Phytoestrogens do not influence lipoprotein levels or endothelial functionin healthy postmenopausal women

Plant estrogen or phytoestrogens (PE) are increasingly consumed for the pur poses of menopause symptom relief and prevention of cardiovascular and othe r diseases. The objective of this study was to evaluate the effects of PE o n plasma lipids and lipoproteins and on endothelial function. Twenty health y, postmenopausal women, 50 to 70 years old, and with evidence of endotheli al dysfunction, were treated with a soybean PE tablet of 80 mg/day of isofl avones, Endothelial function was assessed noninvasively using brachial ultr asound. A double-blind, placebo-controlled, randomized crossover design was employed. After 3 weeks stabilization on a standard fat-reduced diet, subj ects received PE or placebo for 8 weeks in random order, separated by a was hout period of 8 weeks. Compared with placebo, there were no significant ef fects of PE on blood pressure and plasma lipid or lipoprotein concentration s. Flow-mediated endothelium-dependent dilation (FMD) in response to reacti ve hyperemia was not significantly changed by PE ingestion (3.3 +/- 0.7% on placebo vs 4.1 +/- 0.7% on PE, p > 0.4). Variation in FMD was not correlat ed with change in plasma isoflavone concentration (r = -0.09, p > 0.7), Gly ceryl trinitrate endothelium-independent dilation was not significantly cha nged with PE (15.9 +/- 1.3% vs 13.7 +/- 1.2%, p > 0.1). These results fail to show a significant impact of medium-term supplementation with 80 mg/day of isoflavones on lipid and lipoprotein levels or on endothelial function i n healthy, postmenopausal women. (C) 2000 by Excerpta Medica, Inc.