Effects of soy protein on endothelium-dependent vasodilatation and lipid profile in postmenopausal women with mild hypercholesterolemia.

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.

Effects of oral soy protein on markers of inflammation in postmenopausal women with mild hypercholesterolemia.

Background: Nitric oxide (NO) may protect arteries against atherosclerosis, as suggested by experimental studies. Estrogen therapy enhances the bioactivity of NO in the vasculature of healthy postmenopausal women, but is not acceptable for long-term use by many women. Observational studies have demonstrated beneficial cardiovascular effects of soy protein in premenopausal and postmenopausal women.