone.0210806
• Knight A, Huang E, Rai N, Brown H (2022). Vegan versus meat-based dog food: Guardian-reported indicators of health. PLOS ONE 17(4): e0265662. doi.org/10.1371/journal.pone.0265662
• Reilly LM, He F, Rodriguez-Zas SL, Southey BR, Hoke JM, Davenport GM, de Godoy MRC (2021). Use of legumes and yeast as novel dietary protein sources in extruded canine diets. Frontiers in Veterinary Science 8: 667642. doi.org/10.3389/fvets.2021.667642
• Davenport GM, Block SS, Adolphe JL (2023). Effects of extruded pet foods containing dried yeast (Saccharomyces cerevisiae) on palatability, nutrient digestibility, and fecal quality in dogs and cats. Translational Animal Science 7(1): txad107. academic.oup.com
• ADM Animal Nutrition (2024). Plant and yeast protein for dogs: catering to flexitarian and vegetarian lifestyles. Technical bulletin.
• Feedipedia. Brewers yeast. INRAE, CIRAD, AFZ and FAO.
• Pet Food Institute. A to Z of pet food: brewers dried yeast.
• California Code of Regulations, Title 3, §2801 (yeast feed ingredient definitions).

Building a plant-based recipe?

We send 1 to 2 kg samples of TBESBY dried brewer’s yeast with a specification sheet and certificate of analysis, so your team can run its own trials. Request a sample or see the full product specification and our pet food supply page.