What role does IgG play in gut health?

IgG (immunoglobulin G) is primarily a blood antibody but is also present in the gut mucosa. Its role in gut health is nuanced: it contributes to immune defense against pathogens and may be elevated in inflammatory bowel disease or food-related immune reactions. However, commercial IgG food sensitivity tests are controversial – they often reflect normal dietary exposure rather than true intolerance or allergy. The evidence for using IgG levels to guide gut-health interventions is weak (mixed/unclear). For chronic GI issues, a medical workup (including IgA, endoscopy, or breath tests) is more appropriate. IgG alone is not a reliable marker for gut health; the mucosal immune system relies more on secretory IgA, the microbiome, and intestinal barrier integrity.