Objective: To compare the effects of raloxifene and soy phytoestrogens on endothelial function in healthy, postmenopausal women.
Design: Randomized, double-blind, placebo-controlled, cross-over trial. Subjects (n = 22; mean age 58.5 years) underwent endothelial function testing at baseline and following 6 weeks of daily raloxifene 60 mg, soy phytoestrogens 55 mg, and placebo in random sequence with intervening 6-week wash-out periods. Endothelial function was assessed as flow-mediated vasodilatation (FMD) of the brachial artery using high-resolution ultrasound; digital flux was measured with laser Doppler velocimetry.
Results: Baseline (pretreatment) FMD was almost within normal range at 9.6% (+/-6.4). FMD did not change from baseline within any treatment group, and no between-group differences were detected. FMD values following treatment with raloxifene, soy, and placebo were 10.3% (+/-12.3), 8.3% (+/-7.7), and 9.5% (+/-4.4), respectively. Area under curve ratios showed no treatment differences for digital velocimetry.
Conclusions: In this study, neither raloxifene nor soy enhanced endothelial function in postmenopausal women. However, the cohort had relatively normal endothelial function at baseline. Further study is required to determine if particular subgroups of postmenopausal women derive vascular benefit from the use of selective estrogen receptor modulators or soy phytoestrogens.