Evidence check: IgG in the context of gut health

IgG testing for food sensitivities is frequently marketed in the context of gut health, but the scientific evidence is weak to mixed. Immunoglobulin G (IgG) is a normal antibody produced upon food exposure; its presence does not indicate intolerance or allergy. Major medical organizations, including the American Academy of Allergy, Asthma & Immunology (AAAAI) and EAACI, explicitly advise against using IgG tests to diagnose food allergies or intolerances. Studies show that IgG levels often reflect dietary frequency rather than pathology, and while some small trials report symptom improvement after IgG-guided elimination diets, these effects are likely due to placebo or the general benefits of dietary restriction. No robust mechanistic link between IgG and gut inflammation or dysbiosis has been established. For gut health assessment, validated biomarkers such as fecal calprotectin, lactoferrin, or comprehensive stool analysis (microbiome, parasites, inflammation) are more evidence-based. In summary, IgG food sensitivity tests lack clinical validity for gut health; they may lead to unnecessary dietary restrictions and anxiety. If you have persistent digestive issues, consult a gastroenterologist for proper diagnostic workup.