Immune Hypersensitivity to Foods: Why food?

Written By Dr. Wayne Sodano,
Director of Clinical Support & Education For Evexia Diagnostics

ImmuneHypersensitivity

“Allergic diseases are estimated to affect 10% to 25% of the general population. The prevalence of IgE-mediated food allergies in the U.S. can be estimated at 3.5% to 4.0% of the population, based on surveys indicating that the prevalence of shrimp, peanut, tree nut and fish allergies as 1.9%, 0.76%, 0.62%, and 0.4% of the overall population.”1 “Many young children outgrow their food allergies within a few months to several years after the onset of hypersensitivity. As many as 80% to 87% of children identified with food allergies are able to tolerate food by 3 years of age.”2 “The mechanisms involved in the loss of sensitivity to specific foods are not precisely known, but the development of immunologic tolerance is definitely involved.”3 It is this author’s opinion that preconception, prenatal care and postnatal care health measures can reduce the incidence of food allergies in young children.

Immune hypersensitivity refers to misdirected immune reactions. The immune system doesn’t usually mistake food for an aggressive allergen for several reasons: cooking denatures protein; proteolytic enzymes cleaves proteins into tri-peptides, dipeptides and amino acids that are easily absorbed and generally non-antigenic; and proteins and peptides that escape degradation are prevented from entering circulation due to a healthy mucosal barrier and an adequate level of immunoglobulins (i.e. sIgA).

Immune sensitivity to most foods begins with a combination of the degradation of the intestinal mucosa and decreased digestion (i.e. indigestion). True food allergies can be divided into two categories based on their immunological response: immediate hypersensitivity (i.e. IgE) and delayed hypersensitivity (non-IgE) reactions. “IgE and IgG immunoglobulins are the two main antibodies produced against food allergens (as well as pathogens). These antibodies react differently to the presence of food allergens. IgG has four main functions; opsonization – coats antigen for macrophage recognition; agglutination – limits the mobility of pathogens; complement activation; and antibody-dependent cell-mediated cytotoxicity – IgG (and IgE) bind to cells that are recognized as having foreign antigens, which can then bind to NK cells.

1Taylor SL, Baumert JL. Food Allergies and Intolerances. In: Ross AC, Caballero B, Cousins RJ, Tucker KL, Ziegler TR. Modern Nutrition in Health and Disease. 11th Ed. Baltimore: Lippincott Williams & Wilkins; 2014. p. 1425.

2 Ibid. p. 1428.

3 Ibid.

4 Ibid. p. 170.