Abstract
The human gut is a lush microbial ecosystem containing about 100 trillion microorganisms, whose collective genome, the microbiome, contains 100-fold more genes than the entire human genome. The symbiosis of our extended genome plays a role in host homeostasis and energy extraction from diet. In this article, we summarize some of the studies that have advanced the understanding of the microbiome and its effects on metabolism, obesity, and health. Metagenomic studies demonstrated that certain mixes of gut microbiota may protect or predispose the host to obesity. Furthermore, microbiota transplantation studies in germ-free murine models showed that the efficient energy extraction traits of obese-type gut flora are transmissible. The proposed methods by which the microbiome may contribute to obesity include increasing dietary energy harvest, promoting fat deposition, and triggering systemic inflammation. Future treatments for obesity may involve modulation of gut microbiota using probiotics or prebiotics.
Similar content being viewed by others
References and Recommended Reading
Backhed F, Ley RE, Sonnenberg JL, et al.: Host-bacterial mutualism in the human intestine. Science 2005, 307:1915–1920.
Ley RE, Peterson DA, Gordon JI: Ecological and evolutionary forces shaping microbial diversity in the human intestine. Cell 2006, 124:837–848.
Turnbaugh PJ, Ley RE, Hamady M, et al.: The Human Microbiome Project. Nature 2007, 449:804.
Ogden CL, Carroll MD, Curtin LR, et al.: Prevalence of overweight and obesity in the United States, 1999–2004. JAMA 2006, 295:1549–1555.
Hill JO, Wyatt HR, Reed GW, Peters JC: Obesity and the environment: where do we go from here? Science 2003, 299:853–855.
Ogden CL, Yanovski SZ, Carroll MD, Flegal KM: The epidemiology of obesity. Gastroenterology 2007, 132:2087–2102.
Hill JO, Peters JC: Environmental contributions to the obesity epidemic. Science 1998, 280:1371–1374.
Raoult D: Obesity pandemics and the modification of digestive bacterial flora. Eur J Clin Microbiol Infect Dis 2008, 27:631–634.
Frank DN, St Amand AL, Feldman RA, et al.: Molecularphylogenetic characterization of microbial community imbalances in human inflammatory bowel diseases. Proc Natl Acad Sci U S A 2007, 104:13780–13785.
Mackowiak PA: The normal microbial flora. N Engl J Med 1982, 307:83–93.
Kinross JM, Von Roon AC, Holmes E, et al.: The human gut microbiome: Implications for future health care. Curr Gastroenterol Rep 2008, 10:396–403.
Dethlefsen L, McFall-Ngai M, Relman DA: An ecological and evolutionary perspective on human-microbe mutualism and disease. Nature 2007, 449:811–818.
DiBaise JK, Zhang H, Crowell MD, et al.: Gut microbiota and its possible relationship with obesity. Mayo Clin Proc 2008, 83:460–469.
Hooper LV, Midtvedt T, Gordon JI: How host-microbial interactions shape the nutrient environment of the mammalian intestine. Ann Rev Nutr 2002, 22:283–307.
Tennyson CA, Friedman G: Microecology, obesity, and probiotics. Curr Opin Endocrinol Diabetes Obes 2008, 15:422–427.
Parodi A, Paolino S, Greco A, et al.: Small intestinal bacterial overgrowth in rosacea: clinical effectiveness of its eradication. Clin Gastroenterol Hepatol 2008, 6:759–764.
Lin HC: Small intestinal bacterial overgrowth: a framework for understanding irritable bowel syndrome. JAMA 2004, 292:852–858.
Kassinen A, Krogius-Kurikka L, Makivuokko H, et al.: The fecal microbiota of irritable bowel syndrome patients differs significantly from that of healthy subjects. Gastroenterology 2007, 133:24–33.
Cani PD, Amar J, Iglesias MA, et al.: Metabolic endotoxemia initiates obesity and insulin resistance. Diabetes 2007, 56:1761–1772.
Hayashi H, Sakamoto M, Benno Y: Phylogenetic analysis of the human gut microbiota using 16S rDNA clone libraries and strictly anaerobic culture-based methods. Microbiol Immunol 2002, 46:535–548.
Woese CR: Bacterial evolution. Microbiol Rev 1987, 51:221–271.
Gill SR, Pop M, Deboy RT, et al.: Metagenomic analysis of the human distal gut microbiome. Science 2006, 312:1355–1359.
Eckberg PB, Bik EM, Bernstein CN, et al.: Diversity of the human intestinal microbial flora. Science 2005, 308:1635–1638.
Xu J, Bjursell MK, Himrod J, et al.: A genomic view of the human-Bacteroides thetaiotaomicron symbiosis. Science 2003, 299:2074–2076.
Pryde SE, Duncan SH, Hold GL, et al.: The microbiology of butyrate formation in the human colon. FEMS Microbiol Lett 2002, 217:133–139.
Ley RE, Backhed F, Turnbaugh P, et al.: Obesity alters gut microbial ecology. Proc Natl Acad Sci U S A 2005, 102:11070–11075.
Mueller S, Saunier K, Hanisch C, et al.: Differences in fecal microbiota in different European study populations in relation to age, gender, and country: a cross-sectional study. Appl Environ Microbiol 2008, 72:1027–1033.
Ouwehand A, Isolauri E, Salminen S: The role of intestinal microflora for the development of the immune system in early childhood. Eur J Nutr 2002, 41:132–137.
Palmer C, Bik EM, DiGiulo DB, et al.: Development of the human infant intestinal microbiota. PLoS Biol 2007, 5:e177.
Penders J, Vink C, Driessen C, et al.: Quantification of Bifidobacterium spp, Escherichia coli and Clostridium difficile in faecal samples of breast-fed and formula-fed infants by real-time PCR. FEMS Microbiol Lett 2005, 243:141–147.
Mackie RI, Sghir A, Gaskins HR: Developmental microbial ecology of the neonatal gastrointestinal tract. Am J Clin Nutr 1999, 69:1035S–1045S.
Backhed F, Ding H, Wang T, et al.: The gut microbiota as an environmental factor that regulates fat storage. Proc Natl Acad Sci U S A 2004, 101:15718–15723.
Backhed F, Manchester JK, Semenkovich CF, Gordon JI: Mechanisms underlying the resistance to diet-induced obesity in germ-free mice. Proc Natl Acad Sci U S A 2007, 104:979–984.
Turnbaugh PJ, Ley RE, Mahowald MA, et al.: An obesityassociated gut microbiome with increased capacity for energy harvest. Nature 2006, 444:1027–1031.
Ley RE, Turnbaugh PJ, Klein S, Gordon JI: Microbial ecology: human gut microbes associated with obesity. Nature 2006, 444:1022–1023.
Kalliomaki M, Collado MC, Salminen S, Isolauri E: Early differences in fecal microbiota composition in children may predict overweight. Am J Clin Nutr 2008, 87:534–538.
Rychlik JL, May T: The effect of a methanogen, Methanobrevibacter smithii, on the growth rate, organic acid production, and specific ATP activity of three predominant ruminal cellulolytic bacteria. Curr Microbiol 2000, 40:176–180.
Samuel BS, Gordin JI: A humanized gnotobiotic mouse model of host-archaeal-bacterial mutualism. Proc Natl Acad Sci USA 2006, 103:10011–10016.
Wellen KE, Hotamisligil GS: Inflammation, stress, and diabetes. J Clin Invest 2005, 115:1111–1119.
Pappo I, Becovier H, Berry EM, Freund HR: Polymyxin B reduces cecal flora, TNF production and hepatic steatosis during total parenteral nutrition in the rat. J Surg Res 1991, 51:106–112.
Jia W, Li H, Zhao L, Nicholson JK: Gut microbiota: a potential new territory for drug targeting. Nat Rev Drug Discov 2008, 7:123–129.
Fuller R: Probiotics in man and animals. J Appl Bacteriol 1989, 66:365–378.
Gionchetti P, Rizzello F, Venturi A, et al.: Oral bacteriotherapy as maintenance treatment in patients with chronic pouchitis: a double-blind, placebo-controlled trial. Gastroenterology 2000, 119:305–309.
Lee HY, Park JH, Seok SH, et al.: Human originated bacteria, Lactobacillus rhamnosus PL60, produce conjugated linoleic acid and show anti-obesity effects in diet-induced obese mice. Biochem Biophys Acta 2006, 1761:736–744.
Park Y, Albright KJ, Liu W, et al.: Effect of conjugated linoleic acid on body composition in mice. Lipids 1997, 32:853–858.
Larsen TM, Toubro S, Gudmendsen O, Astrup A: Conjugated linoleic acid supplementation for 1 yr does not prevent weight or body fat regain. Am J Clin Nutr 2006, 83:606–612.
Martin FP, Wang Y, Sprenger N, et al.: Probiotic modulation of symbiotic gut microbial-host metabolic interactions in a humanized microbiome mouse model. Mol Syst Biol 2008, 4:157.
Cani PD, Joly E, Horsmans Y, Delzenne NM: Oligofructose promotes satiety in healthy humans: a pilot study. Eur J Clin Nutr 2006, 60:567–572.
Cani PD, Neyrinck AM, Fava F, et al.: Selective increases of bifidobacteria in gut microflora improve high-fat-diet-induced diabetes in mice through a mechanism associated with endotoxaemia. Diabetologia 2007, 50:2374–2383.
Nicholson JK, Holmes E, Wilson ID: Gut microorganisms, mammalian metabolism and personalized health care. Nat Rev Microbiol 2005, 3:431–438.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Tsai, F., Coyle, W.J. The microbiome and obesity: Is obesity linked to our gut flora?. Curr Gastroenterol Rep 11, 307–313 (2009). https://doi.org/10.1007/s11894-009-0045-z
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11894-009-0045-z