The Effect of Oral L-arginine Supplementation on Blood Pressure in Patients with Metabolic Syndrome: A Randomized Clinical Trial

Objective: Hypertension is a common component of metabolic syndrome (MetS). Some studies showed that L-arginine reduced the blood pressure (BP) .Therefore this study was designed to evaluate the effect of L-arginine supplementation on BP in MetS. Materials and Methods: In this randomized, double-blind, placebo-controlled trials, 60 patients with MetS were randomly divided into two groups: the L-arginine-supplemented group (AG), who received 5 gr of L-arginine daily and placebo group (PG). Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), pulse pressure (PP) were measured before and after the intervention and compared. Results: At the end of the study in the AG significant reductions were observed in the SBP, DBP and MAP (P-value:0.001).The comparison of changes in variables between the AG and PG indicated that in the AG, patients had a significantly greater decrease in the SBP (-11.25±10.93 vs. -2.67±6.15 mmHg: P-value:0.001), DBP(-5.71±7.16 vs. -1.25±7.02 mmHg: p-value: 0.02) and MAP (-7.55±5.61 vs.-1.72±5.16 mmHg, P-value: 0.001). The PP decreased in both groups but a significant decrease compared with baseline in the AG was observed (-5.53±13.83 vs. -1.42±9.21 mmHg: P-value: 0.19). Conclusion: The findings of the present study showed that 5 gr/d L- arginine supplementation for 12 weeks in MetS resulted in significant decrease in the SBP, DBP and MAP but had no significant effect on the PP.