Soybean Meal in dog and cat food

Is it OK for dogs and cats?

Dogs

The sources reviewed here do not describe a general problem with soybean meal for dogs eating a complete and balanced food. In one study, dogs fed up to 17% soybean meal for 24 weeks showed no diet-related changes in food intake or body weight and kept normal blood values, though a related digestibility test found more stool output; soy is a less common food allergen in dogs, and Merck notes soybeans were not among the suspect ingredients in diet-associated heart disease (DCM).

Cats

Cats need taurine in their diet, and plant proteins contain none, so a complete cat food must supply it from animal ingredients or added taurine. In one study of 18 cats, 3 months on a soy diet slightly raised thyroid hormone (T4) levels compared with a soy-free diet; the authors called the effect measurable but modest.

How settled this is: No known concern at the amounts used in complete foods

What soybean meal is

Soybean meal is a by-product of soybean oil production. The EU Catalogue of feed materials defines it as the product left after the oil is extracted from soybeans, followed by appropriate heat treatment, with a set maximum for urease activity. Dehulled soybean meal is made the same way from soybeans with the hulls removed. A 2021 systematic review describes it as made by grinding, heating and extracting the fat from the bean.

Why it is in pet food

It is a widely available protein source, and a 2021 systematic review notes that this helps lower the production cost of commercial dog foods. The same review says that when soy protein is combined with animal proteins, it complements the essential amino acid profile of the food.

What it does in the food

Soybean meal supplies energy, protein and essential fatty acids, mainly linoleic acid. It also contains antinutritional factors, such as protease inhibitors and phytates. It has carbohydrates that dogs do not digest, including the oligosaccharides raffinose and stachyose, which gut bacteria ferment. Heat processing such as extrusion inactivates the protease inhibitors, and Merck notes that the trypsin inhibitors in raw soybeans are destroyed by cooking. Under-processing can leave oligosaccharides that cause flatulence and poorer stools, while over-processing can damage protein quality. A 2021 systematic review found that in most studies, soybean meal lowered dry matter and energy digestibility compared with poultry offal meal; results for protein digestibility varied. The authors called properly processed soybean meal an excellent protein source, but said it must be combined with other proteins to supply all essential amino acids.

Safety and limits

Dogs: In a 24-week study of 36 adult dogs, soybean meal replaced up to 30% of the chicken protein in a complete diet, reaching 17% of the food. Food intake and body weight did not differ between diets, and blood values stayed within normal ranges. In a separate digestibility test with 12 dogs in the same paper, higher soybean meal levels increased fecal output and lowered fecal dry matter, while protein and fat digestibility rose. Merck lists soy as a less common food allergen in dogs. On diet-associated dilated cardiomyopathy (DCM), Merck notes that many suspect diets were high in pulses such as peas and lentils, and that soybeans were not among the suspect ingredients. Cats: Merck lists beef, fish and chicken as the most common food allergens in cats; soy is not on its list for cats. Cats need dietary taurine, and plant proteins contain none, so cat foods need animal protein or added taurine. In a crossover study, 18 healthy cats ate soy and soy-free diets for 3 months each. On the soy diet, total T4 rose by about 8% and free T4 by about 14%, and the number of cats with free T4 above the reference range rose from 1 to 4. No other measured values changed. The authors described the effect as measurable but modest.

What depends on the amount and the recipe

Processing matters. It needs enough heat to inactivate protease inhibitors and reduce oligosaccharides, but not so much that it damages the protein. The amount in the food and the other proteins it is paired with also matter. Dogs with a diagnosed soy allergy need to avoid it. Merck notes that flavoured chewable heartworm and flea medicines generally contain beef, pork or soy protein, whether or not it is listed on the label, which matters during an elimination diet trial. For cats, the complete food must supply taurine.

Not the same as

• Soybean oil — The fat extracted from soybeans; soybean meal is what is left after that oil is removed.
• Soy protein concentrate — Made from dehulled, defatted soybeans with a second extraction or enzyme treatment that lowers the non-protein (nitrogen-free extract) part.
• Soybean hulls — The seed coats removed during dehulling, declared for their fibre rather than protein.
• Soybean expeller (soybean cake) — Made by pressing the oil out instead of extracting it; the EU catalogue requires crude fat to be declared for it.
• Toasted or extruded whole soybeans — Whole heat-treated soybeans with the oil still in, not the defatted meal.

Sources

1. Commission Regulation (EU) 2022/1104 amending Regulation (EU) No 68/2013 on the Catalogue of feed materials (entries 2.18.1 to 2.18.7) — European Commission, EUR-Lex, 2022. Definitions of soya (bean) meal and dehulled soya (bean) meal (product of oil manufacture after extraction and appropriate heat treatment, with maximum urease activity), and of toasted soya beans, soya expeller (crude fat declared), soya hulls (crude fibre declared), extruded soya beans and soya protein concentrate (second extraction or enzymatic treatment to reduce nitrogen-free extract).
2. Vanelli K et al. Soybean meal and poultry offal meal effects on digestibility of adult dogs diets: Systematic review. PLoS One 2021;16:e0249321 — PLOS One, 2021. How soybean meal is made; protein, energy and linoleic acid content; antinutritional factors (protease inhibitors, phytates, non-starch polysaccharides) and fermented oligosaccharides (raffinose, stachyose); extrusion inactivates protease inhibitors; under- and over-processing effects; in most studies lower DM and energy digestibility, with protein digestibility the most variable result; availability lowers production costs; complements animal protein; properly processed it is an excellent protein source when combined with other proteins.
3. Menniti MF et al. Effect of graded inclusion of dietary soybean meal on nutrient digestibility, health, and metabolic indices of adult dogs. J Anim Sci 2014. doi:10.2527/jas.2013-7226 (abstract via Europe PMC) — Journal of Animal Science (record via Europe PMC), 2014. Study 1: 24-week feeding of up to 17% soybean meal (replacing up to 30% of dried chicken protein) to 36 adult dogs, with no diet-related differences in food intake or body weight and blood values within normal ranges. Study 2: 12-dog digestibility trial, with higher fecal output, lower fecal dry matter, and increased protein and fat digestibility as soybean meal rose.
4. Cutaneous Food Allergy in Animals (Adverse Food Reactions), Merck Veterinary Manual, professional version (full review Aug 2025) — Merck & Co. (Merck Veterinary Manual), 2025. Soy as a less common food allergen in dogs and absent from the cat allergen list; chewable or flavoured heartworm and flea medicines generally contain beef, pork or soy protein; many suspect diets in diet-associated DCM were high in pulses, and soybeans were not among the suspect ingredients.
5. Nutritional Requirements of Small Animals, Merck Veterinary Manual, professional version (full review Nov 2023, updated Sept 2024) — Merck & Co. (Merck Veterinary Manual), 2024. Trypsin inhibitors in raw soybeans are destroyed by cooking; cats require dietary taurine, and plant-based protein sources are devoid of it, so cats need animal protein or added synthetic taurine.
6. White HL et al. Effect of dietary soy on serum thyroid hormone concentrations in healthy adult cats. Am J Vet Res 2004;65:586. doi:10.2460/ajvr.2004.65.586 (abstract via Europe PMC) — American Journal of Veterinary Research (record via Europe PMC), 2004. Crossover study in 18 cats, 3 months per diet: soy raised total T4 by 8% and free T4 by 14%; cats above the fT4 reference range rose from 1/18 to 4/18; no other effects; authors called the effect measurable but modest.

Checked against these sources on 2026-10-15. Definitions are in our own words. This is a reading aid, not veterinary advice: a vet who knows your animal comes first.