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Effect of L-citrulline intake on blood pressure in cold environments: A systematic review and meta-analysis of randomized controlled trials

cardiology
evidence-based-medicine
nutrition
public-health
environmental-health

Abstract

Background/Objectives: This study employs systematic review and meta-analysis to integrate existing evidence from Randomized Controlled Trials (RCTs), aiming to evaluate the regulatory effect of L-citrulline supplementation on blood pressure (BP) under cold exposure conditions, to provide evidence-based support for cardiovascular health interventions in low-temperature environments.

Methods: A comprehensive search was performed across four major databases (PubMed, Cochrane, Embase, and Web of Science) from their inception to May 28, 2025. Using RevMan 5.4.1 software, a random-effects model was applied to combine effect sizes for the obtained systolic blood pressure (SBP) and diastolic blood pressure (DBP) data, with results reported as weighted mean difference (WMD) and 95% confidence interval (95% CI).

Results: A total of 6 RCTs investigating the effects of L-citrulline intake on BP in cold environments were included, involving 162 participants (intervention group: 87; control group: 75). Results indicate that L-citrulline intake significantly reduced cold-induced SBP (-9.16 mmHg [95% CI: -10.70 to -7.63], P < 0.00001) and DBP (-5.50 mmHg [95% CI: -8.88 to -2.13], P = 0.001). Subgroup analysis revealed significant reductions in brachial SBP (-8.97 mmHg [95% CI: -11.45 to -6.49], P < 0.00001), aortic SBP (-9.20 mmHg [95% CI: -11.38 to -7.03], P < 0.00001), and aortic DBP (-6.51 mmHg [95% CI: -10.50 to -1.80], P = 0.006). However, brachial DBP reduction did not reach statistical significance but showed a trend toward decrease (-4.85 mmHg [95% CI: -10.20 to 0.50], P = 0.08).

Conclusions: Supplementation with L-citrulline effectively alleviates cold-induced BP elevation and significantly reduces both SBP and DBP, indicating its potential clinical value in assisting BP management under cold climate conditions.
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