Food allergy is defined as an adverse immunologic response to a food protein.[1] Although approximately 19% of adults in the US have a perceived adverse reaction to food, only 10.8% have a convincing history of true food allergy, according to a cross-sectional survey study.[2] In a separate study of US households, approximately 11% of children were perceived by their parents to have a food allergy, but only 7.6% had a convincing history of true food allergy.[3]
People who believe they have a food allergy may suffer from a metabolic intolerance to a particular food; for example, lactose intolerance. Others may be sensitive to a particular pharmacologically active component of food such as caffeine or tyramine. Some people may mistake bacterial food poisoning as a reaction to a particular food.[1] Although all of these scenarios involve food, they do not result from an abnormal immune response to a particular food protein and therefore cannot be considered a true food allergy.[4] Rather, some of them, such as lactose intolerance and sucrase-isomaltase deficiency, are considered nonimmune food intolerances, and others, such as tyramine and sulfite reactions, are considered nonimmune food sensitivities.
It is important that people with suspected food allergy are investigated and followed up appropriately so that they do not unnecessarily avoid food and impair their quality of life.[2]
