title: Gut microbiome composition is linked to whole grain-induced immunological improvements.
abstract: The involvement of the gut microbiota in metabolic disorders, and the ability of whole grains to affect both host metabolism and gut microbial ecology, suggest that some benefits of whole grains are mediated through their effects on the gut microbiome. Nutritional studies that assess the effect of whole grains on both the gut microbiome and human physiology are needed. We conducted a randomized cross-over trial with four-week treatments in which 28 healthy humans consumed a daily dose of 60 g of whole-grain barley (WGB), brown rice (BR), or an equal mixture of the two (BR+WGB), and characterized their impact on fecal microbial ecology and blood markers of inflammation, glucose and lipid metabolism. All treatments increased microbial diversity, the Firmicutes/Bacteroidetes ratio, and the abundance of the genus Blautia in fecal samples. The inclusion of WGB enriched the genera Roseburia, Bifidobacterium and Dialister, and the species Eubacterium rectale, Roseburia faecis and Roseburia intestinalis. Whole grains, and especially the BR+WGB treatment, reduced plasma interleukin-6 (IL-6) and peak postprandial glucose. Shifts in the abundance of Eubacterium rectale were associated with changes in the glucose and insulin postprandial response. Interestingly, subjects with greater improvements in IL-6 levels harbored significantly higher proportions of Dialister and lower abundance of Coriobacteriaceae. In conclusion, this study revealed that a short-term intake of whole grains induced compositional alterations of the gut microbiota that coincided with improvements in host physiological measures related to metabolic dysfunctions in humans.
authors.affiliation: Department of Food Science and Technology, University of Nebraska, Lincoln, NE 68583, USA.
authors.forename: Inés
authors.initials: I
authors.lastname: Martínez
authors.forename: James M
authors.initials: JM
authors.lastname: Lattimer
authors.forename: Kelcie L
authors.initials: KL
authors.lastname: Hubach
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Case
authors.forename: Junyi
authors.initials: J
authors.lastname: Yang
authors.forename: Casey G
authors.initials: CG
authors.lastname: Weber
authors.forename: Julie A
authors.initials: JA
authors.lastname: Louk
authors.forename: Devin J
authors.initials: DJ
authors.lastname: Rose
authors.forename: Gayaneh
authors.initials: G
authors.lastname: Kyureghian
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Peterson
authors.forename: Mark D
authors.initials: MD
authors.lastname: Haub
authors.forename: Jens
authors.initials: J
authors.lastname: Walter
mesh_terms: D000328:Adult; D041963:Bacteroidetes / Q000254:growth & development; D001644:Bifidobacterium / Q000254:growth & development; D044822:Biodiversity; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000032:analysis; D018592:Cross-Over Studies; D004032:Diet; D002523:Edible Grain; D005051:Eubacterium / Q000254:growth & development; D005243:Feces / Q000382:microbiology; D005260:Female; D041981:Gastrointestinal Tract / Q000276:immunology / Q000378:metabolism / Q000382:microbiology*; D001467:Hordeum; D006801:Humans; D007249:Inflammation / Q000097:blood; D007328:Insulin / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D054892:Metagenome; D012275:Oryza; D055815:Young Adult
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D007328:Insulin; D015850:Interleukin-6