Food allergies and food sensitivites are abnormal responses to a food component triggered by the immune system in the form of immunoglobulins (IgE, IgG, IgA, IgM), representing either an immediate or delayed immune response. Elevated IgA antibodies to specific food proteins are believed to be a food sensitivity-related condition.

IgA antibodies are, like IgG antibodies, a part of the body’s immune system. They are mostly present in bodily secretions such as saliva and mucosa (secretory IgA), but are also secreted in the blood. Whilst a clear role for IgA towards food antigens remains unknown, high serum levels of IgA to specific food proteins are believed to be a possible indicator of antigen exposure and mucosal damage. Thus, elevated serum IgA towards specific food proteins may possibly suggest a loss of oral tolerance to the foods of concern. The only food-specific IgA antigen that was been established as an indicator of antigen-exposure is the gluten-related anti-gliadin IgA.