This difference between the clinically proven prevalence of food allergy and the public perception of the problem is in part due to reactions called "food intolerances" rather than food allergies. A true food allergy is an abnormal response to a food triggered by the body's immune system. Food intolerances, such as glucose intolerance, lactose intolerance, and reactions to food additives like sulfites, can cause symptoms that can resemble those of a food allergy. However, intolerances do not trigger the body's immune response as in a true food allergy.
It is extremely important for people who have true food allergies to identify them and prevent allergic reactions to food because these reactions can cause devastating illness and, in some cases, be fatal. In fact, the Centers for Disease Control and Prevention (CDC) estimates that food allergies cause 30,000 cases of anaphylaxis, 2,000 hospitalizations and 150 deaths annually.
Allergies are an inherited predisposition. Generally, people with a food allergy come from families in which allergies are common - not necessarily food allergies, but perhaps hay fever, asthma, or hives.