The effect of nitrate supplementation on exercise performance in healthy individuals: a systematic review and meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of controlled human trials
PubMed 23580439 · doi:10.1123/ijsnem.23.5.522
What was done
Systematic review and meta-analysis of 17 controlled human studies evaluating the effect of inorganic nitrate supplementation (predominantly beetroot juice and sodium nitrate at doses of 300 to 600 mg, given as a single bolus or up to 15 days of ingestion) on exercise performance in healthy individuals.
What was found
Nitrate supplementation yielded a statistically significant moderate benefit for time to exhaustion tests (ES = 0.79, 95% CI: 0.23-1.35, p = .006). Effects were small and not statistically significant for time trials (ES = 0.11, 95% CI: -0.16-0.37) and graded exercise tests (ES = 0.26, 95% CI: -0.10-0.62). Qualitative analysis suggested benefits occurred more often in inactive to recreationally active participants and following chronic multi-day loading.
Why it matters
This review shows that dietary nitrate moderately improves endurance capacity in constant-load time-to-exhaustion tasks, but clear evidence for time-trial performance improvements remains lacking.
Limits
Total participant count across the 17 included studies was not reported in the abstract. Interventions showed substantial heterogeneity in supplement type, dosage, and duration (acute single bolus vs. 15 days). Performance improvements were not statistically significant in time trial or graded exercise test paradigms.
Cited by
- supports Beetroot juice acts as a vasodilator via nitric oxide pathways and enhances endurance performance, especially in steady-state endurance sports like cycling, swimming, and running.