Effect of L-citrulline supplementation on blood pressure: a systematic review and meta-analysis of randomized controlled trials

Area of Science:

• Cardiovascular Research
• Nutritional Science
• Pharmacology

Background:

• Hypertension is a major global health concern.
• Dietary interventions are increasingly explored for blood pressure management.
• L-citrulline is an amino acid found in certain foods, known for its role in nitric oxide synthesis.

Purpose of the Study:

• To systematically evaluate the efficacy of oral L-citrulline supplementation on systolic and diastolic blood pressure.
• To synthesize data from multiple clinical trials using meta-analysis.
• To identify factors influencing L-citrulline's blood pressure-lowering effects.

Main Methods:

• Systematic literature search of electronic databases up to April 2018.
• Inclusion of 15 trials involving 424 participants.
• Combined and stratified meta-analyses to assess treatment effects.

Main Results:

• Oral L-citrulline or watermelon extract significantly reduced systolic blood pressure by -7.54 mmHg and diastolic blood pressure by -3.77 mmHg.
• Subgroup analyses indicated greater efficacy with study durations of ≥6 weeks, doses ≤4 g/day, and in participants with baseline blood pressure ≥130/85 mmHg.
• No significant changes were observed in control groups.

Conclusions:

• Oral L-citrulline supplementation effectively improves both systolic and diastolic blood pressure.
• The blood pressure-lowering effect appears more pronounced in individuals with pre-hypertension or hypertension.
• L-citrulline represents a potential nutritional strategy for managing elevated blood pressure.