Grain allergy

In horses, the term “grain allergy” is often used colloquially as a synonym for intolerances relating to sugar and grain. An allergy actually refers to an excessive, pathological defence reaction of the immune system to normally harmless environmental substances (allergens). A genuine allergy to grain in horses exists, if at all, only in relation to gluten, the sticky protein found in wheat, spelt or barley. Otherwise, no allergies have so far been described in horses. However, when someone speaks of a “grain allergy”, they usually mean conditions relating to energy, sugar or carbohydrate metabolism.

Very often, the underlying cause is being overweight (obesity) and/or conditions such as EMS (Equine Metabolic Syndrome), Cushing’s (PPID) or PSSM (Polysaccharide Storage Myopathy), which mean that as little sugar and starch, i.e. grain, as possible should be fed.