Evidence check: Leaky Gut Test in the context of allergy

The concept of 'leaky gut' (increased intestinal permeability) is scientifically controversial. No validated, standardized tests exist to reliably measure gut permeability in a way that is clinically useful for allergy diagnosis. Commercial tests marketed as 'leaky gut tests' (e.g., measuring zonulin, LPS, or stool markers) lack robust evidence linking them to allergic diseases. Major allergy and immunology societies (e.g., EAACI, DGAKI) advise against their use, as they do not improve diagnostic accuracy or treatment outcomes. Even if permeability is altered, the causal role in allergy development remains unproven. Established allergy diagnostics (specific IgE, skin prick tests, oral food challenges) remain the gold standard. Caveat: Do not use leaky gut tests for allergy assessment; they may lead to unnecessary dietary restrictions and false reassurance.