Gut microbiota dynamics in young children, adolescents and adults over a three-year period. microbiota_dynamics

Knowing about the changes that occur in the gut microbiota throughout life can help the diagnosis, treatment and prevention of metabolic and immune diseases. Here, we focus on the changes occurring during two under-studied periods: early childhood and adolescence. We analyze diversity, taxonomic composition, functional profile and temporal stability in 12 children, 13 adolescents and 35 adults over a three-year period, with 16S rRNA and shotgun metagenomic sequencing. Children entered the study as toddlers and had undergone a long period of breastfeeding, most of them being weaned during the study. Breastfeeding cessation contributed importantly to the convergence of the microbiota towards adult-like properties. The microbiota of the toddlers stabilized at around two years of age in terms of large-scale, rapid changes in diversity, composition, and functional profile, but further changes did occur both before and after adolescence. Therefore, adolescence remains a transitional period, in which some taxa and functions still differ from adult levels. These include, among others, Bifidobacterium, Streptococcus, Bacteroides fragilis and several Lachnospiraceae, as well as various functions related to energy metabolism. This suggests that changes occurring during adolescence may still affect the establishment of a healthy adult microbiota.