The effect of l-arginine supplementation on lipid profile: a systematic review and meta-analysis of randomised controlled trials
What this study found
L-arginine supplementation significantly reduced triglycerides, but it did not significantly change total cholesterol, LDL-cholesterol, or HDL-cholesterol. For triglycerides, the pooled effect was WMD -7.04 mg/dl (95% CI -11.42 to -2.67; P<0.001; I2=0.0%). Total cholesterol was WMD -5.03 mg/dl (95% CI -10.78 to 0.73; P=0.08), LDL-cholesterol was WMD -0.47 mg/dl (95% CI -3.61 to 2.66; P=0.76), and HDL-cholesterol was WMD 0.57 mg/dl (95% CI -1.28 to 2.43; P=0.54). The authors concluded that more well-designed trials are needed, especially in patients with dyslipidemia.
- Study & population
- Systematic review and meta-analysis of 10 randomized controlled trials with 13 active L-arginine arms.
- Intervention
- L-arginine supplementation was given orally as daily L-arginine, with doses ranging from 1 to 21 g/day for 4 to 77 weeks.
- Key limitation
- The evidence base was small and heterogeneous, with only 10 randomized trials, varied doses (1 to 21 g/day), and intervention durations ranging from 4 to 77 weeks.
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Open PDFOriginal abstract
Abstract A number of clinical trials have examined the effect of l-arginine on lipid profile in recent years; however, the results remain equivocal. Therefore, the present study aims to summarise and quantitatively examine the available evidence on the effectiveness l-arginine supplementation on lipid parameters using a systematic review and meta-analytic approach. Online databases including PubMed, Scopus, ISI Web of Science, Cochrane Library and Google Scholar were searched up to April 2019 for randomised controlled trials that examined the effect of l-arginine supplementation on lipid profile in adults. Treatment effects were expressed as weighted mean difference (WMD) and the corresponding standard error in concentrations of serum lipids. To estimate the overall effect of l-arginine supplementation, we used the random-effects model. In total, twelve studies were included in the systematic review. The meta-analysis revealed that l-arginine supplementation did not significantly change the concentrations of total cholesterol (WMD: –5·03 mg/dl; 95 % CI –10·78, 0·73; P = 0·08; inconsistency index (I2) = 39·0 %), LDL (WMD: –0·47 mg/dl; 95 % CI –3·61, 2·66; P = 0·76; I2 = 0·0 %), or HDL (WMD: 0·57 mg/dl; 95 % CI –1·28, 2·43; P = 0·54; I2 = 68·4 %). A significant reduction was observed only in serum TAG levels (WMD: –7·04 mg/dl; 95 % CI –11·42, –2·67; P < 0·001; I2 = 0·0 %). This meta-analysis concludes that l-arginine supplementation can significantly reduce blood TAG levels; however, there is insufficient evidence to support its hypocholesterolaemic effects. To draw straightforward conclusions regarding generalised recommendations for l-arginine supplementation for improving lipid profile, there is a need for more well-controlled trials targeting exclusively patients with dyslipidaemia.