Abshirini M, et al. - Researchers determined whether soy protein supplement containing isoflavones could impact endothelial function in postmenopausal women, by analyzing relevant randomized controlled trials (RCTs) in this systematic review and meta-analysis. PubMed-Medline, SCOPUS, Embase, and Google Scholar were explored to identify the relevant RCTs. A systematic review including 15 studies and a meta-analysis comprising 5 studies was conducted. Findings revealed that no meaningful improvement in flow-mediated dilation was conferred by soy protein supplementation in postmenopausal women. However, this revelation was based on a limited number of studies. There is a need for additional high-quality large-scale RCTs.