Myths vs facts: IgG and longevity

The claim that IgG (immunoglobulin G) tests provide reliable indicators of food intolerances or direct insights into longevity is not supported by robust science. IgG antibodies are a normal part of adaptive immunity and merely reflect past antigen exposure, not necessarily an adverse reaction. Clinical guidelines from bodies like the European Academy of Allergy and Clinical Immunology (EAACI) explicitly advise against using IgG tests for food intolerance diagnosis due to high false-positive rates and lack of reproducibility. Regarding longevity, while chronic low-grade inflammation and immune aging (immunosenescence) are linked to lifespan, specific IgG levels are not validated as predictive biomarkers. Some research explores IgG subclass patterns in centenarians, but findings are preliminary and not actionable for individuals. Consumer DNA or blood tests that market IgG as a 'longevity marker' often overstate the evidence. The practical takeaway: IgG testing for longevity or food sensitivity is largely marketing, not evidence-based medicine. For meaningful healthspan insights, focus on established markers like hsCRP, lipid profiles, and modifiable lifestyle factors.