Potential blood pressure lowering effect of L-citrulline supplementation in at risk populations: a meta-analysis

Abstract

Purpose This paper aims to investigate the effect of L-citrulline supplementation on blood pressure (BP) in middle-aged and elderly populations. Design/methodology/approach Three electronic databases, namely, Google Scholar, PubMed and Scopus, were searched from 1990 to November 2020. Random effects model analysis was applied for quantitative data synthesis, and 6 trials with 150 participants were identified and included in the analysis. Findings Results showed an overall non-significant effect of L-citrulline supplementation on both systolic BP (SBP) and diastolic BP (DBP) in middle-aged and elderly participants. However, stratified analysis indicated a significant reduction in SBP (SMD: −0.41, 95% CI: −0.84, 0.02; p = 0.06, heterogeneity p = 0.41; I2 = 10%) but not in DBP (SMD:−0.15, 95% CI: −0.57, 0.28; p = 0.51, heterogeneity p = 0.60; I2 = 0%), following longer-term (= 8 weeks) supplementation of L-citrulline. Additionally, higher doses of L-citrulline (= 6 grams) showed a marginally significant reduction in DBP (SMD: −0.38, 95% CI: −0.78, 0.02; p = 0.06, heterogeneity p = 0.50; I2 = 0%). Originality/value In conclusion, a higher dosage and longer duration of supplementation with L-citrulline may have potential BP lowering effects in populations at an increased risk of hypertension