Effect of Beta-Glucan on Cholesterol Lowering

Not Applicable

Completed

Interventions: Dietary Supplement: 5g LMW beta-glucan
Dietary Supplement: 3g HMW beta-glucan
Dietary Supplement: Control
Dietary Supplement: 3g LMW beta-glucan

Brief Summary: 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.

Detailed Description: 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.

Recruitment & Eligibility

Inclusion Criteria

Exclusion Criteria

Pregnant or lactating
Taking lipid lowering medication or nutritional supplements that affect blood lipids
Dietary restrictions which would affect consuming the study diet for 5-wk for four study phases.
Not deemed healthy by study physician

Arm && Interventions

Group	Intervention	Description
3g LMW beta glucan	5g LMW beta-glucan	3 grams of low molecular weight beta-glucan diet for 35 days
Control	3g HMW beta-glucan	control diet containing negligible amount of beta glucan
5g LMW beta glucan	Control	5 gram low molecular weight barley beta-glucan diet for 35 days
3g HMW beta glucan	3g LMW beta-glucan	3 gram high molecular weight barley beta-glucan diet for 35 days

Primary Outcome Measures

Name	Time	Method
Changs in Total Cholesterol	Beginning and end of each phase	Fasted total cholesterol concentration will be measured using the automated enzymatic methods.
Changes in LDL Cholesterol	Beginning and end of each phase	Serum LDL cholesterol will be estimated using the Friedewald equation.

Secondary Outcome Measures

Name	Time	Method
Cholesterol Absorption/Synthesis	End of each phase	The rate of cholesterol absorption and synthesis will be measured in each intervention phase using single stable isotope labelling technique.
Potential Gene-nutrient Interactions: CYP7A1 and APOE	Once for each participant	The Single Nucleotide Polymorphism (SNP) rs3808607 of CYP7A1 gene, rs429358 and rs7412 of APOE gene, and their associations with different blood lipid responses to beta-glucan interventions will be determined.
Changes in Body Weight and Waist Circumference(WC)	Every day for body weight; beginning and end of each phase for WC	Body weight will be monitored every day when subject visits the Richardson Centre. Waist circumference will be measured at the beginning and end of each study phase.