Nitrates to Improve Cognitive Performance

Alongside traditionally popular dietary supplements such as protein, creatine and caffeine, other options have received less attention despite their proven effectiveness—at least so far. Nitrates are one example. Their benefits have been documented in scientific research for more than a decade, but only in recent years have they become prominent among sports consumers.

As discussed in a previous post, nitrate supplements work by stimulating nitric oxide, a substance whose main action is vasodilation—increasing blood flow and thereby tissue oxygenation.¹ This action has important effects in muscle, and nitrate supplementation has been shown to improve performance in different forms of exercise, including endurance, strength and power.^{2 3}

 Nitrates and Cognitive Performance in the General Population

This vasodilation may occur not only in muscle but also in the brain, improving cerebral blood flow and oxygenation of tissues involved in cognitive tasks, such as the frontal cortex. Numerous studies have therefore assessed the potential cognitive-performance benefits of nitrate supplementation, with promising results. Almost ten years ago, for example, a study of 30 participants with an average age of 60 found that long-term supplementation—10 weeks—with two different nitrate doses, 80 or 160 mg per day, improved not only physical-function tests such as handgrip strength and time to fatigue in an incremental test, but also reduced the time required to complete several cognitive-function tests (Figure 1).⁴

Figure 1. The time required to complete a cognitive-function test decreased after 10 weeks of supplementation with 80 or 160 mg of nitrate per day. Figure from Justice et al.⁴

In a similar study of 40 young people aged 18-27, other authors found that a single 450 ml dose of beetroot juice containing 5.5 mmol of nitrate, consumed 90 minutes before cognitive tests, improved cerebral blood flow and cognitive performance in one of the three tests. Specifically, participants started with a random number between 800 and 999 and repeatedly subtracted 3 in steps of 3 for two minutes (Figure 2).⁵

Figure 2. Acute nitrate supplementation appears to increase the number of correct responses on a cognitive-performance test. Figure from Weightman et al.⁵

Nitrates and Cognitive Performance in Sport

Although the studies above involved the general population, their promising results could also be highly relevant to sport. Cognitive demands may be relatively low in some sports, but in team, combat and racket sports, the cognitive component can be as decisive as the physical one. Making the right decision as quickly as possible despite high fatigue can determine the success of many actions, and the findings above suggest nitrates may play a role.

Supporting this hypothesis, a study of 16 team-sport players found that acute supplementation with 12.8 mmol of nitrate over 7 days improved not only performance during an intermittent sprint test, but also cognitive markers such as reaction time during the test, especially in the second half when fatigue had developed (Figure 3).³ It is important to mention, however, that not every study has found benefits. One study of 15 women competing in team sports found that a single nitrate dose of 12 mmol improved neither physical nor cognitive performance before or after an incremental intermittent test—the Yo-Yo test—⁶ although the use of a single dose may partly explain these results.

Figure 3. Nitrate supplementation (black bars) reduces reaction time compared with placebo (gray bars) during an intermittent sprint test, especially in the second half. Figure from Thompson et al.³

Conclusions

The vasodilatory power of nitrates may increase blood flow not only to muscles, but also to the brain. Although the evidence is not unanimous,⁷ several studies show that nitrate supplementation can improve cognitive performance in both the general population and athletes, for whom the ability to make correct decisions quickly can be decisive. More studies are needed to confirm the most effective supplementation method, although long-term supplementation—for example, 7 days—generally appears to provide greater benefits than a single acute dose.

Clifford (2018): No overall effect, but an association between intervention duration and improved cerebral blood flow. The review included 18 studies—13 on cognitive function and 8 on blood flow—with participants aged 21 to 73. Doses ranged from 3 to 13 mmol/day, with an average of 7. The studies used very different methods, ranging from reaction-time tests to memory exercises.

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References

1. Jones AM, Thompson C, Wylie LJ, Vanhatalo A. Dietary nitrate and physical performance. Annu Rev Nutr. 2018;38:303-328. doi:10.1146/annurev-nutr-082117-051622
2. Gao C, Gupta S, Adli T, et al. The effects of dietary nitrate supplementation on endurance exercise performance and cardiorespiratory measures in healthy adults: a systematic review and meta-analysis. J Int Soc Sports Nutr. 2021;18(1):1-11. doi:10.1186/s12970-021-00450-4
3. Thompson C, Wylie LJ, Fulford J, et al. Dietary nitrate improves sprint performance and cognitive function during prolonged intermittent exercise. Eur J Appl Physiol. 2015;115(9):1825-1834. doi:10.1007/s00421-015-3166-0
4. Justice JN, Johnson LC, DeVan AE, et al. Improved motor and cognitive performance with sodium nitrite supplementation is related to small metabolite signatures: A pilot trial in middle-aged and older adults. Aging (Albany NY). 2015;7(11):1004-1021. doi:10.18632/aging.100842
5. Wightman EL, Haskell-Ramsay CF, Thompson KG, et al. Dietary nitrate modulates cerebral blood flow parameters and cognitive performance in humans: A double-blind, placebo-controlled, crossover investigation. Physiol Behav. 2015;149:149-158. doi:10.1016/j.physbeh.2015.05.035
6. Tan R, Merrill C, Riley CF, et al. Acute inorganic nitrate ingestion does not impact oral microbial composition, cognitive function, or high ‑ intensity exercise performance in female team ‑ sport athletes. Eur J Appl Physiol. 2024;(3). doi:10.1007/s00421-024-05552-w
7. Clifford T, Babateen A, Shannon OM, et al. Effects of inorganic nitrate and nitrite consumption on cognitive function and cerebral blood flow: A systematic review and meta-analysis of randomized clinical trials. Crit Rev Food Sci Nutr. 2019;59(15):2400-2410. doi:10.1080/10408398.2018.1453779