Nitrates in Beets: How Your Body Makes Nitric Oxide

Beets are among the richest dietary sources of inorganic nitrate, a compound your body can convert into nitric oxide, a molecule that relaxes blood vessels and improves oxygen delivery to tissues. A single serving of beetroot juice can contain upward of 5,000 micrograms of nitrate per milliliter, which is enough to measurably raise nitrite levels in your saliva and blood within hours.¹ That conversion underpins a range of health effects, from lower blood pressure to changes in exercise efficiency, but the story is more layered than “eat beets, feel better.”

Why Beets Are Such Heavy Nitrate Accumulators

Not all vegetables stockpile nitrate equally. Beets are natural accumulators: the plant pulls nitrogen from the soil and stores it as nitrate, particularly in its leaf blades and petioles. Greenhouse experiments found that beet leaf blades contained roughly three times more nitrate than the roots, and that the amount of nitrogen fertilizer applied to the soil was the single biggest factor driving how much nitrate wound up in the plant.² Field studies of beets grown in upland soils confirmed the same pattern: nitrogen fertilizer rate was the dominant factor, with higher applications producing significantly higher nitrate in roots, blades, and petioles alike.³

This means that two beets from different farms can have very different nitrate content depending on how heavily the soil was fertilized. Light intensity and other growing conditions also play a role, but nitrogen supply is king. For anyone drinking beetroot juice specifically for its nitrate content, this variability is worth knowing: a “concentrated” beet product from one manufacturer might deliver a different nitrate dose than one from another, simply because the beets were grown differently.

How Your Body Converts Beet Nitrate Into Nitric Oxide

Eating a nitrate-rich beet does not directly produce nitric oxide. The conversion requires a biological relay that runs through your mouth, stomach, and bloodstream. When you swallow beet nitrate, it gets absorbed in the gut and enters the bloodstream. Your salivary glands then actively concentrate that nitrate from the blood and secrete it into your saliva. On the back of your tongue, specific bacteria reduce the nitrate to nitrite. You swallow the nitrite-rich saliva, and in the acidic environment of your stomach, nitrite gets converted further into nitric oxide and related compounds.⁴

This process, often called the enterosalivary cycle, is predominantly dependent on those tongue-dwelling bacteria. Without them, the first and most critical step stalls. That has practical consequences we’ll get to shortly. Once nitrite reaches the bloodstream, further conversion to nitric oxide can also happen in blood vessels and red blood cells, particularly under low-oxygen conditions. Enzymes on the membranes of both red blood cells and blood vessel walls accelerate this conversion when tissues are oxygen-starved, which is part of why nitrate supplementation seems especially relevant during intense physical effort.⁵

Blood Pressure Effects

The most consistently studied effect of beet nitrate is its ability to lower blood pressure. A systematic review and meta-analysis of trials in people with high blood pressure found that beetroot juice significantly lowered systolic blood pressure by about 5 mmHg compared to placebo.⁶ Five points may not sound dramatic, but in population terms, a sustained drop of that size is associated with meaningful reductions in cardiovascular events. The effect on diastolic blood pressure (the bottom number) was smaller and did not reach statistical significance in that same analysis.

Beyond the pressure readings themselves, a study in midlife and older adults with reduced kidney function found that nitrate-rich beetroot juice improved vascular endothelial function, measured by how well the brachial artery dilated in response to increased blood flow. The improvement was about 28% compared to baseline, while a placebo produced no change.⁷ This matters because stiff, poorly responsive arteries are a hallmark of cardiovascular aging, and improving their flexibility is one plausible mechanism behind the blood pressure drop.

Historically, nitrate was viewed almost exclusively as a food contaminant linked to stomach cancer risk and a rare blood disorder in infants. Regulatory agencies set strict limits on nitrate in water and certain vegetables. But over the past decade, the evidence for cardiovascular benefit has been strong enough that some researchers now argue nitrate should be reconsidered as a nutrient rather than simply a contaminant, with the acceptable daily intake potentially needing revision upward.⁸

Exercise Performance and Fitness Level

Beetroot juice became a sports supplement staple in the late 2000s after an influential trial showed that dietary nitrate reduced the oxygen cost of low-intensity exercise by about 19% and extended time to exhaustion during high-intensity effort.⁹ The idea was compelling: if your muscles need less oxygen for the same work, you can go harder or longer before hitting a wall. But the research since then has revealed an important caveat. The benefit depends a lot on how fit you already are.

In less-trained individuals, the evidence is fairly consistent. A study comparing runners with lower and higher aerobic fitness found that the less-fit group showed significantly reduced oxygen cost at moderate intensities after nitrate supplementation, while the highly fit group saw no difference at all.¹⁰ Similarly, well-trained cyclists given high-dose beetroot juice for multiple days showed no improvement in exercise efficiency or oxygen-uptake kinetics during cycling in either normal or low-oxygen conditions.¹¹

An umbrella review synthesizing multiple meta-analyses put some numbers on this split. Recreational exercisers and non-athletes tended to see modest but real improvements in aerobic endurance, while professional athletes showed benefits more in the domain of muscular strength. Both effects were small in absolute terms.¹² The likely explanation is that elite athletes already have highly optimized oxygen-delivery systems. Their blood vessels are already efficient at producing nitric oxide through other pathways, leaving less room for dietary nitrate to add anything.

Short Bursts and Sprint Performance

Where things get more interesting, even at higher fitness levels, is during very short, explosive efforts. A study of football players found that acute beetroot juice supplementation significantly increased both mean and peak power during a 30-second all-out sprint test, with the supplement group also reaching peak power faster.¹³ A meta-analysis of sprint-cycling studies confirmed that acute nitrate supplementation improved time to peak power during 30-second sprints, though the evidence for overall mean power during those sprints was less clear.¹⁴

One study that compared recreational, competitive, and elite sprint athletes found no difference in the magnitude of beetroot juice’s effect across those levels, suggesting that for very short anaerobic bursts, the fitness-level ceiling seen in endurance work may not apply in the same way.¹⁵ The mechanism here likely differs from the endurance story: during explosive efforts, nitric oxide may improve the speed of muscle contraction itself rather than just oxygen efficiency.

Effects on Brain Blood Flow and Cognition

The same nitric-oxide pathway that widens blood vessels in your arms and legs also operates in the brain. A double-blind crossover study found that a single dose of dietary nitrate modulated cerebral blood flow during cognitive tasks, with an initial increase in blood flow at the start of the task period.¹⁶ A perspective review on Alzheimer’s disease noted that human studies suggest nitrate-rich beetroot can improve cerebral blood flow and vascular responsiveness, and that higher intakes of plant-derived nitrate are associated with slower cognitive decline.¹⁷

This is still early-stage research. Showing that a food changes blood flow in the brain is not the same as proving it prevents dementia. But the direction is consistent with what we know about vascular contributions to cognitive decline in aging: brains that get better blood flow tend to age more gracefully. Whether beetroot juice at practical doses can move the needle over years is a question no one has answered yet.

How Processing and Storage Change the Nitrate You Actually Get

If you are eating beets for their nitrate content, the form matters. A comparison of beetroot juice, chips, powder, and cooked beetroot found significant differences in nitrate levels across preparations. Juice had the highest nitrate content of any form tested, while chips and powder retained more antioxidants and organic acids.¹⁸ Home-processed beets were also found to contain significantly more nitrate than commercially processed ones, likely because commercial canning and processing methods leach nitrate into the liquid, which is often discarded. Pickled beets and Harvard-style beets (made with a sugar-based sauce) had the lowest nitrate on a dry-weight basis, partly because added sugar diluted the concentration.¹⁹

Storage temperature is another variable people rarely think about. Self-made beetroot juice stored at room temperature lost all of its nitrate within three days, as bacteria in the juice converted it to nitrite and then broke it down further. Refrigerating the juice at 4°C slowed that degradation by about 78%, and freezing preserved even more.²⁰ If you are making your own beet juice, the practical takeaway is simple: drink it fresh or refrigerate it immediately. Leaving it on the counter for a day or two guts the very compound you made it for.

Mouthwash and the Oral Bacteria Problem

Because the conversion of nitrate to nitrite depends on bacteria living on your tongue, anything that kills those bacteria disrupts the entire pathway. Antibacterial mouthwash is the most common culprit. A study that tested increasing strengths of mouthwash after a dietary nitrate load found a stepwise reduction in both salivary and plasma nitrite as mouthwash strength increased.²¹ In other words, a strong antimicrobial rinse can essentially shut down the nitrate-to-nitric-oxide pipeline, potentially negating the cardiovascular benefits of the nitrate you just ate.

This is not a niche concern. The antibacterial mouthwash market in the United States alone exceeds a billion dollars a year, and many people use it daily without realizing it could be counteracting the effects of an otherwise healthy vegetable-rich diet. If you are deliberately eating beets or drinking beetroot juice for blood pressure benefits, using a chlorhexidine-based or similarly strong antibacterial mouthwash around that time is working against yourself. Gentler mouth rinses without antimicrobial agents, or simply skipping mouthwash around meals, preserve the pathway.

Sex Differences in Nitrate Metabolism

An underappreciated detail in the nitrate research is that women and men do not process beet nitrate identically. A study examining the oral step of the enterosalivary cycle found that females had higher baseline oral nitrate-reducing activity than males, and this difference persisted after nitrate supplementation. Women converted more of the ingested nitrate into nitrite in the mouth, resulting in higher circulating nitrite levels. Interestingly, this was not linked to differences in which bacterial species were present; the same types of bacteria were simply more active.²²

What this means for practical outcomes is still being worked out. It could help explain some of the variability in blood pressure and exercise studies, where responses to the same beetroot juice dose can differ widely between individuals. Hormonal influences on the oral microbiome are one hypothesis, but the research has not settled on a mechanism yet. For now, the main point is that a one-size-fits-all dose recommendation for beetroot juice may be oversimplified.

Safety Considerations

For healthy adults, the nitrate in beets is generally safe at the amounts found in food and standard supplement doses. The concern that has lingered for decades is about nitrosamines, potentially carcinogenic compounds that can form when nitrite reacts with certain nitrogen-containing compounds. Laboratory studies of beet juice found that nitrosamine formation did occur at low levels during bacterial processing of the juice, but adding ascorbic acid (vitamin C) at 500 mg per liter reliably prevented it, as long as the pH stayed above 6 and bacterial conversion was active.²³ Beets naturally contain vitamin C, and most beetroot juice products include it, so this particular risk is largely managed in practice.

The population that does face real risk from dietary nitrate is infants, particularly those under six months. Their stomach chemistry and immature enzyme systems make them vulnerable to methemoglobinemia, a condition where nitrite in the blood prevents hemoglobin from carrying oxygen properly. Reports of nitrate poisoning from home-prepared vegetable foods, including beets, have continued to surface over the years, though commercially prepared infant foods in the United States appear to carry little risk because of controlled processing.²⁴ The standard pediatric advice against giving very young infants home-cooked beet puree remains well-founded.

How Beets Compare to Other Nitrate-Rich Vegetables

Beets get the spotlight, but they are not actually the highest-nitrate vegetable you can eat. Arugula, for instance, has been measured at higher nitrate concentrations than beetroot juice in direct comparisons, with arugula juice coming in at over 6,300 micrograms per milliliter versus about 4,965 for beetroot juice.²⁵ Spinach, celery, and lettuce are also high-nitrate foods. Beets have dominated the supplement market largely because they are easy to juice in large volumes, their flavor blends well in concentrated shots, and the deep red color (from betalain pigments) makes for appealing branding. But from a pure nitrate-delivery standpoint, a big arugula salad or a spinach smoothie can deliver a comparable dose.

The practical advantage of beetroot juice, especially commercially standardized products, is dosing consistency. When researchers run clinical trials, they use products with a known, measured nitrate concentration. Eating a bowl of mixed vegetables gives you nitrate, but you cannot know exactly how much, because it depends on the soil, the season, the storage conditions, and how you cooked it. For someone managing blood pressure or optimizing athletic performance, that predictability can matter.

Kidney Function and Open Questions

One area where the research remains thin is how beet nitrate interacts with kidney health. A study in healthy young adults found that beetroot juice consumption did not alter renal blood flow or kidney vascular resistance during normal breathing or during mild carbon dioxide exposure, suggesting it does not meaningfully affect kidney perfusion in the short term for people with healthy kidneys.²⁶ That is reassuring as far as it goes, but people with chronic kidney disease are a different population. They often have impaired nitric oxide metabolism to begin with, and while the vascular-function study cited earlier showed promise in older adults with renal dysfunction, the long-term effects of regular high-dose nitrate supplementation on compromised kidneys have not been well studied.

People on blood-pressure medications should also be aware that the hypotensive effect of beetroot juice can stack with their prescriptions. A 5 mmHg drop from beet juice on top of medication-induced lowering could push blood pressure uncomfortably low in some individuals, causing dizziness or lightheadedness. This is not a reason to avoid beets entirely, but it is a reason to mention them to your doctor if you are taking antihypertensives and planning to start drinking concentrated beetroot juice daily.