Another important mechanism through which soya isoflavones may improve cardiovascular disease is the effect they may have on platelets.
Studies on animals have suggested that isoflavones may inhibit platelet activation and aggregation and reduce the amount of serotonin in the platelets, all of which could contribute to a reduction in coronary vasospasm and thrombosis (1-3).
Studies in humans showed that soya protein and isoflavones exert effects on the blood to decrease the risk of clot formation. Soya protein inhibits a primary step in blood clot formation by reducing platelet aggregation or “clumping” (4).
Evidence has been found that the isoflavones seem to decrease the tendency of the formation of thromboses in the blood, which reduces the risk of thrombotic occlusion of the blood vessel (5).
Another risk factor for thrombosis formation is elevated serum homocysteine levels. Soya protein intake is associated with decreases in serum homocysteine values (6,7).
This means that consumption of soya protein rich in isoflavones decrease the risk of clot formation in two ways, by inhibiting the first step in the clot formation process and by decreasing serum homocysteine levels.
References :
- Williams JK&Clakson TB.Dietary soy isoflavones inhibit in-vivo constrictor responses of coronary arteries to collagen-induced platelet activation.Coron Artery Dis 1998;9(11):759-764
- Schoene NW & Guidry CA. Dietary soya isoflavones inhibit activation of rat platelets.J Nutr Biochem 1999;10:421-426
- Helmeste DM & Tang SW. Tyrosine kinase inhibitors regulate serotonin uptake in platelets.Eur J Pharmacol 1995 Jul 4;280(2):R5-R7.
- Gooderham JM, Adlercreutz H, Ojala S, Wahala K, Holub BJ. A soy protein isolate rich in genistein and daidzein and its effects on plasma isoflavone concentrations, platelet aggregation, blood lipids and fatty acid composition of plasma phospholipid in normal men. J Nutr 1996; 126: 2000-6
- Wilcox JN, Blumenthal BF. Thrombotic mechanism in atherosclerosis: potential impact of soy proteins. J Nutr 1995; 125: 631S-8S
- Hermansen K, Soondergaard M, Hoie L, Carstensen M, Brock B. Beneficial effects of a soy-based dietary supplement on lipid levels and cardiovascular risk markers in type 2 diabetic subjects. Diabetes Care 2001; 24: 228-33
- Jenkins DJA, Kendall CWC, Jackson CJ et al. Effects of high- and low-isoflavone soyfoods on blood lipids, oxidized LDL, homocysteine, and blood pressure in hyperlipidemic men and women. Am J Clin Nutr 2002; 76: 365-72