title: Pilot dietary intervention with heat-stabilized rice bran modulates stool microbiota and metabolites in healthy adults.
abstract: Heat-stabilized rice bran (SRB) has been shown to regulate blood lipids and glucose, modulate gut mucosal immunity and inhibit colorectal cancer in animal and human studies. However, SRB's effects on gut microbial composition and metabolism and the resulting implications for health remain largely unknown. A pilot, randomized-controlled trial was developed to investigate the effects of eating 30 g/day SRB on the stool microbiome and metabolome. Seven healthy participants consumed a study meal and snack daily for 28 days. The microbiome and metabolome were characterized using 454 pyrosequencing and gas chromatography-mass spectrometry (GC-MS) at baseline, two and four weeks post-intervention. Increases in eight operational taxonomic units (OTUs), including three from Bifidobacterium and Ruminococcus genera, were observed after two and four weeks of SRB consumption (p<0.01). Branched chain fatty acids, secondary bile acids and eleven other putative microbial metabolites were significantly elevated in the SRB group after four weeks. The largest metabolite change was a rice bran component, indole-2-carboxylic acid, which showed a mean 12% increase with SRB consumption. These data support the feasibility of dietary SRB intervention in adults and support that SRB consumption can affect gut microbial metabolism. These findings warrant future investigations of larger cohorts evaluating SRB's effects on intestinal health.
authors.affiliation: Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO 80523, USA. amymarie@mac.com.
authors.forename: Amy M
authors.initials: AM
authors.lastname: Sheflin
authors.affiliation: Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA. Erica.Borresen@colostate.edu.
authors.forename: Erica C
authors.initials: EC
authors.lastname: Borresen
authors.affiliation: Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO 80523, USA. melissa.wdowik@colostate.edu.
authors.forename: Melissa J
authors.initials: MJ
authors.lastname: Wdowik
authors.affiliation: Department of Clinical Sciences, Animal Population Health Institute, Colorado State University, Fort Collins, CO 80523, USA. Sangeeta.Rao@colostate.edu.
authors.forename: Sangeeta
authors.initials: S
authors.lastname: Rao
authors.affiliation: Cancer Center of the Rockies, University of Colorado Health, Fort Collins, CO 80522, USA. Regina.Brown@uchealth.org.
authors.forename: Regina J
authors.initials: RJ
authors.lastname: Brown
authors.affiliation: Department of Horticulture and Landscape Architecture, Colorado State University, Fort Collins, CO 80523, USA. Adam.Heuberger@colostate.edu.
authors.forename: Adam L
authors.initials: AL
authors.lastname: Heuberger
authors.affiliation: Proteomics and Metabolomics Facility, Colorado State University, Fort Collins, CO 80523, USA. Corey.Broeckling@colostate.edu.
authors.forename: Corey D
authors.initials: CD
authors.lastname: Broeckling
authors.affiliation: Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO 80523, USA. Tiffany.Weir@colostate.edu.
authors.forename: Tiffany L
authors.initials: TL
authors.lastname: Weir
authors.affiliation: Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA. E.P.Ryan@colostate.edu.
authors.forename: Elizabeth P
authors.initials: EP
authors.lastname: Ryan
mesh_terms: D000328:Adult; D001644:Bifidobacterium; D001647:Bile Acids and Salts / Q000378:metabolism; D002264:Carboxylic Acids; D004035:Diet Therapy / Q000379:methods*; D005227:Fatty Acids / Q000378:metabolism; D005243:Feces / Q000382:microbiology*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007211:Indoles / Q000032:analysis; D008297:Male; D055442:Metabolome; D012275:Oryza; D010865:Pilot Projects; D045857:Ruminococcus
chemical_list: D001647:Bile Acids and Salts; D002264:Carboxylic Acids; D005227:Fatty Acids; D007211:Indoles; C058980:indole-2-carboxylic acid