Gut microbiota: Changes throughout the lifespan from infancy to elderly

Our understanding of the composition and function of the human gut microbiota has improved dramatically in recent years. In this review, major milestones along this path will be reviewed. The methodological developments that underpinned this acceleration of scientific progress are discussed. We review the infant microbiota with special reference to colonization, succession and stabilization events. The healthy adult microbiota is then described, including reference to selected conditions that perturb the microbiota such as antibiotic treatment, bowel dysfunction and obesity. We put special emphasis on the special issues that characterize elderly subjects, including the challenges provided by inflamm-aging, with reference to how the microbiota might interact with these processes. Lastly, the elderly intestinal metagenomics project ELDERMET is described, which aims to establish the composition and function of the gut microbiota in several hundred Irish subjects. (C) 2009 Elsevier Ltd. All rights reserved.