Isoflavones reduce arterial stiffness: a placebo-controlled study in men and postmenopausal women.

Objective: This study was undertaken to address the vascular effects of isolated isoflavones as potential contributors to their cardioprotective properties, focusing on biochanin and formononetin.

Methods And Results: In a randomized, double-blind trial, 80 healthy subjects, 46 men and 34 women, 45 to 75 years of age, received isoflavones enriched in either biochanin or formononetin (precursors of genistein and daidzein; 80 mg/d) crossed over randomly with placebo in two 6-week periods. The end points were measured at baseline and after each intervention and included large artery stiffness (systemic arterial compliance and pulse wave velocity), endothelial function in conduit arteries (flow-mediated vasodilation), 24-hour ambulatory blood pressure, and total peripheral resistance.