Dietary Nitrate Improves Vascular Markers—Not Proven CVD Prevention

Dietary nitrate can improve measurable aspects of vascular function. It has not yet proved that it prevents heart attacks, strokes, or cardiovascular deaths. That distinction matters more than any beetroot-juice marketing copy.

Nitrate-rich foods—especially beetroot and leafy greens—feed a well-described pathway: bacteria in the mouth convert nitrate to nitrite, then the stomach helps generate nitric oxide. Nitric oxide relaxes blood vessels and affects endothelial function, the ability of the vessel lining to respond appropriately to changes in blood flow. Randomized trials and three meta-analyses point in the same direction on vascular biomarkers. The unanswered question is whether those biomarker changes produce fewer clinical events.

What nitrate does after you eat it

Dietary inorganic nitrate does not work like a stimulant or a conventional drug. After ingestion, oral bacteria reduce nitrate to nitrite. Gastric chemistry then helps convert nitrite into nitric-oxide-related signaling molecules, increasing nitric oxide bioavailability. This enterosalivary pathway helps explain why nitrate can affect blood pressure, vascular tone, and endothelial responses.

The pathway also has a practical weak point: it depends on the mouth and stomach. In a mechanistic randomized trial of overweight women, Sanches-Lopes et al. (2024) found that bariatric surgery blunted nitrate-mediated improvements in cardiovascular function by interfering with gastric S-nitrosothiol formation. That result does not directly test proton-pump inhibitors, but it makes gastric acid physiology a serious concern rather than a footnote. People after bariatric surgery, with achlorhydria, or taking acid-suppressing medication should not assume that a nitrate supplement will work as it does in a healthy volunteer.

The best-supported outcomes are endothelial function and arterial stiffness

Flow-mediated dilation, or FMD, measures how much an artery widens in response to increased blood flow. It is an accepted predictor of cardiovascular risk and prognosis, but it is still a surrogate endpoint. Pulse wave velocity, or PWV, measures arterial stiffness; lower values generally indicate less stiff arteries.

A 2022 systematic review and meta-regression by Bahrami et al. evaluated 43 studies qualitatively and pooled 27 randomized controlled trials. Beetroot-derived inorganic nitrate increased FMD by 0.62 percentage points (p=0.002) and reduced PWV by 0.27 m/s (p=0.04). The review found no statistically significant effect on the other cardiovascular parameters it tested. Those are real, statistically significant changes in two vascular biomarkers; they are not evidence that nitrate lowers every cardiovascular risk factor.

A later systematic review and meta-analysis by Celik et al. (2025) focused on FMD and used random-effects models across randomized trials. Its most useful finding was not a single pooled number but the difference between short and sustained protocols. Acute protocols produced an FMD improvement of about 1.93 percentage points, while chronic protocols produced about 0.90 percentage points. The authors standardized acute FMD assessment to the two- to three-hour period after ingestion, when absorption peaks, to reduce timing-related variation.

The chronic estimate is more relevant to someone drinking beetroot juice every day for cardiovascular health. Acute studies can show a larger response because they measure the vascular system close to the post-dose peak. Whether the smaller chronic effect reflects tolerance, adaptation in oral nitrate-reducing bacteria, changes in nitric oxide signaling, or ordinary small-study noise remains unknown.

A third review, Norouzzadeh et al. (2025), used GRADE methods and dose-response meta-analysis of randomized trials. It also reported improvements in blood pressure, PWV, FMD, and augmentation index. Its agreement with the two earlier analyses increases confidence that dietary nitrate affects vascular biomarkers, although the available summary does not establish a minimum effective dose or a dose at which benefit plateaus.

Why the pooled numbers need restraint

Celik et al. reported I²=98% for the FMD evidence. That is extreme heterogeneity: the trials differed substantially in duration, dose, nitrate source, participant health, and measurement timing. A pooled effect can describe the direction of evidence while remaining a poor prediction of what will happen in one person.

Source also remains unsettled. Beetroot juice contains compounds beyond nitrate, including betalains and polyphenols. Leafy vegetables bring a different food matrix, while nitrate salts isolate the inorganic nitrate itself. No head-to-head trials in this evidence base establish whether those co-factors change vascular outcomes. The often-discussed 600 mg/day threshold is not a settled target dose; Celik et al. noted that reaching it would take roughly five beetroot portions per day, which is more a feasibility warning than a prescription.

The 2022 Bahrami review searched through November 2020, so it misses several newer trials. Many of the underlying trials were small, and some were pilot studies. Those features can inflate apparent effects and make subgroup findings fragile.

Who has been studied—and who has not

Several smaller randomized crossover trials show that nitrate can alter vascular responses under specific conditions. In postmenopausal women, Delgado Spicuzza et al. (2024) found that acute dietary nitrate improved endothelial resistance to ischemia-reperfusion injury versus placebo in a double-blind crossover trial. Another double-blind, placebo-controlled crossover trial, Rowland et al. (2024), found that nitrate ingestion blunted the rise in blood pressure during cool-air exposure. These results show altered responses to vascular stress; neither trial tested future cardiovascular events.

A 12-week randomized trial in postmenopausal females, Dos Santos Pinheiro et al. (2025), examined carotid arterial stiffness, providing the longest vascular-endpoint follow-up described here. It helps move the field beyond one-off dosing, but it does not explain why chronic FMD responses appear smaller than acute ones.

Nitrate may also remain biologically active in disease states. Pedrinolla et al. (2025) reported improved vascular responsiveness after nitrate-rich beetroot juice in people with Alzheimer's disease. In peripheral arterial disease, a randomized crossover study of 18 patients compared nitrate-rich vegetables, beetroot juice, and nitrate-depleted beetroot juice; it assessed exercise tolerance, muscle oxygenation, blood pressure, arterial stiffness, and cardiovascular function 150 minutes after intake. van der Avoort et al. (2022) supports the pathway's relevance in impaired peripheral circulation, but its small size and acute design limit broader conclusions.

Generalizability cuts both ways. Menopause may reduce endogenous nitric oxide availability, potentially leaving more room for an external nitrate signal. In contrast, menstrual-cycle variation may alter nitrate response in premenopausal women; a double-blind study of 10 normally menstruating women tested beetroot juice or nitrate-depleted placebo across early and late follicular phases. Hogwood et al. (2023) found that this area needs more data, not a universal dose recommendation.

The obesity gap is worth taking seriously

The people at highest cardiovascular risk are not always the people most represented in nitrate trials. A single-dose, placebo-controlled trial in grade 1 obesity found that tadalafil, which amplifies nitric-oxide-linked cGMP signaling downstream of nitrate, improved haemodynamics and arterial stiffness but did not improve FMD. Larios-Cárdenas et al. (2022) did not test dietary nitrate, so it cannot refute nitrate supplementation. It does show that pushing the nitric oxide pathway does not automatically restore endothelial function in metabolic disease.

That concern fits the heavy heterogeneity and healthy-volunteer representation in the broader literature. We do not know whether the pooled FMD changes apply equally to people with obesity, diabetes, or metabolic syndrome.

Verdict: a reasonable food strategy, not proven cardiovascular prevention

For generally healthy people with intact gastric physiology, nitrate-rich foods and concentrated beetroot juice have consistent randomized-trial evidence for modest improvements in FMD and arterial stiffness. The best estimate for sustained endothelial benefit is closer to the roughly 0.90-percentage-point chronic FMD change than the 1.93-percentage-point acute response. The 0.62-percentage-point pooled FMD increase and 0.27 m/s PWV reduction in the broader 2022 review support the same basic conclusion.

Use nitrate-rich foods as part of a dietary pattern that already supports cardiovascular health. Do not treat them as a substitute for blood-pressure control, lipid treatment when indicated, exercise, smoking cessation, or prescribed care. No randomized trial in this evidence base has shown fewer myocardial infarctions, strokes, or cardiovascular deaths. Dietary nitrate has a credible vascular-biomarker case. It does not yet have an outcomes-trial case.