Diagnosis of food intolerance

Abstract

Food intolerance is defined as a reproducible adverse reaction to a specific food or food ingredient which is not psychologically based. Clearly any food in excess can cause a reproducible adverse reaction (e.g. loose stools caused by high fructose content of pears), but such events are not generally covered by the term food intolerance. The term usually also excludes toxic reactions (e.g. due to lectins in red kidney beans), poisoning (e.g. due to solanidine present in some potatoes) or irritant reactions (e.g. due to curry or hot drinks). In theory it is helpful to differentiate between reactions which are immunologically mediated (food allergy or hypersensitivity) and those which are not (e.g. due to a pharmacological mechanism), or where the mechanism is unknown (see Table 1). In practice, although an immunological mechanism may be suspected, on the basis of the speed and nature of the reaction, or on the basis of an association with a positive skin prick or RAST test, proof is usually lacking.