Human milk oligosaccharide secretion dynamics during breastfeeding and its antimicrobial role: A systematic review

Table 2 Maternal factors affecting human milk oligosaccharides composition

Factor	Key influence	Examples and mechanisms
Maternal genetics	Primary determinant of HMO diversity and abundance	Secretor Status: Active FUT2 gene leads to higher 2′-FL levels; Lewis blood type: Influences specific HMO fucosylation patterns
Dietary intake	Availability of substrates and cofactors for HMO synthesis	Carbohydrates: Essential for lactose core formation; PUFAs: Support sialylated HMO production; Micronutrients: Iron, zinc, and B vitamins enhance enzymatic activity
Maternal health status	Alters HMO composition and concentration	Obesity: Reduces fucosylated HMOs (e.g., 2′-FL); Diabetes: Lowers fucosylation and sialylation; Infections/Inflammation: Downregulates glycosylation enzymes
Stress levels	Impacts hormonal and metabolic pathways	Cortisol: Reduces sialylated HMO levels; Chronic Stress: Alters glycosylation balance and overall HMO diversity
Parity (number of pregnancies)	Enhanced mammary adaptation and metabolic efficiency in multiparous mothers	Higher HMO concentrations in multiparous mothers; Primiparous mothers may produce less diverse HMO profiles
Lactation stage	Dynamic changes in HMO levels during breastfeeding	Colostrum: High fucosylated and sialylated HMOs for immune protection; Mature Milk: Decline in total HMOs; increase in 3-FL for gut microbiota diversity
Environmental Conditions	Geographic, pollutant, and cultural influences on HMO secretion	Rural areas: Prolonged breastfeeding supports 3-FL and LNT secretion (e.g., Kenyan mothers); Pollutants: Disrupt metabolic pathways and reduce HMO diversity
Breastfeeding practices	Duration and exclusivity influence HMO exposure	Extended Breastfeeding: Enhances long-term microbial and immune benefits; Early Weaning: Reduces HMO exposure in critical periods

2′-FL: 2′-Fucosyllactose; 3′-FL: 3′-Fucosyllactose; HMOs: Human milk oligosaccharides; LNT: Lacto-N-Tetraose; PUFAs: Polyunsaturated fatty acids.