The role of the gut microbiota in nutrition and health

• Published in: Nature reviews. Gastroenterology & hepatology Vol. 9; no. 10; pp. 577 - 589
• Main Authors: Flint, Harry J., Scott, Karen P., Louis, Petra, Duncan, Sylvia H.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-10-2012; Nature Publishing Group
• Subjects: 631/443/319; 692/698/2741/2135; 692/699/1503; 692/699/1503/1702/393; Bacteria - metabolism; Biomedicine; Diabetes Mellitus - metabolism; Diet; Gastroenterology; Gastrointestinal Diseases - metabolism; Gastrointestinal Tract - metabolism; Gastrointestinal Tract - microbiology; Health aspects; Health Status; Hepatology; Host-bacteria relationships; Humans; Medicine; Medicine & Public Health; Metagenome - physiology; Microbial metabolism; Microbiota (Symbiotic organisms); Molecular microbiology; Nutritional Physiological Phenomena - physiology; Prebiotics; Probiotics; Properties; review-article; United Kingdom
• ISSN: 1759-5045; 1759-5053
• DOI: 10.1038/nrgastro.2012.156

The human gut harbours a vast array of micro-organisms and the benefits of these bacteria should not be forgotten. Here, Flint and colleagues discuss the role of the gut microbiota in nutrition and health, describing the development of these bacteria in the healthy gut, and their positive influences on microbial and human metabolism.
The microbial communities that colonize different regions of the human gut influence many aspects of health. In the healthy state, they contribute nutrients and energy to the host via the fermentation of nondigestible dietary components in the large intestine, and a balance is maintained with the host's metabolism and immune system. Negative consequences, however, can include acting as sources of inflammation and infection, involvement in gastrointestinal diseases, and possible contributions to diabetes mellitus and obesity. Major progress has been made in defining some of the dominant members of the microbial community in the healthy large intestine, and in identifying their roles in gut metabolism. Furthermore, it has become clear that diet can have a major influence on microbial community composition both in the short and long term, which should open up new possibilities for health manipulation via diet. Achieving better definition of those dominant commensal bacteria, community profiles and system characteristics that produce stable gut communities beneficial to health is important. The extent of interindividual variation in microbiota composition within the population has also become apparent, and probably influences individual responses to drug administration and dietary manipulation. This Review considers the complex interplay between the gut microbiota, diet and health.
Key Points
Molecular surveys have revealed remarkable diversity within the human gut microbiota, but certain dominant species are detected in faecal samples from most healthy adults
Dietary intake, especially of nondigestible carbohydrates, alters the species composition of the gut microbiota both in the short term and in the long term
Interindividual variation in colonic microbiota composition influences responses to dietary manipulation
The gut microbiota potentially influences the host's energy balance through multiple mechanisms, including supplying energy from nondigestible dietary components and influences on gut transit, energy intake and energy expenditure
Whether variation in gut microbiota composition is a major factor that influences obesity and metabolic disease in humans is not yet clear
The latest research has suggested new candidate organisms among the healthy gut microbiota that might be beneficial to gut health and new strategies for correcting dysbiosis associated with certain disease states