How are IgG and Darmgesundheit related?

The relationship between IgG and gut health is often discussed in the context of food intolerances. IgG antibodies (especially IgG4) are produced against food components, and elevated IgG levels are linked to delayed hypersensitivity reactions. However, the scientific evidence for a causal connection between IgG levels and actual gut disorders such as irritable bowel syndrome or increased intestinal permeability (leaky gut) is weak and contradictory. Many commercial IgG tests are marketed as diagnostic tools, but professional societies (e.g., DGE, EAACI) advise against their use because they are not sufficiently validated and may lead to unnecessary dietary restrictions. An altered IgG profile may be an epiphenomenon of a compromised gut barrier or increased antigen exposure, rather than a direct cause. Gut health is better assessed through stool markers (calprotectin, zonulin, microbiome analysis) and clinical symptoms. In summary: IgG and gut health are associated, but the evidence is mostly mechanistic and marketing-driven; IgG testing alone is not sufficient for diagnosis.