Introduction to Current Knowledge on Micronutrients in Human Milk: Adequacy, Analysis, and Need for Research

The WHO (1) recommends breast milk as the sole source of nutrients for infants during the first 6 mo postpartum and as an important source for ages ≥2 y. This recommendation is supported by evidence that feeding breast milk, rather than formula or other liquids and foods, reduces the risk of infant morbidity and mortality, supports better child development (2), and influences the development and modulation of the infant's immune system. Moreover, although it has been known for several decades that, in addition to nutrients, human milk contains hundreds of important bioactive factors, we are beginning to understand the mechanisms by which human-milk oligosaccharides, proteins, peptides, and other factors interact with the intestinal microbiome to protect the infant against infections (3–5)