IBS is an incredibly common complaint that affects 9-23% of people and presents with debilitating symptoms such as pain, straining, bloating, diarrhoea and constipation and reduces the quality of life. Consulting with medical doctors will result in allergy testing in the form of IgE antibodies, tests for coeliacs disease or inflammatory bowel disease. Fortunately, or unfortunately, depending on how you want to perceive this, the tests come back negative, leaving patients frustrated and even more confused as to why they are suffering with such debilitating symptoms and what it is that they can do about it. It is not surprising then that newer and controversial diagnostic and treatment protocols such as the IgG testing have evolved to help desperate patients in need, but are they reliable?
IgE allergic reactions to food are related to mast cell breakdown and more severe, immediate gastrointestinal hypersensitivity and anaphylaxis symptoms occur, such as urticaria or rashes, hives, asthma, swelling of the throat, tongue and oesophagus, vomiting or diarrhoea. Food intolerance, such as lactose intolerance, indicates and inability for the digestive system to breakdown certain molecules, such as the sugar lactose, which is then fermented by gut bacteria causing bloating and distress ¹.
Food sensitivities in turn are suggested to be mediated by IgG reactions, which normally modulate the immune’s response to food antigens, however in excessive amounts can create delayed type food sensitivity reactions due to repeated exposure and insufficient inhibition of the immune system, like the loss of tolerance mechanisms involved in the production of autoantibodies targeting self-tissues. Increased gastrointestinal permeability or “leaky gut” markers, increased IBS symptoms and increased migraine responses have all been associated with raised food specific IgG markers ² ³.
Numerous studies have shown that IBS sufferers benefitted from IgG diets, in fact in one research IgG was more effective than a FODMAP diet, which is commonly recommended for IBS patients and another larger study, performed by a group of gastro-enterologists and published in the The American College of Gastroenterology also showed marked improvement in IBS symptoms such as abdominal pain and bloating ⁴ ⁵ ⁶.
Although there seems to be some association between IgG and IBS, conventional medical professional associations such as The European Academy of Allergology and Clinical Immunology (EACCI), American Academy of Allergy, Asthma & Immunology (AAAAI) and World Allergy Organisation (WAO) caution against using these diagnostic tests and recommend elimination diets. Their view is that presence of raised IgG suggests repeated exposure to a food that the immune system recognises as foreign, but this is not a sign of hypersensitivity, but rather a marker of immune tolerance and is a normal response to ingested food and that there is not enough research to promote the use of these tests ⁷.
In conclusion, if you have not responded to conventional treatment options, perhaps IgG testing and dietary elimination protocol may be something for you to try, although it is recommended to do this under guidance of a practitioner and use reputable laboratory testing. If you would like to find out more, book a discovery call with us.
¹ Sicherer SH, Sampson HA. Food allergy: Epidemiology, pathogenesis, diagnosis, and treatment. J Allergy Clin Immunol. 2014; 133(2):291-307.
² Vita AA, Zwickey H, Bradley R. Associations between food-specific IgG antibodies and intestinal permeability biomarkers. Front Nutr. 2022; 9:962093.
³ Zhao ZM, Yang MM, Zhao XS, Wan FJ, Ning BL, Zhang LM, Fu J. The Impact of Food Specific IgG Antibodies on Migraine and Its Comorbidities. Immun Inflamm Dis. 2024;12(11):e70056.
⁴ Ostrowska L, Wasiluk D, Lieners CFJ et al. Igg Food Antibody Guided Elimination-Rotation Diet Was More Effective than FODMAP Diet and Control Diet in the Treatment of Women with Mixed IBS-Results from an Open Label Study. J Clin Med. 2021; 10(19):4317.
⁵ Lembo A, Chey WD, Lacy, BE et al. S521IgG-based Elimination Diets for Patients with IBS: Results From a Prospective, Multi-Center, Double-Blind, Placebo-Controlled Trial. The American Journal of Gastroenterology. 2022; 117(10S):p e368-e369.
⁶ Xie Y, Zhou G, Xu Y et al. Effects of Diet Based on IgG Elimination Combined with Probiotics on Migraine Plus Irritable Bowel Syndrome. Pain Res Manag. 2019; 2019:7890461.
⁷ Gocki J, Bartuzi Z. Role of immunoglobulin G antibodies in diagnosis of food allergy. Postepy Dermatol Alergol. 2016; 33(4):253-6.
