Food allergies and intolerances are adverse reactions of the organism but with totally different characteristics. They are two distinct ways of responding to interactions with foreign substances.

A food intolerance is a reaction that involves the body’s metabolic processes but not the immune system. It is triggered by the ingestion of one or more foods, or active ingredients, and depends on the amount of food consumed. Intolerances result from a lack of the enzymes needed to metabolize and assimilate certain foods.

The term allergy refers instead to an excessive reaction of the immune system to a foreign, normally harmless substance called an “allergen,” in genetically predisposed persons. Allergies are not dose-dependent: even a tiny quantity of the substance can trigger a reaction, whose severity is individual and unpredictable.

Learn more about the difference between food intolerances and allergies in this video from produced by the Communications Office of the Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe).