title: Effects of soy protein on endothelium-dependent vasodilatation and lipid profile in postmenopausal women with mild hypercholesterolemia.
abstract: BACKGROUND
  Estrogens appear to improve endothelium-dependent systemic and coronary vasodilator function, perhaps by increasing nitric oxide levels and the subsequent effect of nitric oxide on endothelial function and smooth-muscle relaxation. Because soybean foods contain phytoestrogens, we evaluated the effect of orally administered soy proteins on vascular responsiveness.
  
  
  METHODS
  This double-blind, placebo-controlled crossover study involved 24 postmenopausal women (mean age 55 yr) who were hypercholesterolemic, who were not taking hormone replacement therapy and had not taken antioxidants or lipid-lowering agents in the preceding 2 months. The patients were randomized to receive a 25-g soy protein supplement or a mild protein placebo for 6 weeks, separated by a washout period of 4 weeks. To evaluate nitric oxide bioactivity we used ultrasonography to measure endothelium-dependent dilator responses in the brachial artery to hyperemia. We induced hyperemia by inflating a blood pressure cuff on the forearm to 250 mm Hg for 5 minutes. We also determined the effect of the supplements on various lipids.
  
  
  RESULTS
  The mean (+/- standard deviation) brachial artery diameter was similar in both groups (3.94 [0.79] mm in the placebo group and 4.13 [0.74] mm in the soy protein group). In both placebo and protein groups, the serum triglyceride levels increased, and total cholesterol and low-density lipoprotein cholesterol levels fell significantly (p < 0.05). High-density lipoprotein cholesterol levels were little changed.
  
  
  CONCLUSIONS
  Consumption of a supplement of 25 g of soy protein daily for 6 weeks had no measurable effect on arterial diameter or vasodilatation in response to hyperemia.
authors.affiliation: Department of Internal Medicine A, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel. navablum@hotmail.com
authors.forename: Arnon
authors.initials: A
authors.lastname: Blum
authors.forename: Nesia
authors.initials: N
authors.lastname: Lang
authors.forename: Fiona
authors.initials: F
authors.lastname: Vigder
authors.forename: Pnina
authors.initials: P
authors.lastname: Israeli
authors.forename: Marina
authors.initials: M
authors.lastname: Gumanovsky
authors.forename: Sacha
authors.initials: S
authors.lastname: Lupovitz
authors.forename: Andrea
authors.initials: A
authors.lastname: Elgazi
authors.forename: Aviva
authors.initials: A
authors.lastname: Peleg
authors.forename: Moshe
authors.initials: M
authors.lastname: Ben-Ami
mesh_terms: D002784:Cholesterol / Q000378:metabolism; D008078:Cholesterol, LDL / Q000378:metabolism; D018592:Cross-Over Studies; D019587:Dietary Supplements; D004311:Double-Blind Method; D004730:Endothelium, Vascular / Q000378:metabolism*; D005260:Female; D006801:Humans; D006937:Hypercholesterolemia / Q000188:drug therapy; D050356:Lipid Metabolism; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism; D010919:Placebos; D017698:Postmenopause; D030262:Soybean Proteins / Q000494:pharmacology*; D013997:Time Factors; D014463:Ultrasonography
chemical_list: D008078:Cholesterol, LDL; D010919:Placebos; D030262:Soybean Proteins; D009569:Nitric Oxide; D002784:Cholesterol