Effects of black soy peptide supplementation on blood pressure and oxidative stress: a randomized controlled trial

Abstract

Black soy peptides have been shown to possess properties that may decrease blood pressure (BP). To examine the effects of black soy peptide supplementation on BP and oxidative stress in subjects with prehypertension or stage I hypertension, 100 participants with an initial untreated systolic blood pressure (SBP) of 130-159 mm Hg, diastolic blood pressure (DBP) of 80-99 mm Hg or both were enrolled. Participants were randomly assigned to either a group ingesting supplement containing 4.5 g black soy peptides daily or a placebo group for 8 weeks. SBP and DBP decreased after 8-week black soy peptide supplementation versus controls (P<0.001). At 8 weeks, SBP decrease was significantly greater for the black soy peptide group (-9.69 ± 12.37 mm Hg) than for the control group (-2.91 ± 13.29 mm Hg) after adjusting for the baseline levels (P = 0.015). Plasma malondialdehyde (MDA) and urinary 8-epi-prostaglandin F2α decreased (P = 0.004 and P = 0.046, respectively) and plasma superoxide dismutase (SOD) activity increased (P<0.001) following 8 weeks of black soy peptide supplementation versus baselines. The MDA decreases (P = 0.022) and SOD activity and nitric oxide (NO) increases (P = 0.022 and P<0.001, respectively) were greater for the black soy peptide group than for the control group. Changes in SBP negatively correlated with changes in NO (r = -0.343, P = 0.001). Changes in angiotensin-converting enzyme activity negatively correlated with NO decreases (r = -0.490, P<0.001) and SOD activity increases (r = -0.338, P = 0.001). Black soy peptide dietary supplementation significantly reduces SBP and oxidative stress in patients with prehypertension and stage I hypertension.

Enriching plausible new hypothesis generation in PubMed

“…We specifically confirmed a strongly negative correlation between total NO and plasma MDA, a marker of oxygen-derived free radicals, was consistent with a previous report [42]. Bioavailability of NO is a critical factor to maintain normal vascular functions including vasomotor reactivity, anti-thrombosis state, barrier function and non-adhesive state to inflammation cells [43].…”

The Effect of Soy Nuts on Glycemic Control, Lipid Profile and Insulin-Resistance in Type 2 Diabetic Patients

“…In another study, Kwak et al showed that soy consumption for 12 weeks improved fasting and 2-hour blood glucose in type 2 diabetic patients compared to control group, but did not have any significant effect on reducing the level of HbA1c [11]. A Meta-analysis performed by Reynolds et al confirmed, the positive effect of the soy consumption on total cholesterol, LDL-c, TG and HDL-c [12] that is in concordance with our finding.…”

Soy Consumption with Risk of Coronary Heart Disease and Stroke: A Meta-Analysis of Observational Studies

“…Soy products are typically low in saturated fat and high in unsaturated fatty acids, soy protein, isoflavones and water-soluble fiber, and a number of reports have indicated beneficial effects of soy consumption on CVD and its intermediate biomarkers such as blood cholesterol [3,22] , blood pressure [2,23] , hyperglycemia, diabetes mellitus (DM) [4,[24][25][26] , and obesity [25] . Furthermore, mechanistic studies have demonstrated anti-atherosclerotic effects of soy components through various mechanisms such as cellular vasodilation, anti-platelet aggregation [26,27] , inhibition of proliferation and migration of vascular smooth muscle cells [27,28] , cholesterolemia-lowering effects, antioxidant effects [28,29] and reduction in adhesion molecules [29,30] .…”