Human milk contains a plethora of nutrients and bioactive components to help nourish the developing neonate and is considered the "gold standard" for early life nutrition-as befits the only food "designed" by evolution to feed human infants. Over the past decade, there is considerable evidence that highlights the "intelligence" contained in milk components that contribute to infant health beyond basic nutrition-in areas such as programming the developing microbiome and immune system and protecting against infection. Such discoveries have led to new opportunities for infant milk formula (IMF) manufacturers to refine nutritional content in order to simulate the functionality of breast milk. These include the addition of specialized protein fractions as well as fatty acid and complex carbohydrate components-all of which have mechanistic supporting evidence in terms of improving the health and nutrition of the infant. Moreover, IMF is the single most important dietary intervention whereby the human microbiome can be influenced at a crucial early stage of development. In this respect, it is expected that the complexity of IMF will continue to increase as we get a greater understanding of how it can modulate microbiota development (including the development of probiotics, prebiotics, and synbiotics) and influence long-term health. This review provides a scientific evaluation of key features of importance to infant nutrition, including differences in milk composition and emerging "humanized" ingredients.
Keywords: bioactives; composition; human milk; infant milk formula; microbiota; protection.