Effect of Beta-Glucan on Cholesterol Lowering

Overview

The primary aim of this study is to determine whether the cholesterol-lowering efficacy of barley b- glucan varied as function of molecular weight (MW) and the total daily amount consumed. Our second aim is to investigate the mechanism responsible for the action, specifically, whether β-glucan lowers circulating cholesterol concentration via inhibiting cholesterol absorption and synthesis. Thirdly, we aim to determine if any gene-diet interactions are associated with cholesterol lowering by barley β-glucan. In addition, we aim to investigate the alteration of the gut microbiota after β-glucan consumption and the correlation between the altered gut microbiota and cardiovascular disease risk factors.

This study consists of four dietary phases which are separated by \>28 days wash-out period. During the treatment phase, participants will be provided with all meals for the 35 day period. Breakfast meals will be consumed under the supervision of the research staff and lunch, dinner and snacks will be provided to take home in take-out packaging. While subjects are on the wash-out period they will return to their normal diet. The meals are on a 7 day rotating schedule that reflect an average Canadian diet. Changes in blood lipids, body weight, and waist circumference will be measured during each treatment phase. Cholesterol absorption and synthesis will be examined by stable isotope method. Single nucleotide polymorphisms (SNPs), rs3808607 of gene CYP7A1and rs429358 and rs7412 will be determined byTaqMan® SNP Genotyping assay following the manufacturer's protocol. Fecal samples will be collected at the end of each intervention phase and will be subjected to Illumina sequencing of 16S rRNA genes.