Myths vs facts: Leaky Gut Test and allergy

The claim that a 'leaky gut' test can reliably diagnose or explain allergies is not scientifically supported. Such tests typically measure markers like zonulin or lactulose/mannitol permeability, which are research surrogates for intestinal barrier function but not clinically validated for allergy diagnosis. Allergies are diagnosed via specific IgE antibodies, skin prick tests, and medical history. IgG-based food tests, often linked to leaky gut, merely indicate immune exposure, not intolerance or allergy. The evidence for a causal link between increased intestinal permeability and allergy development is mostly mechanistic and animal-based; large human studies are lacking. Commercial providers greatly overstate clinical relevance. Consumers should not rely on these tests and should consult an allergist if allergy is suspected. The MyBody-X context contains no validating studies for leaky gut tests; existing entries on IgG tests and the gut-brain axis rate them as marketing. Therefore, the evidence level is 'marketing/unclear'.