Milk scenarios and gut microbiota in the first 1000 days of life

Human milk is the gold standard for infant nutrition, and breastfeeding should be started within the first hour of life. Cow's milk, other mammalian milk, or plant-based beverages should not be offered before 1 year of age. However, some infants require, at least in part, infant formulas. Even with subsequent enhancements throughout history, with the addition of oligosaccharides, probiotics, prebiotics, synbiotics, and postbiotics, infant formulas still have room for improvement in reducing the health gap between breastfed and formula-fed infants. In this regard, the complexity of infant formulas is expected to continue to increase as the knowledge of how to modulate the development of the gut microbiota is better understood. The objective of this study was to perform a non-systematic review of the effect of different milk scenarios on the gut microbiota.