Effect of food sources of nitrate, polyphenols, L-arginine and L-citrulline on endurance exercise performance: a systematic review and meta-analysis of randomised controlled trials
d'Unienville NMA, Blake HT, Coates AM, Hill AM
Published in Journal of the International Society of Sports Nutrition
Methodology
Systematic review and random-effects meta-analysis of 118 randomised controlled trials of nitrate-, polyphenol-, L-arginine- and L-citrulline-rich foods on endurance performance, with subgroup analyses by food source, sex, fitness and protocol
Key Findings
Nitrate-rich and polyphenol-rich foods produced trivial but statistically significant benefits (SMD 0.15 and 0.17, p<0.001) across time-trial, time-to-exhaustion and intermittent tests, while L-citrulline foods showed no effect (SMD -0.03, p=0.24).
Conclusions
Food-based nitric oxide precursors give small endurance gains at best, and L-citrulline shows no measurable benefit.
Limitations
High heterogeneity across 118 trials, varied dosing protocols and performance tests, mostly trained male participants.
Supplements Studied
No effect on exercise performance following consumption of foods rich in L-citrulline was identified (SMD=-0.03, p=0.24).
Outcomes Measured
Trivial but significant benefits were demonstrated for consumption of nitrate and polyphenol-rich foods (SMD=0.15 and 0.17, respectively, p<0.001)
Effect of food sources of nitrate, polyphenols, L-arginine and L-citrulline on endurance exercise performance
Study Details
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Disclosures
Funding
Academic/non-commercial
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