Le microbiote intestinal : un nouvel acteur de la nutrition ?

For 20 years, obesity is not only seen as a simple modification of the energy balance even if the changes in lifestyles are important. Behind the body mass index are hidden complex phenotypes, clinical trajectories and different pathophysiological mechanisms. The causal role of gut microbiota -billions of bacteria living in symbiosis in our intestinewas highlighted by stool transfer studies in rodents. These studies have also stressed the importance of diet-microbiota interactions, and products of these interactions (metabolites, infl ammatory factors) in the ability to infl uence metabolic and infl ammatory phenotypes of the host. In human obesity, the sequencing methods were used to identify changes in the diversity and in the balance of major bacterial groups. The concept of intestinal dysbiosis is proposed. It is associated with more severe clinical phenotypes. The modeling of the microbiota, as whole ecosystem and its interactions with food is a promising fi rst step towards a new therapeutic lead: individualized nutrition.