The gut microbiota and obesity in humans

Abstract

In recent years, the human gut microbiome has been linked to a wide range of host metabolic effects, via modulation of energy harvesting, lipid and glucose metabolism, inflammatory responses, and brain-gut axis activity. Numerous observational studies have yielded important results regarding the structure and adaptive responses of the gut microbiota in obesity. However, animal studies still represent the principal demonstration of direct causality regarding the obesogenic effects of microbiota modulation. In this chapter, we aimed at analyzing and summarizing available studies on the relationships between gut microbiota and obesity in humans. Several observational and interventional studies have established the possibility of assessing and targeting bacterial populations by various means, including diet, surgery, pre-/probiotics, antibiotics, and fecal transplant. However, protocols and results widely differ, thus rendering cautious any interpretation of causality. Advances in methodology and technique availability are promising in widening the possibilities for original research and possible development of individualized therapeutic tools.