Soy isoflavone improves endothelial dysfunction

Recent study results suggest that the phytoestrogen isoflavone, which is present in soybeans, soy products, and chickpeas, may help to protect stroke patients from further cardiovascular events.

Professor Hung-Fat Tse of the University of Hong Kong and colleagues enrolled 102 people with established heart disease, and who had suffered a first or recurrent ischemic stroke within the previous six months, for their study to determine the effects of isoflavone on blood flow. Participants were randomly assigned to take either an isoflavone supplement (80 mg/day) or a placebo for 12 weeks.

Results showed that isoflavones increased flow-mediated dilatation (FMD) – an indicator of the functioning of the endothelial cells – therefore improving endothelial dysfunction, a key factor in the development of atherosclerosis. Isoflavone supplementation also significantly lowered levels of the inflammatory marker C-reactive protein. Thus suggesting that the alleviation of vascular inflammation is, to some degree, responsible for isoflavone's beneficial effects on endothelial function.

The researchers say that it is too early to recommend the use of isoflavones supplements; however they suggest that eating a diet containing plenty of isoflavone-rich foods may help to reduce ischemic risk in stroke patients.
 
Chan YH, Lau KK, Yiu KH, Li SW, Chan HT, Fong DYT, Tam S, Lau CP, Tse HF. Reduction of C-reactive protein with isoflavone supplement reverses endothelial dysfunction in patients with ischaemic stroke. Eur Heart J. Advance Access published on September 23, 2008; doi: doi:10.1093/eurheartj/ehn409.