title: High Molecular Weight Barley β-Glucan Alters Gut Microbiota Toward Reduced Cardiovascular Disease Risk.
abstract: The physiological cholesterol-lowering benefits of β-glucan have been well documented, however, whether modulation of gut microbiota by β-glucan is associated with these physiological effects remains unknown. The objectives of this study were therefore to determine the impact of β-glucan on the composition of gut microbiota in mildly hypercholesterolemic individuals and to identify if the altered microbiota are associated with bioactivity of β-glucan in improving risk factors of cardiovascular disease (CVD). Using a randomized, controlled crossover study design, individuals received for 5-week either a treatment breakfast containing 3 g high molecular weight (HMW), 3 g low molecular weight (LMW), 5 g LMW barley β-glucan, or wheat and rice. The American Heart Association (AHA) diet served as the background diet for all treatment groups. Phases were separated by 4-week washout periods. Fecal samples were collected at the end of each intervention phase and subjected to Illumina sequencing of 16S rRNA genes. Results revealed that at the phylum level, supplementation of 3 g/d HMW β-glucan increased Bacteroidetes and decreased Firmicutes abundances compared to control (P < 0.001). At the genus level, consumption of 3 g/d HMW β-glucan increased Bacteroides (P < 0.003), tended to increase Prevotella (P < 0.1) but decreased Dorea (P < 0.1), whereas diets containing 5 g LMW β-glucan and 3 g LMW β-glucan failed to alter the gut microbiota composition. Bacteroides, Prevotella, and Dorea composition correlated (P < 0.05) with shifts of CVD risk factors, including body mass index, waist circumference, blood pressure, as well as triglyceride levels. Our data suggest that consumption of HMW β-glucan favorably alters the composition of gut microbiota and this altered microbiota profile associates with a reduction of CVD risk markers. Together, our study suggests that β-glucan induced shifts in gut microbiota in a MW-dependent manner and that might be one of the underlying mechanisms responsible for the physiological benefits of β-glucan.
authors.affiliation: Department of Human Nutritional Sciences-Richardson Centre for Functional Foods and Nutraceuticals, University of Manitoba, WinnipegMB, Canada; Cereal Research Center, Agriculture and Agri-Food Canada, WinnipegMB, Canada.
authors.forename: Yanan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Human Nutritional Sciences-Richardson Centre for Functional Foods and Nutraceuticals, University of Manitoba, WinnipegMB, Canada; Cereal Research Center, Agriculture and Agri-Food Canada, WinnipegMB, Canada.
authors.forename: Nancy P
authors.initials: NP
authors.lastname: Ames
authors.affiliation: Gut Microbiome Laboratory, Department of Animal Science, University of Manitoba, Winnipeg MB, Canada.
authors.forename: Hein M
authors.initials: HM
authors.lastname: Tun
authors.affiliation: Guelph Research and Development Center, Agriculture and Agri-Food Canada, Guelph ON, Canada.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Tosh
authors.affiliation: Department of Human Nutritional Sciences-Richardson Centre for Functional Foods and Nutraceuticals, University of Manitoba, Winnipeg MB, Canada.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Jones
authors.affiliation: Gut Microbiome Laboratory, Department of Animal Science, University of Manitoba, WinnipegMB, Canada; Department of Medical Microbiology, University of Manitoba, WinnipegMB, Canada.
authors.forename: Ehsan
authors.initials: E
authors.lastname: Khafipour
keywords: 16S rRNA gene sequencing; cardiovascular disease; gut microbiota; molecular weight; β-glucan