IgG Unverträglichkeitstest: what are common causes?

IgG food intolerance tests are commonly marketed to identify food sensitivities, but the scientific evidence is weak. Elevated IgG levels against foods are usually a normal immune response to frequent dietary exposure, not a sign of intolerance. Studies show that IgG tests do not reliably diagnose food intolerances or allergies. Professional bodies such as the European Academy of Allergy and Clinical Immunology (EAACI) advise against their use. Common causes of positive IgG results include: regular consumption of certain foods, cross-reactivity between similar proteins, increased intestinal permeability (leaky gut), or non-specific immune activation. Individual genetic variations (e.g., in HLA genes) may influence IgG responses but lack clinical relevance. Test results are often not reproducible and can lead to unnecessary dietary restrictions. For proper assessment of food intolerances, established methods like elimination diets, breath tests, or lactose intolerance tests are recommended. In summary, IgG tests are not evidence-based for diagnosing food intolerances.