title: Whole Soy Flour Incorporated into a Muffin and Consumed at 2 Doses of Soy Protein Does Not Lower LDL Cholesterol in a Randomized, Double-Blind Controlled Trial of Hypercholesterolemic Adults.
abstract: BACKGROUND
  Soy protein may reduce coronary heart disease (CHD) risk by lowering LDL cholesterol, but few studies have assessed whether whole soy flour displays a similar effect.
  
  
  OBJECTIVE
  The aim of this study was to assess the dose effect of whole soy flour incorporated into muffins on plasma LDL cholesterol in hypercholesterolemic adults.
  
  
  METHODS
  Adults aged 30-70 y (n = 243) with elevated LDL cholesterol (≥3.0 and ≤5.0 mmol/L) were stratified by LDL cholesterol and randomly assigned to consume 2 soy muffins containing 25 g soy protein [high-dose soy (HDS)], 1 soy and 1 wheat muffin containing 12.5 g soy protein and 12.5 g whey protein [low-dose soy (LDS)], or 2 wheat muffins containing 25 g whey protein (control) daily for 6 wk while consuming a self-selected diet. Fasting blood samples were collected at weeks 0, 3, and 6 for analysis of plasma lipids [total, LDL, and HDL cholesterol and triglycerides (TGs)], glucose, insulin, C-reactive protein (CRP), and isoflavones. Blood pressures also were measured. Dietary intake was assessed at weeks 0 and 4 with the use of 3 d food records. Treatment effects were assessed with the use of intention-to-treat analysis with multiple imputation and LDL cholesterol as the primary outcome.
  
  
  RESULTS
  In total, 213 (87.6%) participants completed the trial. Participants were primarily Caucasian (83%) and mostly female (63%), with a mean ± SD body mass index (in kg/m2) of 28.0 ± 4.6 and systolic and diastolic blood pressures of 122 ± 16 and 77 ± 11 mm Hg, respectively. Despite a dose-dependent increase in plasma isoflavones (P < 0.001), neither HDS nor LDS had a significant effect on LDL cholesterol compared with control (mean ± SEM changes: control, -0.04 ± 0.05 mmol/L; HDS, 0.01 ± 0.05 mmol/L; and LDS, -0.04 ± 0.06 mmol/L). There were no significant treatment effects on total or HDL cholesterol, TGs, CRP, homeostatic model assessment of insulin resistance, blood pressure, or the Framingham 10-y CHD risk score.
  
  
  CONCLUSIONS
  Consuming 12.5 or 25 g protein from defatted soy flour incorporated into muffins does not reduce LDL cholesterol or other CHD risk factors in hypercholesterolemic adults. This trial was registered at clinicaltrials.gov as NCT01547585.
authors.affiliation: Guelph Food Research Centre, Agriculture and Agri-Food Canada, Guelph, Canada; Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Canada;
authors.forename: Emily Mt
authors.identifier: http://orcid.org/0000-0002-3777-7548
authors.initials: EM
authors.lastname: Padhi
authors.affiliation: Canadian Centre for Agri-Food Research in Health and Medicine, Agriculture and Agri-Food Canada, Winnipeg, Canada; and.
authors.forename: Heather J
authors.identifier: http://orcid.org/0000-0001-8069-2665
authors.initials: HJ
authors.lastname: Blewett
authors.affiliation: Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Canada;
authors.forename: Alison M
authors.initials: AM
authors.lastname: Duncan
authors.affiliation: Canadian Centre for Agri-Food Research in Health and Medicine, Agriculture and Agri-Food Canada, Winnipeg, Canada; and.
authors.forename: Randolph P
authors.initials: RP
authors.lastname: Guzman
authors.affiliation: Guelph Food Research Centre, Agriculture and Agri-Food Canada, Guelph, Canada;
authors.forename: Aileen
authors.initials: A
authors.lastname: Hawke
authors.forename: Koushik
authors.initials: K
authors.lastname: Seetharaman
authors.affiliation: Guelph Food Research Centre, Agriculture and Agri-Food Canada, Guelph, Canada;
authors.forename: Rong
authors.identifier: http://orcid.org/0000-0001-6537-1820
authors.initials: R
authors.lastname: Tsao
authors.affiliation: Glycemic Index Laboratories Inc., Toronto, Canada.
authors.forename: Thomas Ms
authors.identifier: http://orcid.org/0000-0001-9030-8575
authors.initials: TM
authors.lastname: Wolever
authors.affiliation: Guelph Food Research Centre, Agriculture and Agri-Food Canada, Guelph, Canada; dan.ramdath@agr.gc.ca.
authors.forename: D Dan
authors.identifier: http://orcid.org/0000-0002-7368-3127
authors.initials: DD
authors.lastname: Ramdath
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D001794:Blood Pressure; D001939:Bread; D002097:C-Reactive Protein / Q000032:analysis; D008078:Cholesterol, LDL / Q000097:blood*; D003327:Coronary Disease / Q000453:epidemiology / Q000517:prevention & control; D004032:Diet; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006937:Hypercholesterolemia / Q000097:blood* / Q000178:diet therapy*; D007328:Insulin / Q000097:blood; D007529:Isoflavones / Q000097:blood; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D045730:Soy Foods; D030262:Soybean Proteins / Q000008:administration & dosage*
chemical_list: D001786:Blood Glucose; D008078:Cholesterol, LDL; D007328:Insulin; D007529:Isoflavones; D008055:Lipids; D030262:Soybean Proteins; D002097:C-Reactive Protein
keywords: LDL cholesterol; cardiovascular disease; dose-response; isoflavones; randomized clinical trial; soy flour