Table.

Differences between MOM and DHM as a Function of Mammary Gland Maturity and Stage of Lactation

Component	Function	Colostrum and Transitional Preterm MOM	Mature MOM	DHM
Bioactive Proteins, including: Immunoglobulins Protective cytokines and chemokines Milk fat globule membrane (17–26,32,50,90,91)	Anti-inflammatory Anti-infective Gut barrier protection Epigenetic Immunomodulation May have role in early immune programming	High in MOM colostrum Higher in preterm MOM colostrum Highest in very preterm MOM colostrum Decline slowest for least mature (earliest gestational age) mammary gland	Become constant after 1 month post-birth Selective elevation in components following exposure to pathogens in infant environment (enteromammary pathway)	Lower than mature MOM due to freezing, and pasteurization Little or no bioactivity in some components
Growth Factors, including: Epidermal growth factor Transforming growth factor Vascular endothelial growth factor Insulin-like growth factor-1 Erythropoietin (33,34,57,92)	Function synergistically to promote growth, maturation and protection of GI tract May be especially important for very preterm infants who had less swallowing of amniotic fluid Potential for absorption via open paracellular pathways in intestinal epithelium early post-birth Speculated role in specific organ growth and protection	High in MOM colostrum Higher in preterm MOM colostrum Highest in very preterm MOM colostrum Decline slowest for least mature (earliest infant gestational age) mammary gland	Reduced markedly after 1 month post-birth	Further reduced with pasteurization Bioactivity varies with growth factor; some are eradicated, and some are preserved
Macronutrients, including Protein Lactose Lipid (26,36,60–62,91)	Provide substrate for growth and development Mature MOM lipids are the most variable and the most prone to iatrogenic deficiencies in the NICU setting	Marked longitudinal changes due to tight junction closure in mammary epithelial cells High total protein due to bioactive proteins, growth factors, MOM-borne hormones and other non-nutritional protein High whey to casein ratio (little or no casein in colostrum) Low lactose and lipid in colostrum, that increase in transitional MOM	Lowest protein content in mammalian milk, but Proteome is highly specific to human, targeting immunologic and neurologic protection Lactose remains relatively constant, but is higher in foremilk than hindmilk Lipid is highly variable and affected by NICU practices	Multiple freeze-thaw cycles and container changes reduce lipid All HM-borne digestive enzymes are significantly reduced (amylases and proteases) are destroyed (lipases) with pasteurization, reducing bioavailability
Metabolic Hormones, including: Leptin Adiponectin (51–54,56,59,93)	Metabolic regulation May have role in early nutrition programming	Leptin and adiponectin highest in colostrum and decline thereafter	Higher in hindmilk than composite or foremilk Leptin stabilizes at 2 months post-birth Adiponectin declines over lactation	Significant reductions with pasteurization that are additive to longitudinal decline
Milk Microbiome MOM-borne commensal bacteria that are not skin contaminants Highly specific to individual mother (19,31,94)	Thought important to early gut colonization May be linked to individual MOM oligosaccharides for prebiotic substrate May have role in early immune and nutritional programming May have role in neuroprotection	Present in colostrum Present in preterm MOM as early as 24 weeks of gestation Highly variable among mothers	Increase in number and type between colostrum and mature milk	Destroyed with pasteurization
Oligosaccharides Complex sugars without nutritional value 3rd highest solute in MOM (higher than MOM protein) >200 identified in MOM Marked individual variability in number and type (19,69,95,96)	Prebiotic Anti-microbial Anti-adhesive Epithelial and immune cell modulation Potential role in neurodevelopment	Highest in colostrum and transitional MOM Highly individual depending upon secretor status of mother	Same pattern profile as in early lactation, but lower concentrations	Largely preserved with storage and pasteurization Different oligosaccharide pattern from infant’s MOM
Soluble CD14 Pattern recognition receptor (13,70,55)	Facilitates bacterial-enterocyte crosstalk in the immature gut	Higher in colostrum than mature HM	Lower than colostrum 20 X higher than maternal serum concentrations	88% reduction with pasteurization and freeze-thaw cycles

Note: Numbers in parentheses of component column denote citations.