Hill's Science Diet Adult Urinary Hairball Control Vegetables & Tuna Stew Cat Food

6 ingredients in this list are ones we hold sourced evidence on , and none of them is contested in the veterinary literature.

• Beet Pulp · ingredient 13Well supportedThe fibrous material left after sugar is extracted from sugar beets, included as a moderately fermentable fiber source (commonly around 5 to 7.5% of the diet). Controlled feeding studies show it supports firm, good-quality stools and short-chain fatty acid production without impairing overall nutrient digestibility, so the 'cheap filler' characterization is not supported by the evidence.
• Fish oil (EPA + DHA omega-3) · ingredient 17Well supportedMarine-source omega-3 fatty acids (EPA and DHA) from fish oil. A randomized, double-blinded controlled trial (Roush 2010) found improved weight-bearing in dogs with osteoarthritis, and a 2022 meta-analysis identified clear clinical analgesic efficacy for omega-3-enriched diets and supplements.
• Powdered Cellulose · ingredient 7NeutralPurified plant cell-wall fiber (typically from wood pulp) used as an insoluble-fiber source, bulking agent, and anti-caking aid, often in weight-management diets. It is not absorbed and is poorly fermentable, so it firms stool and dilutes calories but yields little of the short-chain fatty acids that more fermentable fibers produce; EFSA's 2018 re-evaluation found no safety concern and no need for a numerical ADI.
• Wheat Gluten · ingredient 9NeutralThe concentrated protein fraction of wheat, used as a plant protein and binder; it is highly digestible in dogs (about 88% crude-protein digestibility in one feeding study). The 2007 pet-food deaths linked to wheat gluten were caused by criminal melamine adulteration of imported product to fake protein readings, a contamination event rather than a property of wheat gluten itself.
• Guar Gum · ingredient 20NeutralA soluble, viscous fiber from the guar bean used in small amounts to thicken and stabilize foods, mostly wet formulas. At higher dietary inclusion it can lower the digestibility of dry matter and protein in dogs, but it also produces metabolic effects such as reduced post-meal insulin and cholesterol; at the low levels used as a thickener these effects are minor.
• Taurine (supplemental) · ingredient 24NeutralA sulfur amino acid that dogs can normally synthesize from methionine and cysteine, so it is not classically essential for them. However, some breeds (e.g., golden retrievers) and some diets are linked to low taurine status and dilated cardiomyopathy: an observational study (Ontiveros 2020) associated non-traditional, largely grain-free diets with taurine deficiency and DCM-consistent echocardiographic changes in golden retrievers, though causation and mechanism remain under investigation.