Acute inorganic nitrate ingestion does not impact oral microbial composition, cognitive function, or high-intensity exercise performance in female team-sport athletes.
Level 2 - randomized trial
Individual randomized double-blind crossover trial
PubMed 39017740 · doi:10.1007/s00421-024-05552-w
What was done
Fifteen female team-sport athletes participated in a randomized, double-blind, crossover trial comparing acute ingestion of nitrate-rich beetroot juice (BR; 12.0 mmol NO3-) against a nitrate-depleted placebo (PL; 0.1 mmol NO3-) consumed 2.5 hours prior to testing. Outcomes measured before and after a Yo-Yo intermittent recovery level 1 (YYIR1) test included oral microbiota composition, cognitive flexibility, 10-m and 20-m sprint times, isokinetic handgrip dynamometry, medicine ball throw, and horizontal countermovement jump performance.
What was found
BR significantly elevated resting plasma nitrate and nitrite concentrations compared to placebo (P < 0.001). However, BR had no significant effect on oral microbiome composition or taxa abundance (P > 0.05) or cognitive flexibility (P > 0.05). Performance measures did not differ between conditions (P > 0.05), including 20-m sprint (PRE, PL: 4.38 ± 0.27 vs. BR: 4.38 ± 0.32 s; POST, PL: 4.45 ± 0.29 vs. BR: 4.43 ± 0.35 s), 10-m sprint (PRE, PL: 2.78 ± 0.15 vs. BR: 2.79 ± 0.18 s; POST, PL: 2.82 ± 0.16 vs. BR: 2.81 ± 0.19 s), YYIR1 distance (PL: 355 ± 163 m vs. BR: 368 ± 184 m), handgrip strength, medicine ball throw, or jump distance.
Why it matters
This study suggests that acute dietary nitrate supplementation may not provide ergogenic or cognitive benefits for intermittent high-intensity exercise in trained female team-sport athletes, despite successfully elevating circulating nitric oxide precursors.
Limits
The sample size was small (n = 15) and restricted strictly to female team-sport athletes, limiting generalizability. The study examined only acute single-dose supplementation, leaving open whether multi-day or chronic dosing protocols might yield different physiological, microbial, or performance outcomes.
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