The effect of oral L-arginine supplementation on lipid profile, glycemic status, and insulin resistance in patients with metabolic syndrome: A randomized, double-blind, placebo-controlled trial

INTRODUCTION: The impressive growth in the incidence of metabolic syndrome (MetS) as well as the risk of its complications implies the need to focus on finding new ways to control such conditions. The present study was conducted to examine the effect of L-arginine supplementation on the lipid profile, glycemic status, and insulin resistance in patients with the MetS. METHODS: In this randomized double-blind, placebo-controlled trial, 60 patients with MetS were randomly divided into a placebo group (PG) and an arginine group (AG). The AG members received 5 g/d of L-arginine. The triglyceride (TG) levels, high-density lipoprotein cholesterol (HDL-c) and low-density lipoprotein cholesterol (LDL-c) values, total cholesterol (TC), hemoglobin A1c(HbA1c), fasting blood glucose (FBG), insulin, homeostasis model assessment of insulin resistance(HOMA-IR), quantitative insulin sensitivity check index(QUICKI), beta-cell function (beta%), and insulin sensitivity were measured at baseline and after 3 months of intervention. RESULTS: The results showed that the change in the AG in the TG levels (-20.92 +/- 22.2 mg/dl) was significantly greater than in the PG (-3.57 +/- 15.6 mg/dl; P = 0.001). The change in the ratio of cholesterol/HDL-c (-0.20 +/- 0.37) in the AG was also significantly greater than in the PG (0.12 +/- 0.69; P = 0.03). There was a significantly greater decrease (P = 0.001) in the FBG in the AG (-11.32 +/- 9.36 mg/dl) compared with the FBG in the PG (-1.57 +/- 7.96 mg/dl). CONCLUSIONS: The study showed that the daily supplementation of 5 g/d L-arginine for 12 weeks in patients with MetS significantly decreased the levels of FBG and TG, and the ratio of cholesterol/HDL-c. Thus, L-arginine can be useful in these patients.