Beetroot Human Clinical Research: What the Evidence Shows

Reader note: this article is educational and is not individual medical advice. Study details below were summarized from the published literature from memory of the sources cited; verify each against the original paper (titles, journals and years are given for PubMed lookup) before publishing.

Beetroot is one of the most studied foods in sports and cardiovascular nutrition, and also one of the most over-claimed. Headlines often say it "lowers blood pressure" or "boosts stamina" without saying in whom, at what dose, or for how long. This guide to beetroot human clinical research separates what controlled human studies actually measured from what remains hypothesis. You will see which outcomes have reasonably consistent support, which are mixed, and which are not yet established. If you want a clear, balanced reading of the evidence rather than a sales pitch, start here.

Executive Evidence Summary: Beetroot Human Clinical Research at a Glance

• Blood pressure: Short-term randomized trials, mostly with nitrate-rich beetroot juice, often show reductions of a few mmHg to around 10 mmHg in systolic pressure; meta-analyses support a modest average effect. Effects in long-term, free-living or diabetic populations are less consistent.
• Exercise performance: Acute and short-term juice studies frequently show a lower oxygen cost of submaximal exercise and small time-trial gains (about 1 to 3 percent) in recreational athletes. Highly trained athletes appear to benefit less.
• Cognition: Early human work suggests changes in cerebral blood flow; cognitive benefits are inconsistent and the evidence is thin.
• Heart failure, diabetes, kidney and other conditions: Small trials only. No evidence that beetroot treats or prevents disease.
• Hard outcomes (heart attack, stroke, death): no randomized evidence for beetroot itself.
• Not interchangeable: juice, whole root, powder and standardized nitrate products differ in nitrate content, other compounds and matrix. Results from one form should not be assumed for another.

Research Question: What Does Beetroot Do in Humans?

The question this page answers is narrow: In human participants, does consuming beetroot (in any defined form) change measured health or performance outcomes compared with a control, and how certain are we?

It matters because beetroot contains dietary inorganic nitrate (often roughly 250 to 1,500 mg per kg fresh weight depending on variety and growing conditions), along with betalains (the red pigments), polyphenols, fiber and potassium. Most clinical research assumes nitrate is the key active component. That is a reasonable but partly untested assumption, because many trials use nitrate-depleted juice as placebo, which tests nitrate specifically, whereas whole-food trials usually cannot.

Search and Inclusion Methodology for Beetroot Human Clinical Research

This summary was built the way an evidence overview should be, with the following transparent rules:

• Included: human randomized controlled trials (RCTs), crossover trials, systematic reviews and meta-analyses, and observational work on nitrate-rich vegetables where relevant.
• Excluded as primary evidence: animal and cell studies (mentioned only to interpret mechanisms), case reports, and marketing material.
• Sources to search: PubMed, Cochrane Library, Embase and Scopus, using terms such as beetroot, beet juice, dietary nitrate, blood pressure, exercise, cognition.
• Weighting: systematic reviews of RCTs sit above single RCTs, which sit above observational studies, with downgrading for small samples, short duration, risk of bias and indirectness.

Important limitation of this page: it is a narrative synthesis of key, widely cited studies, not a new registered systematic review. It does not claim to capture every trial. Readers needing exhaustive coverage should consult the cited meta-analyses.

Evidence by Health Outcome

Beetroot Juice Blood Pressure Evidence

Blood pressure is the best-supported outcome. The proposed mechanism is the nitrate-nitrite-nitric oxide pathway: dietary nitrate is absorbed, concentrated in saliva, reduced to nitrite by oral bacteria, and then converted to nitric oxide, which relaxes blood vessels (Lundberg et al., 2008). Supporting this, a human study found that an antibacterial mouthwash blunted nitrate-related blood pressure effects (Kapil et al., 2013). This mechanism is well characterized in physiology, but its translation into clinical benefit is the open question.

Acute effects. Webb et al. (2008) gave healthy adults 500 mL of beetroot juice and reported systolic reductions of around 10 mmHg a few hours later, with effects blocked when oral nitrite formation was suppressed. Sample size was small (14).

Multi-week effects in hypertension. Kapil et al. (2015) randomized 64 patients with hypertension to 250 mL of nitrate-rich juice or nitrate-depleted placebo daily for four weeks, finding reductions of roughly 8 mmHg systolic in clinic and ambulatory readings relative to placebo. This is among the most clinically relevant trials, though still only four weeks.

Null and mixed findings. Not every trial agrees. Coles and Clifton (2012) found no clear lowering of free-living blood pressure in healthy adults in a modest-sized trial. Bahra et al. (2012) found no change in flow-mediated dilatation despite nitrate intake. Gilchrist et al. (2013) found no improvement in blood pressure, endothelial function or insulin sensitivity in people with type 2 diabetes after two weeks.

Pooled evidence. Siervo et al. (2013) meta-analyzed trials and reported significant average reductions in systolic and smaller diastolic pressure. Ashor et al. (2017) examined medium-term trials (more than one week) and found smaller or less consistent effects than acute studies, a pattern consistent with tolerance or study heterogeneity. Zamani et al. (2021) systematically reviewed benefits and risks of beetroot juice and concluded effects on blood pressure were frequently favorable but heterogeneous.

Interpretation. Roughly speaking, the evidence supports a modest, short-term lowering effect of nitrate-rich juice, larger in people with raised blood pressure, but it is uncertain whether it is sustained over months or years.

Cardiovascular Health and Vascular Function

Beyond blood pressure, trials have examined arterial stiffness, endothelial function and platelet behavior. Results are inconsistent. Webb et al. (2008) reported reduced platelet aggregation and better endothelial protection after ischemia in healthy people, but Bahra et al. (2012) and Gilchrist et al. (2013) found no improvement in some vascular markers.

In heart failure with preserved ejection fraction, Eggebeen et al. (2016) found that one week of daily beetroot juice in a small group (about 20 patients) improved submaximal endurance and lowered blood pressure. It is hypothesis-generating rather than proof of better outcomes.

Observational data. Cohort studies link higher intakes of nitrate-rich vegetables with favorable cardiovascular risk markers and, in some cohorts, lower event rates. These are subject to confounding because vegetable eaters often differ in many other ways, and beetroot is rarely isolated as the exposure. No randomized trial shows that beetroot reduces heart attacks, strokes or cardiovascular death.

Nitrate Exercise Performance and Physical Endurance

This is the most active research area. Larsen et al. (2007) first showed lower oxygen cost of exercise with nitrate. Bailey et al. (2009) found that six days of beetroot juice lowered the oxygen cost of moderate exercise and extended time to exhaustion at high intensity in a small group of healthy men. Lansley et al. (2011) reported 2.8 and 2.7 percent faster 4 km and 16.1 km cycling time trials in club-level cyclists after acute juice.

Dose-response. Wylie et al. (2013) found that higher nitrate doses produced greater plasma nitrite and exercise benefits, with an apparent plateau; roughly 6 to 8 mmol of nitrate (around 400 to 500 mg) is a commonly used research dose. Timing, typically 2 to 3 hours before exercise, reflects peak plasma nitrite.

Whole food. Murphy et al. (2012) found that about 200 g of baked whole beetroot improved a 5 km running time by about 41 seconds in 11 participants, suggesting form matters less than nitrate delivered, though this is one small trial.

Null findings. Cermak et al. (2012) found no improvement in 10 km cycling time trial performance after a single dose of juice in trained cyclists. Elite and highly trained athletes frequently respond less, possibly because of higher baseline nitric oxide availability and greater muscle efficiency.

Pooled evidence. McMahon et al. (2017) pooled healthy-adult studies and found small to moderate benefits for time to exhaustion and some time-trial performance, with smaller effects in trained athletes. Jones (2014) and Jones et al. (2018) review the area in detail. The International Olympic Committee consensus (Maughan et al., 2018) lists nitrate as a supplement with supportive evidence for certain events, noting individual variability.

Practical caution. The effect sizes (a few percent) can matter in competition but are well within the day-to-day variability seen in many athletes. Gains are dependent on dose, training status and oral microbiome.

Cognitive Outcomes

The idea is that nitric oxide improves cerebral blood flow. Presley et al. (2011) found higher frontal lobe perfusion in older adults after a high-nitrate diet including beetroot juice, using brain imaging. Kelly et al. (2013) tested short-term nitrate in older adults and reported improvements in blood pressure and muscle measures, but not clear cognitive gains. Wightman et al. (2015) found that a higher dose of beetroot juice changed cerebral blood flow and improved performance on a serial subtraction task in healthy adults, but not across all tests.

The overall picture: changes in brain blood flow are plausible; clinically meaningful improvements in memory, dementia risk or daily functioning are not established. Samples are small, tasks are heterogeneous and many results are on secondary endpoints.

Other Outcomes

• Type 2 diabetes: null results in short trials (Gilchrist et al., 2013).
• Kidney, liver, inflammatory and metabolic conditions: very limited or preliminary human data. No firm conclusions.
• Safety: Zamani et al. (2021) note common minor effects such as red urine or stool (beeturia) and some gastrointestinal discomfort. Beetroot is high in oxalate, which is relevant for people prone to kidney stones, and high-nitrate intake may interact with blood pressure or nitrate-containing medicines; people on such drugs should consult a clinician.

Human Studies Table

Values are approximate and drawn from the published reports; please verify against originals.

| Year (first author) | Design | Population (n) | Beetroot form and dose | Duration | Primary endpoint | Result | Key limitations | |---|---|---|---|---|---|---| | 2008 (Webb) | Crossover RCT | Healthy adults (14) | Juice, 500 mL | Acute | Blood pressure | Systolic about 10 mmHg lower for hours | Small, acute only | | 2009 (Bailey) | Crossover RCT | Healthy men (8) | Juice, 500 mL/day | 6 days | O2 cost, time to exhaustion | Lower O2 cost, longer time to exhaustion | Very small, young men | | 2011 (Lansley) | Crossover RCT | Club cyclists (9) | Juice, 500 mL | Acute | 4 km and 16.1 km time trial | About 2.7 to 2.8% faster | Small sample, lab setting | | 2012 (Cermak) | Crossover RCT | Trained cyclists (12) | Juice, single dose | Acute | 10 km time trial | No improvement | Small, trained athletes | | 2012 (Murphy) | Crossover RCT | Active adults (11) | Whole baked beetroot, about 200 g | Acute | 5 km run time | About 41 s faster | Small, not nitrate-controlled | | 2012 (Coles) | RCT | Free-living healthy adults | Juice, daily | Weeks | Ambulatory blood pressure | No clear effect | Modest size | | 2013 (Gilchrist) | Crossover RCT | Type 2 diabetes (27) | Juice, 250 mL/day | 2 weeks | BP, endothelial, insulin sensitivity | No improvement | Short, stable medication | | 2015 (Kapil) | Parallel RCT | Hypertension (64) | Juice, 250 mL/day | 4 weeks | Clinic and ambulatory BP | About 8 mmHg systolic lower | Short, single center | | 2015 (Wightman) | Crossover RCT | Healthy adults (about 40) | Juice, 450 mL | Acute | Cerebral blood flow, cognition | Blood flow changes; mixed cognitive results | Multiple endpoints | | 2016 (Eggebeen) | Crossover RCT | HFpEF patients (about 20) | Juice, daily | 1 week | Submaximal endurance | Improved endurance, BP | Very small | | 2013 (Siervo) | Meta-analysis | Multiple trials | Juice and nitrate | Varied | Blood pressure | Significant average reduction | Heterogeneity, small trials | | 2017 (McMahon) | Meta-analysis | Healthy adults | Juice | Varied | Exercise performance | Small to moderate benefit | Bias, trained athlete effects |

Study Design Quality

Most trials are small randomized crossover studies, which are efficient but vulnerable to carryover effects. A recurring strength is the nitrate-depleted beetroot juice placebo, which allows blinding and isolates nitrate. Weaknesses include imperfect blinding (the red color and taste), short follow-up, small samples, multiple secondary outcomes without correction, and few preregistered protocols. Whole-food and powder trials rarely have equivalent placebos.

Participant Characteristics

Participants are mostly young, healthy, recreationally active men, with fewer women, older adults and patients. Findings may not generalize across sex, age, ethnicity, baseline blood pressure, medication use or diet. Higher baseline blood pressure appears to predict larger reductions, and highly trained athletes appear to respond less.

Dose and Form Used: Juice, Whole Beetroot and Powder Are Not the Same

• Juice: The most studied, often concentrated shots delivering roughly 5 to 8 mmol nitrate (about 300 to 500 mg). Commercial juices vary widely in nitrate content.
• Whole beetroot: Delivers nitrate plus fiber; absorption kinetics differ. Fewer trials.
• Powder and chews: Nitrate content depends on processing and varies. Evidence is more limited.
• Nitrate-standardized products: Most reliable for dose, but they may be marketed as sports supplements and quality should be independently tested.
• Nitrate sources outside beetroot (leafy greens, sodium nitrate) are used in some studies; extrapolating between them is uncertain.

Do not assume that a capsule, powder or processed juice replicates the trials above unless its nitrate content is known.

Duration

Most exercise studies are acute or up to about a week. Blood pressure trials run from a single dose to a few weeks; a few reach several weeks to months. Almost no trials follow people for years, so long-term benefits and safety are unknown.

Primary Endpoints

Common endpoints are systolic and diastolic blood pressure, oxygen uptake, time to exhaustion, time-trial performance, flow-mediated dilatation, cerebral blood flow and cognitive task scores. These are mostly surrogate or performance endpoints, not clinical events.

Results

Positive results cluster around acute blood pressure reduction, reduced oxygen cost and modest performance gains. Null results appear in diabetes, trained athletes and some healthy free-living samples. Both groups are included above, and neither should be dismissed.

Clinical Significance versus Statistical Significance

A statistically significant 4 mmHg reduction in systolic blood pressure can be meaningful at population scale (population modeling suggests small sustained reductions matter), but for an individual it is small and may not be sustained. A 2 percent time-trial improvement may matter for competitive athletes but is rarely significant for recreational exercise. Cerebral blood flow changes are not equivalent to better cognition, and blood pressure change is not proof of fewer cardiovascular events. Surrogate endpoints cannot be treated as proof of improved long-term health.

Conflicts of Interest, Funding and Publication Bias

Funding is mixed. Many trials are funded by universities and public research councils; some involve supplement companies or receive free product from beetroot juice manufacturers, and some authors have commercial links. This is not by itself evidence of bias, but readers should check each paper's disclosures. Small positive trials are more likely to be published than null ones, and funnel-plot-type bias has been discussed in the exercise literature; the true average effect may therefore be somewhat smaller than published pooled estimates.

Consistency Across Trials

Consistency is moderate for acute blood pressure lowering and for reduced oxygen cost of exercise; weak for time-trial performance in trained athletes; poor for cognition and vascular function; and unknown for long-term outcomes. Differences in nitrate dose, oral microbiome, baseline health, diet, medications and mouthwash use plausibly explain some heterogeneity.

Meta-Analyses and Systematic Reviews

• Blood pressure: Siervo et al. (2013) and Ashor et al. (2017) support modest reductions, with smaller and more variable effects in longer trials.
• Exercise: McMahon et al. (2017) supports small to moderate benefits in healthy adults; Jones et al. (2018) and Maughan et al. (2018) give expert context.
• Safety and benefits: Zamani et al. (2021) provide a broad review.

The quality of meta-analyses is limited by the quality of included trials, which are mostly small and short.

Evidence Grading

This informal grading is inspired by GRADE principles (Guyatt et al., 2008); it is a judgment, not a formal GRADE assessment.

Outcome	Certainty	Reasoning
Short-term blood pressure (juice)	Moderate	Multiple RCTs and meta-analyses; heterogeneity, small samples
Longer-term blood pressure	Low	Few, short trials; inconsistent results
Exercise performance (recreational)	Low to moderate	Consistent small benefits; bias and imprecision
Exercise performance (elite athletes)	Low	Frequent null findings
Vascular function	Low	Mixed results, small studies
Cognition	Very low	Small trials, surrogate measures, inconsistent tasks
Heart failure, diabetes and other conditions	Very low	A few small studies
Cardiovascular events or death	Not assessed	No randomized evidence

Limitations

Limitations include small sample sizes, short durations, selective populations, variable products, nitrate content not always measured, difficulty blinding whole-food interventions, publication bias, and reliance on surrogate endpoints. This article is also not a systematic review and may omit relevant studies. Evidence is insufficient to support firm conclusions on cognition, long-term cardiovascular protection, or use in disease management.

Frequently Asked Questions

Does beetroot lower blood pressure? Nitrate-rich beetroot juice lowers blood pressure modestly in many short-term trials, particularly in people with elevated pressure, but results vary and long-term effects are unclear.

Does beetroot juice improve athletic performance? It may modestly improve efficiency and time-trial performance in recreational athletes; evidence is weaker for elite athletes.

Is whole beetroot as good as juice? Possibly if nitrate delivered is similar, but trials are few. Do not assume equivalence.

Does beetroot improve brain function? It can change cerebral blood flow in some studies; evidence for real cognitive benefit is limited.

Can beetroot treat disease? There is no evidence that it treats or cures disease. It is a food or supplement, not a medicine.

Are there risks? Beeturia, digestive upset and oxalate load are the common issues. Talk to a clinician if you take blood pressure drugs or nitrate medicines, have kidney stones, or are pregnant.

Bottom-Line Interpretation: What Beetroot Human Clinical Research Supports

What the evidence supports: Nitrate-rich beetroot juice produces, on average, a modest short-term reduction in blood pressure and a small improvement in exercise efficiency and some performance measures, especially in non-elite adults.

What remains uncertain: Long-term blood pressure effects, benefits in trained athletes, cognitive outcomes, effects of powders and whole root compared with juice, and any effect on heart attack, stroke or mortality.

What future studies should do: Run larger, preregistered, longer RCTs with nitrate-matched placebos; include women, older adults and patients; measure oral microbiome and diet; compare forms head to head; and report clinical events and safety.

Beetroot can be a reasonable part of a vegetable-rich diet. Treat it as a dietary component with some physiologic effects, not a therapy.

References

Please verify DOIs and details through PubMed using the titles below.

1. Ashor AW, Lara J, Siervo M. Medium-term effects of dietary nitrate supplementation on systolic and diastolic blood pressure in adults: a systematic review and meta-analysis. J Hypertens. 2017;35:1353-1359.
2. Bahra M, Kapil V, Pearl V, Ghosh S, Ahluwalia A. Inorganic nitrate ingestion improves vascular compliance but does not alter flow-mediated dilatation in healthy volunteers. Nitric Oxide. 2012;26:197-202.
3. Bailey SJ, Winyard P, Vanhatalo A, et al. Dietary nitrate supplementation reduces the O2 cost of low-intensity exercise and enhances tolerance to high-intensity exercise in humans. J Appl Physiol. 2009;107:1144-1155.
4. Cermak NM, Gibala MJ, van Loon LJC. Nitrate supplementation's improvement of 10-km time-trial performance in trained cyclists. Int J Sport Nutr Exerc Metab. 2012;22:29-36. (Verify exact title and finding on PubMed before publishing.)
5. Coles LT, Clifton PM. Effect of beetroot juice on lowering blood pressure in free-living, disease-free adults: a randomized, placebo-controlled trial. Nutr J. 2012;11:106.
6. Eggebeen J, Kim-Shapiro DB, Haykowsky M, et al. One week of daily dosing with beetroot juice improves submaximal endurance and blood pressure in older patients with heart failure and preserved ejection fraction. JACC Heart Fail. 2016;4:428-437.
7. Gilchrist M, Winyard PG, Aizawa K, et al. Effect of dietary nitrate on blood pressure, endothelial function, and insulin sensitivity in type 2 diabetes. Free Radic Biol Med. 2013;60:89-97.
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21. Siervo M, Lara J, Ogbonmwan I, Mathers JC. Inorganic nitrate and beetroot juice supplementation reduces blood pressure in adults: a systematic review and meta-analysis. J Nutr. 2013;143:818-826.
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23. 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.
24. Wylie LJ, Kelly J, Bailey SJ, et al. Beetroot juice and exercise: pharmacodynamic and dose-response relationships. J Appl Physiol. 2013;115:325-336.
25. Zamani H, de Joode MEJR, Hossein IJ, et al. The benefits and risks of beetroot juice consumption: a systematic review. Crit Rev Food Sci Nutr. 2021;61:788-804.