Pet Food Allergen Directory

Barley is a gluten-containing cereal used as a carbohydrate source in mid-tier pet foods. It has a lower glycaemic index than rice and contributes fibre when pearled or hulled. Dogs with confirmed gluten sensitivity — rare outside specific breeds like the Irish Setter — should avoid.

Beef is the second-most-reported canine food allergen after chicken. Because it frequently appears as "meat meal" or "by-product" without species identification, dogs with known beef sensitivity can be exposed through generic meat ingredients on budget foods.

Chicken is the most commonly reported food allergen in both dogs and cats. Despite its ubiquity in mainstream pet foods, chicken allergy often develops in pets fed chicken-based diets for years, then appears seemingly overnight as the immune system escalates its response to a long-familiar protein.

Corn is one of the most misunderstood ingredients in pet food. Frequently labelled a "filler," it is actually ~9% protein and highly digestible when ground finely — pet-food industry digestibility data puts cooked corn at 85-90%. True corn allergy is uncommon, though specific dogs do react.

Dairy reactions in pets split into two distinct categories: true protein allergy (immune-mediated, reacts to whey or casein) and lactose intolerance (enzyme deficiency, reacts to milk sugar). The symptoms overlap but the fix differs — lactose-free dairy is safe for the intolerant pet, not the allergic one.

Egg allergies in pets target the egg white — specifically ovalbumin, ovomucoid, and conalbumin proteins. Egg yolk alone is rarely problematic. Dogs with a chicken allergy often react to whole egg through cross-reactivity with chicken serum albumin.

Fish allergy is less common than chicken or beef in dogs but is a leading allergen in cats. Cross-reactivity between fish species is unusually high — parvalbumin proteins shared across most fish mean a pet allergic to salmon typically also reacts to tuna, whitefish, and herring.

Lamb was historically marketed as a hypoallergenic "novel protein" — but its widespread use in sensitive-stomach formulas for the past 20+ years has eroded that status. Sensitised dogs are now common. For elimination diets, vets more often prescribe genuinely novel proteins like kangaroo, venison, rabbit, or duck.

Oats are primarily used in pet food for their soluble fibre (beta-glucan) rather than their protein. They contain a naturally-occurring gluten protein (avenin) that cross-reacts with wheat gluten in some sensitised dogs — so oats are not always a safe substitute for wheat-reactive pets.

Pea protein is a concentrated protein fraction extracted from yellow or green peas, widely used to boost crude protein on labels of grain-free formulas without increasing animal-ingredient cost. Separately from classic IgE allergy, pea-heavy diets were identified by the FDA as a recurring pattern in the ongoing DCM (dilated cardiomyopathy) investigation.

Pork was considered a near-novel protein until it was widely marketed as an alternative to chicken and beef. Dogs that react to pork often do so because their owners chose it specifically to avoid chicken or beef — a common frustration in the food-allergy community.

Rice is one of the most digestible carbohydrates in pet food and a standard component of veterinary bland diets. True rice allergy is rare — it is usually recommended as the carbohydrate to use during elimination diets precisely because reactions are uncommon.

Soy appears in pet food as soybean meal (protein source), soy flour, or soy hulls (fibre). It is more common in budget-tier kibble than in premium formulas. Soy oil rarely triggers the allergy because the offending protein fraction is largely absent — but whole soy and soybean meal do.

Wheat allergy in dogs is less common than headline "grain-free" marketing implies. True wheat sensitivity exists, particularly in specific breeds — Irish Setters carry a well-characterised gluten enteropathy mutation — but most dogs tolerate wheat without incident. Distinct from the DCM concern, which involves peas and lentils, not wheat.