title: Effect of soy isoflavone protein and soy lecithin on endothelial function in healthy postmenopausal women.
abstract: OBJECTIVE
  To assess the effects of soy isoflavone protein concentrate and soy lecithin on endothelial function, measured as flow-mediated dilation (FMD) of the brachial artery in healthy postmenopausal women.
  
  
  METHODS
  This was a randomized, double-blind, placebo-controlled crossover trial with 25 participants (mean age, 61 years; body mass index, 25.46 kg/m2). The women underwent endothelial function testing at baseline and after 4 weeks of randomly assigned treatment with intervening 4-week washout periods. Treatment assignments included soy isoflavone protein (25 g/day) and soy lecithin (20 g/day), soy isoflavone protein (25 g/day) and placebo lecithin, placebo protein and soy lecithin (20 g/day), and double placebo. FMD and serum lipid levels were assessed at baseline and the end of each 4-week treatment phase.
  
  
  RESULTS
  Twenty-two women completed the trial. No statistically significant (P > 0.05) difference was seen in FMD between treatment groups. A trend was suggested with FMD highest after treatment with soy protein plus lecithin (7.50 +/- 9.85), followed by soy protein (5.51 +/- 10.11), soy lecithin (5.35 +/- 6.13), and lowest after placebo (4.53 +/- 7.84). Soy isoflavone protein and soy lecithin significantly increased the high-density lipoprotein/low-density lipoprotein ratio (soy isoflavone protein plus soy lecithin, 0.64 +/- 0.19, P < 0.0001; soy isoflavone protein plus placebo lecithin, 0.58 +/- 0.17, P = 0.0058; placebo protein plus soy lecithin, 0.65 +/- 0.18, P < 0.0001) relative to the baseline value (0.49 +/- 0.15).
  
  
  CONCLUSIONS
  In this sample of healthy postmenopausal women, soy isoflavone protein and soy lecithin significantly improved the lipid profile. A favorable influence on endothelial function could not be confirmed.
authors.affiliation: Yale Prevention Research Center, Derby, CT 06418, USA.
authors.forename: Marian
authors.initials: M
authors.lastname: Evans
authors.forename: Valentine Yanchou
authors.initials: VY
authors.lastname: Njike
authors.forename: Martha
authors.initials: M
authors.lastname: Hoxley
authors.forename: Meghan
authors.initials: M
authors.lastname: Pearson
authors.forename: David L
authors.initials: DL
authors.lastname: Katz
mesh_terms: D000368:Aged; D001916:Brachial Artery / Q000502:physiology; D002794:Choline / Q000097:blood; D004311:Double-Blind Method; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology; D005260:Female; D006801:Humans; D007529:Isoflavones / Q000097:blood / Q000494:pharmacology*; D008074:Lipoproteins / Q000097:blood; D008875:Middle Aged; D017698:Postmenopause / Q000097:blood / Q000187:drug effects* / Q000502:physiology; D030262:Soybean Proteins / Q000494:pharmacology*; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D007529:Isoflavones; D008074:Lipoproteins; D030262:Soybean Proteins; D002794:Choline