Lactose nutrition in lactase nonpersisters

Area of Science:

• Human gut microbiome
• Lactose metabolism
• Innate immunity

Background:

• Lactose handling beyond infancy is often viewed as a disorder, not a physiological process.
• Maternal milk lactose provides energy for neonates and infants, with potential additional functions.
• Infant gut microbiome development is influenced by birth mode, impacting lactose processing.

Purpose of the Study:

• To explore the potential role of maternal milk lactose in infant innate immunity.
• To investigate the fate of lactose in the infant gut and its interaction with the microbiome.
• To understand the persistence of lactose's immune function and its relation to lactase persistence.

Main Methods:

• Review of existing literature on lactose metabolism, gut microbiome, and innate immunity.
• Analysis of population genomics data regarding lactase persistence prevalence.
• Examination of dose-dependency and dietary factors influencing gastrointestinal symptoms (GIS) in lactase non-persistent individuals.

Main Results:

• Lactose may enhance innate immunity via cathelicidin antimicrobial peptide (CAMP), potentially synergizing with butyrate.
• Lactase persistence, prevalent in Northern European ancestry, emerged around 3000-1000 BC.
• Gastrointestinal symptoms in lactase non-persistent individuals are dose-dependent, with intakes ≤25g/day often tolerated.

Conclusions:

• Lactose may have a physiological role in innate immunity beyond early infancy, particularly in lactase non-persistent individuals.
• Individual differences in lactose sensitivity and GIS warrant clinical and public health consideration.
• Dietary patterns and intake timing can mitigate GIS in lactase non-persistent populations.