Question 1: (Amani)
It is very important for Physicians, researchers, and patients to understand the terminology used to define allergic diseases. Failure to do so can lead to inappropriate advice, prevention and ineffective treatment.
The term allergy is commonly refers to reactions or conditions related to an IgE antibody-mediated immunological mechanism following antigenic exposure. Antigen is a material that is capable of initiating an immune reaction when introduced into the human body (J.Genuis , 2010). Regarding food allergy, adverse food reactions (AFRs) can be classified into toxic and hypersensitivity reactions (HRs). When an immunological response has been occurred, hypersensitivity food reaction must be referred to as food allergy, while if the role of IgE is demonstrated, the suitable definition is IgE mediated food allergy. About 20 percent of individuals report an AFR, while food allergy shows lower prevalence: (0.5-3.8 percent in children and 0.1-1 percent in adults). (G.Gasbarrini, 2008).
Non-toxic food reactions are classified into immunological (food allergy) and non-immunological (food intolerance); food allergy is subdivided into:
IgE mediated: characterized by the presence of IgE specific antibodies and the exact relation between ingestion of food and the symptoms.
and non IgE mediated: Demonstrated by antibodies of different isotype from IgE :IgG, IgM, IgA which consists cell-mediated immunity (Fig….).
Hypersensitivity or sensitivity are referred to reproducible symptoms or signs initiated by exposure to certain stimulus at a dose tolerated by normal persons (S.G.O. Johansson2004). The primary differences between sensitivity and the allergy are that; an allergy involved the immune system reaction, but sensitivity characterized by non-immune system involved. whoever both could be somewhat serious as intolerance, variety of sign and symptoms can be show by sensitivities, allergy and intolerance. ( Reference)
Intolerance is nonimmune adverse reaction induced mostly due to metabolic deficits, like inability to digest lactose present in cow’s milk.
The cause of Intolerance could be enzymatic defect or the effect of vaso-active pharmacological substances exists in the food and could be either:
Enzymatic food intolerance: -Adverse food reaction induced by enzymatic defects of gastrointestinal tract.
The most common example is lactose intolerance which occur as a result of deficiency in beta-galactosidase which is facilitate the hydrolysis of lactose into two monosaccharide’s to be absorbed in the gut.
Pharmacological food intolerance: - is induced by vasoactive amines and other substances presents in food. For instance, histamine, phenylethylamine, dopamine, serotonin, this may produce pharmacological effects and different subsequent symptoms in intolerant patients, with dose–effect relationship.
Undefined intolerance: which resulted from non-identified mechanisms. For example , food additive reactions: sulphites,...