Background/Objective: To investigate the effect of soy protein containing isoflavones on homocysteine (Hcy), C-reactive protein (CRP), soluble E-selectin (sE-selectin), soluble vascular adhesion molecule-1 (sVCAM-1) and soluble intercellular adhesion molecule-1 (sICAM-1). Subject/Methods: In a randomized crossover design, 34 postmenopausal women consumed soy protein isolate (26±5 g protein containing 44±8 mg isoflavones per day) or milk protein isolate (26±5 g protein per day) for 6 weeks each. Fasting blood samples were collected at the end of each diet period and end points analyzed by enzyme-linked immunosorbent assay. Results: Concentrations of Hcy, CRP, sE-selectin, sVCAM-1 and sICAM-1 were not different between soy and milk diet treatments. Results did not differ by equol production status or by baseline lipid concentration. Adjustment for intake of folate and methionine did not alter the Hcy results. Conclusions: These data suggest that decreasing vascular inflammation and Hcy concentration are not likely mechanisms by which soy consumption reduces coronary heart disease risk.
Bibliographical noteFunding Information:
This study was supported by the United States Army Department of Defense Grant DAMD17-99-1-9297, General Clinical Research Center Grant M01-RR00400 from the National Center for Research Resources, the Minnesota Agricultural Station and the Solae, St Louis, MO, USA. Protein powders were provided by the Solae.