Dietary Nitrate Showed No Significant Effect on 6 Outcomes in 45-Trial Athlete Review

A new meta-analysis pooled 45 placebo-controlled trials to test whether dietary nitrate improves athletic performance. Across six separate outcomes, dietary nitrate came back statistically indistinguishable from placebo.

Dietary nitrate supplementation produced no statistically significant effect on any of six performance and physiological outcomes in a systematic review of 45 randomised placebo-controlled trials, published on October 20, 2026 in Sports. The pooled sample comprised 659 trained athletes.

The review was led by Yiqing Xie of Loughborough University in the United Kingdom and Shanghai University of Sport in China, with Kai Xu of Shanghai University of Sport and Edith Cowan University in Australia as corresponding author. Co-authors Yemin Han and Qing Du are also at Shanghai University of Sport.

Beetroot juice and nitrate salts have been among the most widely used legal performance aids in endurance sport for well over a decade. The appeal is mechanistic: nitrate is converted to nitrite and then to nitric oxide, which influences blood flow and muscle efficiency.

This review asked whether that mechanism shows up as measurable performance in trained athletes specifically. On the pooled evidence, it does not.

What the Dietary Nitrate Review Pooled

The authors searched databases from inception to September 17, 2026. An initial search was completed on May 6, 2026 and re-run in September to capture newer trials. The protocol was registered on June 30, 2026, which the paper notes is after the first search and therefore retrospective.

Inclusion was restricted to randomised, placebo-controlled trials in healthy athletes at Tier 2 or above on standard participant-classification frameworks. That threshold matters. Much of the enthusiasm for dietary nitrate rests on studies in recreationally active people, who tend to respond more readily to ergogenic aids than trained competitors.

Six outcomes were analysed separately rather than combined into one performance index: peak power, mean power, VO2max, heart rate, blood lactate and ratings of perceived exertion. The authors treat them as distinct constructs, which is a more conservative approach than pooling them.

Six Outcomes, Six Null Results

The pooled estimates cluster tightly around zero. Peak power across 12 comparisons returned a Hedges g of 0.13, with a confidence interval from minus 0.07 to 0.32 and a p value of 0.20. Mean power across 17 comparisons gave g 0.04, interval minus 0.13 to 0.21, p 0.65.

VO2max, the most studied outcome with 26 comparisons, produced g minus 0.03, interval minus 0.20 to 0.15, p 0.77. Heart rate across 19 comparisons gave g minus 0.08, interval minus 0.27 to 0.10, p 0.38. Neither moved.

Blood lactate and perceived exertion were noisier. Lactate across 10 comparisons gave g 0.09 with a wide interval of minus 0.30 to 0.48, p 0.64. Perceived exertion across 9 comparisons gave g minus 0.17, interval minus 0.49 to 0.16, p 0.32.

Heterogeneity was negligible for the four power and cardiorespiratory outcomes, with I squared reported at zero percent for each. That is unusual and worth noting: the dietary nitrate trials broadly agreed with one another, and what they agreed on was an absence of effect.

The One Signal That Survived, and Why It Is Fragile

Subgroup analysis found a single positive result. In male-only studies, peak power favoured dietary nitrate with g 0.29 and a confidence interval of 0.02 to 0.56, p 0.04. Mixed-sex studies showed nothing, at g minus 0.04 and p 0.78.

The authors do not treat this as a finding. The interaction test comparing those subgroups was not statistically significant, which means the apparent sex difference could easily be noise. Reporting it as exploratory is the correct call.

A publication-bias adjustment weakens it further. Trim-and-fill analysis for peak power imputed five missing studies, and the adjusted pooled effect fell to g minus 0.01, with an interval from minus 0.22 to 0.20. The signal does not survive correction for the trials that may never have been published.

Beetroot Juice and Nitrate Salts Performed Alike

One practical question the review could address is whether the delivery form matters. For VO2max, the only outcome where enough trials allowed the comparison, beetroot juice and nitrate salts both failed to separate from placebo, and the difference between the two sources was not significant at p 0.90.

Sport type and exercise type produced no significant interactions either. Only mean power and VO2max had enough trials to test by sport, and no sport subgroup reached significance. For dietary nitrate, there is no identified population or protocol in this dataset that clearly responds.

How Much Confidence the Dietary Nitrate Evidence Carries

The authors applied GRADE ratings to each outcome, and the spread is informative. Certainty was moderate for VO2max and heart rate, low for peak power and mean power, and very low for blood lactate and perceived exertion.

That means the two most reliable null results are the aerobic ones. If a reader wants to know whether dietary nitrate raises VO2max in trained athletes, this review offers moderate-certainty evidence that it does not. The power outcomes remain more open simply because the evidence base is weaker.

Risk of bias was a recurring issue. Most included trials were rated as having some concerns under the RoB 2 tool, with reporting of random sequence generation and prospective registration singled out as weak points across the literature.

Why This Dietary Nitrate Review Reads Differently From Earlier Ones

Other recent syntheses have been more favourable. A scoping review of 31 randomised trials in highly trained and elite athletes, published in August 2026, concluded that beetroot-derived nitrate may enhance performance, particularly during high-intensity and anaerobic activities.

The two can be reconciled. A scoping review maps what the literature claims; a meta-analysis pools the numbers and asks whether the average effect is distinguishable from zero. Narrative conclusions often read more positively than pooled estimates of the same body of work.

This pattern recurs across supplement research. Our coverage of a caffeine trial in female sprinters found a roughly 1.5 percent gain over 30 metres, and reviews of essential amino acids for recovery and a yeast and whey protein blend for soreness landed on modest effects. A creatine trial without exercise added about 2.4 pounds of lean tissue.

What Athletes Can Reasonably Take From This

The honest reading is that dietary nitrate is not a reliable performance lever for trained athletes on current pooled evidence. That is a narrower claim than saying it never works for anyone. Trained populations respond less to most ergogenic aids, and this review was deliberately restricted to them.

A few general points follow, none of them individualised advice:

• Beetroot juice remains an ordinary vegetable product with no identified safety problem in these trials. The question here is efficacy, not risk.
• Effect sizes of the magnitude excluded by these confidence intervals are smaller than normal day-to-day variation in most field tests, so personal experiments are unlikely to detect them.
• Training structure, sleep and total energy intake move performance by far larger margins than any dietary nitrate protocol tested here.
• Anyone with kidney disease, anyone on nitrate-based medication, or anyone subject to anti-doping testing should check supplement decisions with a qualified clinician or sports dietitian first.

For most competitive athletes, the practical upshot is that dietary nitrate belongs in the category of plausible but unproven rather than established.