L-arginine Benefits Vascular Health

BEIJING—In a recent Chinese study, short-term oral L-arginine effectively improved the fasting vascular endothelial function when the baseline flow-mediated dilation (FMD) was low (Am J Clin Nutr. 2009;89(1):77-84). Researchers conducted a meta-analysis of randomized, placebo-controlled L-arginine supplementation trials that evaluated endothelial function. Thirteen trials were included and evaluated. Because there was only one long-term study, researchers focused on short-term effects of L-arginine (12 studies, 492 participants). In an overall pooled estimate, L-arginine significantly increased FMD (P=0.01). Meta-regression analysis indicated the baseline FMD was inversely related to effect size (P=0.016). A subgroup analysis suggested L-arginine supplementation significantly increased FMD when the baseline FMD levels were less than 7 percent (P=0.003), but had no effect on FMD when baseline FMD was greater than 7 percent (P=0.67).