title: The effect on the blood lipid profile of soy foods combined with a prebiotic: a randomized controlled trial.
abstract: The value of soy protein as part of the cholesterol-lowering diet has been questioned by recent studies. The apparent lack of effect may relate to the absence of dietary factors that increase colonic fermentation and potentiate the cholesterol-lowering effect of soy. Therefore, unabsorbable carbohydrates (prebiotics) were added to the diet with the aim of increasing colonic fermentation and so potentially increasing the hypocholesterolemic effect of soy. Twenty-three hyperlipidemic adults (11 male, 12 female; 58 +/- 7 years old; low-density lipoprotein cholesterol [LDL-C], 4.18 +/- 0.58 mmol/L) completed three 4-week diet intervention phases-a low-fat dairy diet and 10 g/d prebiotic (oligofructose-enriched inulin, a fermentable carbohydrate), a soy food-containing diet (30 g/d soy protein, 61 mg/d isoflavones from soy foods) and 10 g/d placebo (maltodextrin), and a soy food-containing diet with 10 g/d prebiotic--in a randomized controlled crossover study. Intake of soy plus prebiotic resulted in greater reductions in LDL-C (-0.18 +/- 0.07 mmol/L, P = .042) and in ratio of LDL-C to high-density lipoprotein cholesterol (-0.28 +/- 0.11, P = .041) compared with prebiotic. In addition, high-density lipoprotein cholesterol was significantly increased on soy plus prebiotic compared with prebiotic (0.06 +/- 0.02 mmol/L, P = .029). Differences in bifidobacteria, total anaerobes, aerobes, and breath hydrogen did not reach significance. Soy foods in conjunction with a prebiotic resulted in significant improvements in the lipid profile, not seen when either prebiotic or soy alone was taken. Coingestion of a prebiotic may potentiate the effectiveness of soy foods as part of the dietary strategy to lower serum cholesterol.
authors.affiliation: Clinical Nutrition and Risk Factor Modification Center, St. Michael's Hospital, Toronto, Ontario, Canada M5C 2T2.
authors.forename: Julia M W
authors.initials: JM
authors.lastname: Wong
authors.forename: Cyril W C
authors.initials: CW
authors.lastname: Kendall
authors.forename: Russell
authors.initials: R
authors.lastname: de Souza
authors.forename: Azadeh
authors.initials: A
authors.lastname: Emam
authors.forename: Augustine
authors.initials: A
authors.lastname: Marchie
authors.forename: Ed
authors.initials: E
authors.lastname: Vidgen
authors.forename: Candice
authors.initials: C
authors.lastname: Holmes
authors.forename: David J A
authors.initials: DJ
authors.lastname: Jenkins
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004032:Diet; D005260:Female; D006801:Humans; D006949:Hyperlipidemias / Q000097:blood* / Q000178:diet therapy*; D008055:Lipids / Q000097:blood*; D008297:Male; D008875:Middle Aged; D056692:Prebiotics; D016037:Single-Blind Method; D045730:Soy Foods; D016896:Treatment Outcome
chemical_list: D008055:Lipids; D056692:Prebiotics