Food intolerance

Food intolerance 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 hypersensitivity is used to refer broadly to both food intolerances and food allergies. Food intolerance 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 hypersensitivity is used to refer broadly to both food intolerances and food allergies. Food allergies are immune reactions, typically an IgE reaction caused by the release of histamine but also encompassing non-IgE immune responses. This mechanism causes allergies to typically give immediate reaction (a few minutes to a few hours) to foods. 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. Food hypersensitivity is used to refer broadly to both food intolerances and food allergies. There are a variety of earlier terms which are no longer in use such as 'pseudo-allergy'. 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. Elimination diets are useful to assist in the diagnosis of food intolerance. There are specific diagnostic tests for certain food intolerances. Food intolerance is more chronic, less acute, less obvious in its presentation, and often more difficult to diagnose than a food allergy.Symptoms of food intolerance vary greatly, and can be mistaken for the symptoms of a food allergy. While true allergies are associated with fast-acting immunoglobulin IgE responses, it can be difficult to determine the offending food causing a food intolerance because the response generally takes place over a prolonged period of time. Thus, the causative agent and the response are separated in time, and may not be obviously related. Food intolerance symptoms usually begin about half an hour after eating or drinking the food in question, but sometimes symptoms may be delayed by up to 48 hours. Food intolerance can present with symptoms affecting the skin, respiratory tract, gastrointestinal tract (GIT) either individually or in combination. On the skin may include skin rashes, urticaria (hives), angioedema, dermatitis, and eczema. Respiratory tract symptoms can include nasal congestion, sinusitis, pharyngeal irritations, asthma and an unproductive cough. GIT symptoms include mouth ulcers, abdominal cramp, nausea, gas, intermittent diarrhea, constipation, irritable bowel syndrome (IBS),and may include anaphylaxis.