Can LCT help with allergy?

The question of whether LCT (lactase persistence) can help with allergy is misleading. LCT encodes the lactase enzyme, which digests lactose. Variants determine lactose tolerance or intolerance, not allergic responses. Allergies involve immune reactions to proteins (e.g., milk protein), not sugars. There is no strong evidence linking LCT polymorphisms directly to allergy risk or symptoms. Some indirect effects via gut microbiota composition have been suggested, but effect sizes are small and not clinically actionable. For suspected food allergies, validated IgE testing by an allergist is essential. MyBody-X offers DNA tests for lactose intolerance, but these should not be confused with allergy tests. Evidence: mechanistic/unclear; no human trials confirm LCT-allergy link. Consumers should be aware that home DNA tests cannot diagnose allergies.