What term refers to the body's reaction to a specific food or ingredient?

The term that refers to the body's reaction to a specific food or ingredient is "allergy." Food allergies are complex immune system responses that occur when the body's immune system mistakenly identifies a typically harmless food protein as a threat. This leads to the production of antibodies called Immunoglobulin E (IgE), which can trigger a range of symptoms, from mild hives or digestive issues to severe anaphylaxis.

Food intolerances, on the other hand, do not involve the immune system; they typically refer to difficulties in digesting certain foods or ingredients due to enzyme deficiencies or sensitivities, and they can cause uncomfortable symptoms but are generally not life-threatening. Thus, while both terms relate to adverse reactions to foods, an allergy specifically relates to an immune response, making it the correct choice in this context.

The term "reaction" or "response" can be too vague, as they do not specifically indicate that an immune response is involved, which is a critical aspect when referring to food allergies.