Distinct Clinical Phenotypes in Lactase Nonpersistence: Symptomatic, Asymptomatic, and Gassy-Asymptomatic

Seventy percent of genetically LNP adults tolerate lactose without symptoms. Classifying LNP individuals into distinct subgroups and incorporating hydrogen production rate into breath-test interpretation may enhance diagnostic precision, prevent unnecessary dietary restrictions, and generate new hypotheses linking fermentation kinetics and symptoms. Microbiome associations remain correlative and warrant functional validation in larger, controlled studies.