The large body of literature on human clinical trials of soy proteins and isoflavones has focused primarily on traditional lipid and lipoprotein parameters, biomarkers of CVD risk, and functional changes in endothelial function, platelet activation and total blood antioxidant capacity as described above. It is possible and likely that the effect of soy consumption on CVD risk is a net result of multiple subtle changes in metabolic pathways, vascular inflammatory responses and cell-signaling pathways which are not readily detected in healthy individuals. Since individuals with metabolic syndrome (MetS) present with many of the metabolic aberrations purported to be improved through soy food ingestion, these individuals may be an excellent study population in order to investigate the effects of a soy food intervention on metabolic markers of health. Equol is the end-product of daidzein biotransformation, and is produced only by some humans, resulting in a phenotypic characteristic in response to dietary soy. It is hypothesized by some researchers that the "equol producers" may have additional metabolic and phenotypic responses to soy which may help to explain some of the variances in the literature. Few investigators have examined this question in existing studies, with two reporting an association with outcomes and one no association. A recent study using microarray analysis of lymphocytes from postmenopausal women demonstrated differential gene expression in women who form equol compared to those who do not, suggesting that equol status may be an important modulator of responses to soy isoflavones. No studies have examined this question in a metabolomic investigation. This demonstrates a gap in the literature and provides an opportunity to contribute significant novel data using cutting-edge approaches.