Constipation and the Microbiome: Lumen Versus Mucosa! Eamonn M.M. Quigley  Gastroenterology  Volume 150, Issue 2, Pages 300-303 (February 2016) DOI: 10.1053/j.gastro.2015.12.023 Copyright © 2016 AGA Institute Terms and Conditions

Figure 1 Interactions between diet, the microbiota and colonic physiology in the pathogenesis of constipation. (1) Bile acids entering the colon are deconjugated and stimulate both motility and secretion; a deficiency of bile acids could promote constipation. (2) Dietary fiber and other poorly absorbed carbohydrates are metabolized to produce short chain fatty acids, which promote net fluid absorption and may also enhance motility. In individuals with a methanogenic microbiota, methane is produced, which has been shown to slow transit. (3) Changes in the mucosal or juxtamucosal microbiota could promote constipation by enhancing absorption. Red arrows indicate impacts of products of interactions between the colonic microbiota and luminal contents on colonic functions (luminal pH, mucosal absorption/secretion, colonic motility). Dashed arrows indicate effects that are proposed but not necessarily universally accepted. Gastroenterology 2016 150, 300-303DOI: (10.1053/j.gastro.2015.12.023) Copyright © 2016 AGA Institute Terms and Conditions