HUMAN milk is not constant in the quality of its content or in its function. Its subtle variations, if fully captured by exclusive breastfeeding for at least six months, showcase its multipurpose nature and potential for robust health endowments.

By continued and exclusive breastfeeding, the infant is gifted a comprehensive “vaccination without adverse reactions” against a spectrum of communicable diseases with enhanced combat against causative agents. There is some protection against a host of non-communicable diseases by the direct action of a number of its constituents and indirectly, by its possible impact on reducing obesity. It enhances cognition and growth in the term and preterm infant, such effects augmented by healthy nutrition and constructive environments later on. The early framework for health by exclusive and continued breastfeeding is best realised later on in life by a healthy lifestyle.

The subject of variations in human milk is a controversial one and is still under study. However, it is recognised that a mother’s nutritional intake and dietary status may influence her milk quality. Maternal “hidden hunger” of specific micronutrient deficiencies, though not all, and the lack of adequate holistic support to the lactational dyad may affect the quality of milk, and interfere with some of its potential short- and long-term benefits.

Some human milk micronutrients are more likely to be influenced by maternal dietary intake. Pregnancy may predispose to micronutrient deficiencies and may well be worsened by reduced maternal consumption of micronutrients such as vitamin A, vitamin B12, iodine, riboflavin, and others, during lactation. This could ominously affect micronutrient levels in a mother’s milk.  The roller coaster of reduced milk micronutrient levels impacts the nursing infant, who does not have sufficient stores of these nutrients. Lactational deficiencies of micronutrients could negatively impact development and longevity and arguably mar the generational effect.

The breastfeeding mother whose lactation is supported and boosted by early skin-to-skin contact “vaccinates” the newborn, cradles him or her for physical and emotional stability, and guides immunity. Colostral interferon has potent antiviral action while also containing enzymes, immunoglobulins, white blood cells, key nucleotides and others.

By supporting the mother and infant through continued lactation, the growing infant is wholly nourished by the advantages of mature human milk. Progressively increasing quantities of glutamine and glutamic acid throughout lactation focuses on gut development, the gut being a crucial driver of immune maturation. Possibly also acting as brain neurotransmitters, the milk amino acid profile provides a dynamic nutritive basis that sets the stage for rapid leaps in physical and cognitive expansion. Differences in the milk of the mother who delivers a premature infant which is variably supplied with proteins and specific amino acids, bioactive and growth factors compared to term milk, reflect the greater needs for growth in the preterm and the responsiveness of the specific mother-child network.

The ideals of lactation are best appreciated by the exclusive and uninterrupted supply of human milk carbohydrates, the milk energy reservoir, as energy sources for surges in development, facilitating essential mineral absorption, and for gut health. Proteins, fats, and carbohydrates in human milk are easily absorbed and contribute to an infant’s growth. The infant enjoys ample quantities of milk and, generally, sufficient macronutrient content in the feeds even if the mother is undernourished, as this fraction is comparatively unaffected by the mother’s nutritional status. However, human milk fatty acids can be influenced by a mother’s recent diet. The rapidly growing infant fully captures the complete array of variations in human milk, including specific ingredients in milk with a circadian rhythm through exclusive breastfeeding for at least six months.

Simultaneously, human milk has the potential to modulate the dynamics of growth as it delivers a spectrum of appetite-regulating hormones with a potential role in obesity prevention. In preventing obesity and its related co-morbidities, a timely vehicle against non-communicable diseases is gifted through human nutrition.  

During infections (unless specifically advised otherwise) continued and exclusive breastfeeding are advantageous and should not be halted or interrupted. Cells in human milk are versatile in purpose and during an infant’s infection, some may gain added capacity to engulf and combat the infecting agent, pepping up milk immunity. Also enriched by bioactive factors and a unique microbial milieu “immune crosstalk” in the breastfed infant bolsters the immature gut and respiratory mucosae, portals of entry for a spectrum of infective agents. The influential maternal microbial profile can also shield the child from immediate and long-term disorders.

The older child who continues to breastfeed derives calories primarily from fat and still receives a good supply of crucial nutrients from milk, even while he or she is introduced to complementary foods. Importantly, extended breastfeeding, through various means, is useful to the child and may confer an anti-cancer impact on the persistent breastfeeding mother.

Overall, the range of variations found in human milk stresses that the ideals of lactation are energised by exclusive and continued breastfeeding while underscoring the interdependence of maternal and child health. – August 23, 2022.

* Dr Prameela Kannan Kutty is professor of paediatrics at the University of Cyberjaya.

* This is the opinion of the writer or publication and does not necessarily represent the views of The Malaysian Insight. Article may be edited for brevity and clarity.