High blood pressure (BP), which is associated with millions of deaths per year, is thought to be the most important risk factor for heart failure with preserved ejection fraction, haemorrhagic stroke, and cognitive impairment.1,2 L-arginine is an amino acid that is acquired from dietary sources or endogenous metabolism. Previous research findings on the link between L-arginine supplementation and hypertension have varied, which may be due to several factors, including diverse BP categories, dosages, and durations.
A recent systematic review and dose-response meta-analysis of randomized clinical trials published in Advances in Nutrition (DOI: https://doi.org/10.1093/advances/nmab155) investigated the effect of L-arginine supplementation on blood pressure in adults.
Research was conducted through scientific databases including PubMed/Medline, Scopus, Web of Science, EMBASE, the Cochrane database, and Google Scholar. No restrictions were implemented on the length of time or language of publications. The 22 clinical trials included used oral intake of L-arginine, had at least a four-day intervention duration, included only adult humans (≥18 years old), and provided means and standard deviations for both systolic blood pressure (SBP) and diastolic blood pressure (DBP). These studies were published between 1996 and 2021 across 12 countries.
The studies comprised 431 participants in the intervention group and 394 in the placebo group for SBP. Across these publications, L-arginine supplementation significantly reduced SBP. Furthermore, except for the high dosage treatments (> 9 g/d), subgroup analysis revealed that L-arginine supplementation significantly lowered SBP across all subgroups.
For DBP, the populations included 392 participants in the intervention group and 361 in the placebo group. Pooled effect sizes showed a significant decrease in DBP. However, when a high dosage of L-arginine (> 9 g/d) was utilised, or in studies involving males, both sexes, and obese participants (>30 kg/m2), the subgroup analysis found that L-arginine supplementation had no effect on DBP.
The researchers suggest that “consuming low dosages of L-arginine (≤9 g/d) for a short-term (≤24 days) is more effective than consuming higher dosages for longer durations. L-arginine is beneficial for healthy and unhealthy individuals, hypertensive and normotensive, in all BMI categories, and regardless of sex, but especially favorable for women.” There were also no major side effects of L-arginine supplementation across the reviewed studies.
References
1. Flegal KM, Carroll MD, Ogden CL, Johnson CL. Prevalence and trends in obesity among US adults, 1999-2000. Jama. 2002 Oct 9;288(14):1723-7.
2. Forouzanfar MH, Liu P, Roth GA, Ng M, Biryukov S, Marczak L, Alexander L, Estep K, Abate KH, Akinyemiju TF, Ali R. Global burden of hypertension and systolic blood pressure of at least 110 to 115 mm Hg, 1990-2015. Jama. 2017 Jan 10;317(2):165-82.
