The media has recently presented various articles on food allergy, some noting that food allergy is actually present in about  2% of the population. This figure raises a question of definition, which is not new, but remains a source of confusion.  To most of the public and many members of the medical profession, if a certain food causes physical problems to one person but not to most others, the person is presumed to be allergic to the food. This definition is also the most widely accepted definition in Europe.

However, in the United States, food allergy is usually defined as a reaction mediated by immunoglobulin e (IgE), an anaphylactic response quite rare and easily recognized, as the reaction is immediate and may be life-threatening.  Actually, it is well known that many parts of the immune system may produce an adverse reaction to a specific food, which most lay people and many physicians would define as "allergy."  To further complicate the situation, the definitions used in the venues mentioned are not uniform. The term "allergy," "hypersensitivity," and "intolerance" may often mean different things in different reports.  The question is definition, and is unfortunate that few articles make the effort to clarify the definition in use, as this might greatly alter the figures presented. For those interested, every effort should be made to clarify the definition being used.