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Food intolerance (or non-allergic food hypersensitivity) is a detrimental reaction, often delayed, to a food, beverage, food additive, or compound found in foods that produces symptoms in one or more body organs and systems, but generally refers to reactions other than food allergy. Food allergies are immune reactions, involving mast cells in which food triggers release of mast cell mediators, such as histamine when the food allergen binds to pre-formed IgE antibodies already bound to the mast cell. This mechanism causing allergies to typically give immediate reaction (a few minutes to a few hours) to foods, 〔Olivier CE (2013) Food Allergy. J Aller Ther S3: 004. doi:10.4172/2155- 6121.S3-004 (Link )〕 There are numerous causes for other types of food sensitivities, most of which, in contrast to food allergies, cause delayed hypersensitivity reactions to the food. Food intolerances can be classified according to their mechanism. Intolerance can result from the absence of specific chemicals or enzymes needed to digest a food substance, as in hereditary fructose intolerance. It may be a result of an abnormality in the body's ability to absorb nutrients, as occurs in fructose malabsorption. Food intolerance reactions can occur to naturally occurring chemicals in foods, as in salicylate sensitivity. Drugs sourced from plants, such as aspirin, can also cause these kinds of reactions. Finally, it may be the result of non-IgE-mediated immune responses. == Definitions == ''Non-allergic food hypersensitivity'' is the medical name for food intolerance, loosely referred to as ''food hypersensitivity'', or previously as ''pseudo-allergic reactions''. Non-allergic food hypersensitivity should not be confused with true food allergies. Food intolerance reactions can include pharmacologic, metabolic, and gastro-intestinal responses to foods or food compounds. Food intolerance does not include either psychological responses〔 or foodborne illness. A non-allergic food hypersensitivity is an abnormal physiological response. It can be difficult to determine the poorly tolerated substance as reactions can be delayed, dose-dependent, and a particular reaction-causing compound may be found in many foods.〔(【引用サイトリンク】title=Food allergy and intolerance | Better Health Channel )〕 *Metabolic food reactions are due to inborn or acquired errors of metabolism of nutrients, such as in diabetes mellitus, lactase deficiency, phenylketonuria and favism. *Pharmacological reactions are generally due to low-molecular-weight chemicals which occur either as natural compounds, such as salicylates and amines, or to food additives, such as preservatives, colouring, emulsifiers and taste enhancers. These chemicals are capable of causing drug-like (biochemical) side effects in susceptible individuals.〔 *Gastro-intestinal reactions can be due to malabsorption or other GI Tract abnormalities. *Immunological responses are mediated by non-IgE immunoglobulins, where the immune system recognises a particular food as a foreign body. *Toxins may either be present naturally in food, be released by bacteria, or be due to contamination of food products.〔 Toxic food reactions are caused by the direct action of a food or substance without immune involvement.〔 *Psychological reactions involve manifestation of clinical symptoms caused not by food but by emotions associated with food. These symptoms do not occur when the food is given in an unrecognisable form.〔 Elimination diets are useful to assist in the diagnosis of food intolerance. There are specific diagnostic tests for certain food intolerances.〔〔〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「food intolerance」の詳細全文を読む スポンサード リンク
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