The binding of IgG antibodies with a bacterial or viral antigen, results in antigen coating and the formation of an immune complex. This consequently triggers further immune responses, including the release of pro-inflammatory cytokines, with the developing inflammation being accompanied by mechanical damage to the surrounding tissues.
The activity of IgG antibodies is identical as far as food antigens are concerned. As the food components in patients with increased intestinal permeability (leaky gut syndrome) enter the bloodstream from the intestinal lumen on a continuous basis, the immune mechanisms undergo constant activation. This can eventually overload the immune system’s ability to clear such complexes efficiently, which results in chronic inflammation.
Elevated levels of IgG antibodies to food antigens have been observed in diseases associated with increased intestinal barrier dysfunction; in particular, irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). The controversy surrounding food IgG testing, relates to the significance of food IgG antibodies in the pathogenesis and diagnosis of food intolerance and a number of chronic health conditions, including IBS, IBD and migraine. It should be noted however, that there are a number of clinical studies, that have in fact been supportive of a role for food IgG testing in certain health conditions.
The clinical manifestations of chronic IgG-mediated reactions are determined by the target tissue or organ to which the immune complexes composed of IgG antibodies and the specific food antigens are transported within the bloodstream. High levels of the complexes accompany such dissimilar disease entities as migraine, irritable bowel syndrome and Crohn’s disease. The protective nature of IgG antibodies becomes a property that severely burdens and disturbs the body’s homoeostasis. This type of hypersensitivity is the so-called delayed allergy or food intolerance. The signs and symptoms develop within 8–72 h after ingestion of the offending food.
Often, patients do not associate a given symptom with the food they ate, especially because of the lack of the characteristic “allergic” symptoms. This is the fundamental argument that highlights the controversial nature of this type III food allergy.
FoodPrint and Food Detective use specific food extracts to identify the corresponding level of circulating IgG antibodies to these potential antigens and can therefore detect foods to which the immune system is reacting. This can help to guide individuals towards making informed dietary changes with the support of a qualified nutritional therapist, in order to potentially alleviate unpleasant symptoms that they may be experiencing as a result of an IgG-mediated food intolerance.