Soy Compound Helps to Lower Blood Pressure

Affecting an estimated 1 billion people worldwide, hypertension (high blood pressure) is a primary risk factor in the development of cardiovascular disease.  As dietary interventions can serve as an important approach to prevent and treat hypertension, some previous studies have suggested that soy isoflavones help to widen blood vessels, improve artery function, and decrease blood pressure.  X. Liu, from Peking Union Medical College and Chinese Academy of Medical Sciences (China), and colleagues conducted a meta-analysis of 11 published studies involving the effect of soy isoflavones on blood pressure.  Across the studies, the team found that consumption of between 65 and153 milligrams of soy isoflavones with soy protein per day, for up to 12 months,  lowered blood pressure among hypertensive subjects by 5.9 mmHg.  The researchers then completed a subgroup analysis according to blood pressure status, where subjects were divided into two subcategories: hypertensive [high blood pressure] populations (5 studies) and normotensive [normal blood pressure] populations (6 studies).  They found that the reduction in blood pressure was greater in isoflavone-treated subjects, as compared to placebo counterparts in the hypertensive group; as well, no significant differences were observed in blood pressure between subjects treated with soy isoflavones or placebo in the normotensive participants. The team concludes that: “Soy isoflavones had an effect of lowering blood pressure in hypertensive subjects, but not in normotensive subjects.”

X.X. Liu, S.H. Li, J.Z. Chen, K. Sun, X.J. Wang, X.G. Wang, R.T. Hui.  “Effect of soy isoflavones on blood pressure: A meta-analysis of randomized controlled trials.”  Nutrition, Metabolism and Cardiovascular Diseases, 9 February 2011.