Infancy is the period of the life cycle with the highest growth rate, and thus meeting energy and nutrient needs is critical to ensure optimal development. Infants have comparatively high needs for most nutrients relative to body size. Moreover, compared with older children, very young infants have immature digestive, absorptive, and renal capacities. Therefore, human milk, with low renal solute load and compositional factors that facilitate nutrient absorption, is the ideal sole source of nutrition for healthy, term infants from birth through approximately 6 months of age. Besides promoting optimal growth, human milk contains many bioactive components, such as anti-infectious and anti-inflammatory agents, growth factors, and prebiotics [1].