title: High-Molecular-Weight β-Glucan Decreases Serum Cholesterol Differentially Based on the CYP7A1 rs3808607 Polymorphism in Mildly Hypercholesterolemic Adults.
abstract: β-Glucan, a soluble fiber with viscous property, has a documented cholesterol-lowering effect. The molecular weight (MW) of β-glucan, which contributes to viscosity, and an individual's genotype might influence the cholesterol-lowering efficacy of β-glucan.
  
  
  
  This study was designed to determine whether the cholesterol-lowering efficacy of barley β-glucan varied as a function of MW and the daily dose consumed. Our second aim was to determine whether any gene-diet interactions are associated with the cholesterol-lowering efficacy of β-glucan.
  
  
  
  In a randomized controlled crossover trial, 30 mildly hypercholesterolemic adults [12 men and 18 women, aged 27-78 y; body mass index (in kg/m(2)): 20-40; total cholesterol (TC): 5.0-8.0 mmol/L; LDL cholesterol: 2.7-5.0 mmol/L] were randomly assigned to receive a breakfast that contained either barley β-glucan at 3 g high MW (HMW)/d, 5 g low MW (LMW)/d, or 3 g LMW/d or a control diet, each for 5 wk. The washout period between the phases was 4 wk. Fasting blood samples were collected at the start and end of each phase for blood lipid analysis and genotyping.
  
  
  
  Consumption of 3 g HMW β-glucan/d lowered TC by -0.12 mmol/L (95% CI: -0.24, -0.006 mmol/L) compared with the control diet (P= 0.0046), but the LMW β-glucan, at either 3 g/d or 5 g/d, did not change serum cholesterol concentrations. This effect of HMW β-glucan was associated with gene-diet interaction, whereby individuals with the single nucleotide polymorphism (SNP) rs3808607-G allele (GG or GT) of the cytochrome P450 family 7 subfamily A member 1 gene (CYP7A1) had greater responses to 3 g HMW β-glucan/d in lowering TC than TT carriers (P= 0.0006).
  
  
  
  The HMW β-glucan rather than LMW β-glucan reduced circulating TC effectively in mildly hypercholesterolemic adults. The cholesterol-lowering effect of β-glucan may also be determined by the genetic characteristics of an individual. These data show that individuals carrying theCYP7A1SNP rs3808607-G allele are more responsive to the cholesterol-lowering effect of β-glucan with HMW than TT carriers. This trial was registered atclinicaltrials.govasNCT01408719.
authors.affiliation: Morden Research and Development Centre, Agriculture and Agri-Food Canada, Winnipeg, Canada; Departments of Human Nutritional Sciences and Richardson Center for Functional Foods and Nutraceuticals, Winnipeg, Canada.
authors.forename: Yanan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Morden Research and Development Centre, Agriculture and Agri-Food Canada, Winnipeg, Canada; Diabetes and Nutritional Sciences, King's College London, London, United Kingdom;
authors.forename: Scott V
authors.initials: SV
authors.lastname: Harding
authors.affiliation: Departments of Human Nutritional Sciences and.
authors.forename: Peter
authors.initials: P
authors.lastname: Eck
authors.affiliation: Morden Research and Development Centre, Agriculture and Agri-Food Canada, Winnipeg, Canada; Departments of Human Nutritional Sciences and Richardson Center for Functional Foods and Nutraceuticals, Winnipeg, Canada.
authors.forename: Sijo J
authors.initials: SJ
authors.lastname: Thandapilly
authors.affiliation: Guelph Food Research Center, Agriculture and Agri-Food Canada, Guelph, Canada; and.
authors.forename: Tamer H
authors.initials: TH
authors.lastname: Gamel
authors.affiliation: Guelph Food Research Center, Agriculture and Agri-Food Canada, Guelph, Canada; and.
authors.forename: El-Sayed M
authors.initials: el-SM
authors.lastname: Abdel-Aal
authors.affiliation: Animal Science, University of Manitoba, Winnipeg, Canada;
authors.forename: Gary H
authors.initials: GH
authors.lastname: Crow
authors.affiliation: Guelph Food Research Center, Agriculture and Agri-Food Canada, Guelph, Canada; and.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Tosh
authors.affiliation: Departments of Human Nutritional Sciences and Richardson Center for Functional Foods and Nutraceuticals, Winnipeg, Canada.
authors.forename: Peter Jh
authors.initials: PJ
authors.lastname: Jones
authors.affiliation: Morden Research and Development Centre, Agriculture and Agri-Food Canada, Winnipeg, Canada; Departments of Human Nutritional Sciences and Richardson Center for Functional Foods and Nutraceuticals, Winnipeg, Canada nancy.ames@agr.gc.ca.
authors.forename: Nancy P
authors.initials: NP
authors.lastname: Ames
mesh_terms: D000328:Adult; D000368:Aged; D000483:Alleles; D015992:Body Mass Index; D002790:Cholesterol 7-alpha-Hydroxylase / Q000235:genetics* / Q000378:metabolism; D008076:Cholesterol, HDL / Q000097:blood*; D008078:Cholesterol, LDL / Q000097:blood*; D018592:Cross-Over Studies; D005260:Female; D060005:Genotyping Techniques; D001467:Hordeum / Q000737:chemistry; D006801:Humans; D006937:Hypercholesterolemia / Q000097:blood / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D020641:Polymorphism, Single Nucleotide; D014280:Triglycerides / Q000097:blood*; D047071:beta-Glucans / Q000008:administration & dosage* / Q000737:chemistry
chemical_list: D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D014280:Triglycerides; D047071:beta-Glucans; C553219:CYP7A1 protein, human; D002790:Cholesterol 7-alpha-Hydroxylase
keywords: CYP7A1; cholesterol; molecular weight; polymorphism; β-glucan