Role of gut microbiota in the control of energy and carbohydrate metabolismVenema, KoenCurrent Opinion in Clinical Nutrition & Metabolic Care: July 2010 - Volume 13 - Issue 4 - p 432–438 doi: 10.1097/MCO.0b013e32833a8b60 Carbohydrates: David D'Alessio and Luc Tappy Abstract Author Information Purpose of review To describe the recent developments and insights gained in the role played by the colonic microbiota in energy and carbohydrate metabolism related to obesity in humans. Recent findings Previous findings that the ratio of Firmicutes and Bacteriodetes is important in energy harvesting and obesity have not been confirmed in recent studies. In fact, sometimes, the opposite results were obtained. Nevertheless, it is clear that the microbiota plays a role in energy extraction from nondigested carbohydrates in the form of production of short-chain fatty acids. Also, the microbiota plays a role in host metabolism by influencing and modulating host gene expression in various tissues. Summary Despite numerous recent studies trying to link the composition of the microbiota to obesity, the picture is far from clear, and it remains to be seen whether changes in microbiota composition are the cause or the consequence of obesity. Molecular studies reveal the enzyme machineries used by individual members of the microbiota to break down and ferment polysaccharides. Also, the mechanisms of host–microbe mutualism are becoming unraveled. Using stable-isotope-labeled substrates, the exact microorganisms involved in fermentation of the substrates and the exact metabolites that are produced from the substrate can be deciphered. TNO Quality of Life, Department of Biosciences, Zeist, The Netherlands Correspondence to Koen Venema, TNO Quality of Life, Department of Biosciences, P.O. Box 360, 3700 AJ Zeist, The Netherlands Tel: +31 30 6944703; fax: +31 30 6944075; e-mail: firstname.lastname@example.org © 2010 Lippincott Williams & Wilkins, Inc.