title: Dietary Fiber and the Human Gut Microbiota: Application of Evidence Mapping Methodology.
abstract: Interest is rapidly growing around the role of the human gut microbiota in facilitating beneficial health effects associated with consumption of dietary fiber. An evidence map of current research activity in this area was created using a newly developed database of dietary fiber intervention studies in humans to identify studies with the following broad outcomes: (1) modulation of colonic microflora; and/or (2) colonic fermentation/short-chain fatty acid concentration. Study design characteristics, fiber exposures, and outcome categories were summarized. A sub-analysis described oligosaccharides and bacterial composition in greater detail. One hundred eighty-eight relevant studies were identified. The fiber categories represented by the most studies were oligosaccharides (20%), resistant starch (16%), and chemically synthesized fibers (15%). Short-chain fatty acid concentration (47%) and bacterial composition (88%) were the most frequently studied outcomes. Whole-diet interventions, measures of bacterial activity, and studies in metabolically at-risk subjects were identified as potential gaps in the evidence. This evidence map efficiently captured the variability in characteristics of expanding research on dietary fiber, gut microbiota, and physiological health benefits, and identified areas that may benefit from further research. We hope that this evidence map will provide a resource for researchers to direct new intervention studies and meta-analyses.
authors.affiliation: Nutritional Epidemiology, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA. caleigh.sawicki@tufts.edu.|Friedman School of Nutrition Science and Policy, Tufts University, Boston, MA 02111, USA. caleigh.sawicki@tufts.edu.
authors.forename: Caleigh M
authors.initials: CM
authors.lastname: Sawicki
authors.affiliation: Nutritional Epidemiology, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA. kara.livingston@tufts.edu.
authors.forename: Kara A
authors.initials: KA
authors.lastname: Livingston
authors.affiliation: Nutrition & Genomics Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA. martin.obin@tufts.edu.
authors.forename: Martin
authors.initials: M
authors.lastname: Obin
authors.affiliation: Energy Metabolism Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA. susan.roberts@tufts.edu.
authors.forename: Susan B
authors.initials: SB
authors.lastname: Roberts
authors.affiliation: Nutrition/Infection Unit, Department of Public Health and Community Medicine, Tufts University School of Medicine, Boston, MA 02111, USA. Mei_Chun.Chung@tufts.edu.
authors.forename: Mei
authors.initials: M
authors.lastname: Chung
authors.affiliation: Nutritional Epidemiology, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA. nicola.mckeown@tufts.edu.|Friedman School of Nutrition Science and Policy, Tufts University, Boston, MA 02111, USA. nicola.mckeown@tufts.edu.
authors.forename: Nicola M
authors.initials: NM
authors.lastname: McKeown
mesh_terms: D004043:Dietary Fiber / Q000008:administration & dosage*; D005232:Fatty Acids, Volatile / Q000378:metabolism; D005285:Fermentation; D000069196:Gastrointestinal Microbiome; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006801:Humans; D064887:Observational Studies as Topic; D009844:Oligosaccharides / Q000008:administration & dosage; D016032:Randomized Controlled Trials as Topic
chemical_list: D004043:Dietary Fiber; D005232:Fatty Acids, Volatile; D009844:Oligosaccharides
keywords: Bifidobacteria; Lactobacilli; cereal fiber; colonic fermentation; dietary fiber; evidence map; gut microbiota; oligosaccharides; resistant starch