GUT MICROBIOTA, METABOLISM AND CALORIC BALANCE

The human metagenome is a composite of Homo sapiens genes and genes present in the genomes of the trillions of microorganism that colonize our bodies (microbiome). Our largest collection of microbes resides in the gut, where an estimated 10-100 trillion organisms reside. The gut microbiome encodes matabolic capacities that remain largely unexplored but include the degradation of otherwise indigestible components of our diet. Obesity results from alterations in body's regulation of energy intake, expenditure, and storage. Comparisons of the distal gut microbiota of genetically obese mice and their lean littertmates, as well as those of obese and lean human volunteers have revealed that obesity is associated with changes in the relative abundance of the two dominant bacterial divisions (phylum), the Bacteroidetes and the Firmicutes. Those results suggest that the gut microbiota affects nutrient acquisition and energy regulation. In this article, we review the published evidence supporting the potential role of the gut microbiota in the development of obesity and explore the role that modifying the gut microbiota may play in its future treatment.