Defining and Directing Gut Microbiota Maturation in Early Life: A Nutrition Perspective

The development of the microbiome within the human digestive tract starts at birth and continues up to approximately 3 years of age when the microbial ecosystem resembles a more adulthood-like state. The pace of colonization and diversification of the gut microbiota in the early stages of life has been linked to short- and long-term health outcomes. Characterizing optimal maturation of the ecosystem may help identifying adverse events that impair the process and also factors that support and guide it, such as diet. To date, researchers have looked at the evolution over time of gut microbiota parameters such as diversity, taxa abundance, or specific functions. A more global approach has used "microbiota age" to capture maturation trajectory through machine learning models. In this review, the use and limitations of the latest methods to capture and understand microbiota maturation will be discussed. Then the role of nutrition in directing gut microbiota maturation in early life will be described together with the challenges that limit our comprehension of the effects of diet on the gut microbiota.