Clinical guideline of the Asociación Mexicana de Gastroenterología for the diagnosis and treatment of lactose ingestion-related disorders.

The aim of the present Clinical Guideline of the Asociación Mexicana de Gastroenterología was to establish clear, updated, evidence-based recommendations for the diagnosis and treatment of lactose ingestion-related disorders (LIRDs), to improve diagnostic accuracy and promote effective, patient-centered clinical management. The methodology employed consisted of a Delphi process coordinated by three experts, with the participation of 15 Mexican specialists (gastroenterologists, pediatricians, and nutritionists). Three working groups (epidemiology/definitions, diagnosis, and treatment) were formed that thoroughly reviewed the medical literature published between 2010 and 2025. A total of 26 statements were formulated. The main results included the precise definition of the different LIRD phenotypes (lactase nonpersistence, hypolactasia, clinical lactose intolerance, self-perceived lactose intolerance, and lactose sensitivity); diagnostic test standardization, highlighting the lactose breath test as a highly sensitive noninvasive tool, complemented by genetic studies and biochemical tests; and the recommendation of personalized treatments ranging from the selective reduction of dietary lactose to the use of exogenous enzymes (lactase) and fermented dairy products. Likewise, the importance of avoiding unnecessary dietary restrictions that could compromise calcium and vitamin D intake was emphasized. Altogether, the present consensus provides a comprehensive framework to optimize the clinical care of patients with LIRDs in Mexico.