Tomato Pomace in dog and cat food

Is it OK for dogs and cats?

Dogs

No known concern at the amounts studied. In a feeding study, dogs digested diets with tomato pomace about as well as diets with the same amount of fibre from beet pulp, wheat bran or peanut hulls.

Cats

No known concern at the small amounts studied. Fibre is not considered an essential nutrient for cats. In one study, cats ate a diet with 2% tomato pomace mixed with Miscanthus grass fibre, an amount chosen to match commercial use. The authors reported no detrimental effects on health, stool quality or digestibility over 21 days.

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

What tomato pomace is

The EU Catalogue of feed materials lists 'tomato pulp [tomato pomace]'. It is the product left after pressing tomatoes (Solanum lycopersicum) to make tomato juice, mainly peel and seeds. Its crude fibre content must be declared. Fruit pomaces in general are by-products of juice or purée making, which are dried and often ground to a fine powder. One analysis found tomato pomace was about 57% total dietary fibre on a dry-matter basis: about 4% soluble and 53% insoluble.

Why it is in pet food

Dietary fibre affects how easily stools pass and how firm they are, which is why pet foods include fibre sources. Fruit pomaces hold water well, which may help in making wet pet food. In one cat study, 2% tomato pomace was added to a fibre blend to raise its soluble fibre. That amount was chosen to match commercial practice.

What it does in the food

Tomato pomace is mostly insoluble fibre, at about 13 parts insoluble to 1 part soluble. In lab tests with dog faecal bacteria, it fermented more than cellulose. Fruit fibres with a high insoluble share like this made less gas and fewer short-chain fatty acids than more soluble ones such as apple pomace. In general, poorly fermented fibres lower a diet's calories and add stool bulk, while fermentable fibres feed gut bacteria. In dogs, diets with 12.5% total dietary fibre from tomato pomace or other sources had lower dry matter digestibility than the control diet. Digestible and metabolisable energy were generally similar across the diets. In cats, the blend with 2% tomato pomace gave higher faecal branched-chain fatty acids than the cellulose or beet pulp diets. Fat digestibility on the blend was slightly lower than on the cellulose diet (91.2% vs 94.5%). The authors suggested the cellulose diet's slightly higher fat content or the lignin in Miscanthus grass as possible reasons.

Safety and limits

The EU lists tomato pomace as a feed material. The entry sets no maximum level and requires crude fibre to be declared. Cats were fed a diet with 2% tomato pomace, blended with Miscanthus grass, for 21 days. From blood chemistry, blood counts and the lack of clinical signs, the authors judged there were no negative health effects. Tomatoes contain glycoalkaloids, mainly α-tomatine. A 2009 review of foods toxic to pets names green tomatoes among the most common poisonous foods for cats. It also lists tomato among other foods that may cause intoxication in pets, without giving amounts. One study measured one tomato variety at 11 stages of ripeness. Its α-tomatine fell from 361 to 13.8 mg per 100 g fresh weight as the fruit turned red, and dehydrotomatine was not detected in red fruit. None of the sources cited here measured glycoalkaloids in tomato pomace itself.

What depends on the amount and the recipe

Amount: the cat study used 2% of the diet, chosen to match commercial use, while the dog study compared diets that each had 12.5% total dietary fibre. Batch: the fibre content of plant by-products varies with growing conditions, harvest time and plant maturity. Ripeness: glycoalkaloid levels in tomatoes are highest in green fruit and fall as it ripens.

Not the same as

• Tomato powder or dried tomatoes — Tomato pomace is not the whole fruit. It is mainly the peel and seeds left after pressing tomatoes for juice.
• Dried plain beet pulp — A different fibre source with a higher soluble-fibre share. In a dog study, it gave the most wet faeces and the lowest faecal dry matter of the fibres tested, including tomato pomace.
• Apple pomace — Another fruit pomace with a lower insoluble-to-soluble fibre ratio (about 6:1 versus 13:1). It fermented more in lab tests.

Sources

1. Commission Regulation (EU) 2022/1104 amending Regulation (EU) No 68/2013 on the Catalogue of feed materials — EUR-Lex, Publications Office of the European Union, 2022. Entry 5.35.1 tomato pulp [tomato pomace]: product of pressing tomatoes during tomato juice production, mainly peel and seeds. Crude fibre is the compulsory declaration. No maximum level.
2. de Godoy MRC, Kerr KR, Fahey GC Jr. Alternative dietary fiber sources in companion animal nutrition. Nutrients 5(8):3099-117 — Nutrients (MDPI), 2013. Fruit pomaces are dried, ground juice or purée by-products that bind water well (an advantage in wet foods). Fibre affects laxation and stool quality. Tomato pomace is 57% TDF with an insoluble:soluble ratio of 13:1 (apple 6:1). Fibres with a higher insoluble share made less gas and SCFA in a canine in vitro model. Non-fermentable fibres dilute caloric density and increase faecal bulk, and fermented fibres provide substrate for SCFA production by gut microbes.
3. Fahey GC Jr et al. Dietary fiber for dogs: II. Iso-total dietary fiber (TDF) additions of divergent fiber sources to dog diets and their effects on nutrient intake, digestibility, metabolizable energy and digesta mean retention time. J Anim Sci 68(12):4229-35 — Journal of Animal Science (American Society of Animal Science), 1990. Dogs were fed diets with 12.5% TDF from tomato pomace, beet pulp, peanut hulls, wheat bran or treated wheat straw. DM and OM digestibility were lower than the control but similar among fibre sources. DE and ME were generally similar. Beet pulp gave the most wet faeces and the lowest faecal DM.
4. Finet SE et al. Miscanthus grass as a novel functional fiber source in extruded feline diets. Frontiers in Veterinary Science 8:668288 — Frontiers in Veterinary Science, 2021. Fibre is not considered an essential nutrient for cats. 2% tomato pomace (with 7% Miscanthus) was chosen to reflect practical commercial inclusion and raise soluble fibre. The authors reported no detrimental effects on health, faecal quality or macronutrient digestibility over 21 days, based on serum chemistry, CBC and clinical signs. The blend gave higher BCFA and lower fat digestibility than cellulose. Tomato pomace is 56.9% TDF, 4.2% SDF and 52.7% IDF (DM basis) and ferments more than cellulose in vitro with canine faecal inoculum. TDF varies with growing conditions, harvest time and maturity.
5. Kovalkovičová N et al. Some food toxic for pets. Interdisciplinary Toxicology 2(3):169-76 — Interdisciplinary Toxicology, 2009. Names green tomatoes among the most common poisonous foods for cats. The conclusion lists tomato among other human foods that may cause intoxication in pets, without giving amounts.
6. Choi SH et al. Changes in free amino acid, phenolic, chlorophyll, carotenoid, and glycoalkaloid contents in tomatoes during 11 stages of growth. J Agric Food Chem 58(13):7547-56 — Journal of Agricultural and Food Chemistry (American Chemical Society), 2010. In one tomato variety, α-tomatine fell from 361 mg/100 g fresh weight (green stage 1) to 13.8 mg/100 g (red stage 8). Dehydrotomatine fell from 48.2 mg/100 g and was not detectable in red stages 8–11.

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.