Beetroot juice / dietary nitrate

What it is

Beetroot is one of several vegetables, along with rocket, spinach and celery, that are naturally high in inorganic nitrate. Beetroot juice concentrates it into a small shot, and some supplements use beetroot powder or purified nitrate.

Endurance athletes, cyclists and runners use it most often, because the nitrate may make muscles use oxygen a little more efficiently during exercise. People also take it for blood pressure, though that is a separate question from sport.

It is a food-based product with a reasonable research base for a niche job. It is not a general energy booster, and results vary a lot between people.

How it works

Dietary nitrate is converted by bacteria in the mouth and then by the body into nitrite and nitric oxide. Nitric oxide relaxes blood vessels and can change how efficiently muscle cells use oxygen. Because the first step depends on oral bacteria, antibacterial mouthwash can blunt the effect.

What the evidence says

• Moderate Endurance exercise performance
  Several trials show small improvements in time to exhaustion or time-trial results, mostly in recreational rather than elite athletes.
• Moderate Lower resting blood pressure
  Short-term trials often show a modest drop in blood pressure, but it is not a replacement for prescribed treatment and long-term data are thinner.
• Moderate Oxygen cost of exercise
  Some studies show the body using slightly less oxygen at a given workload, which is the likely reason for any endurance gain.
• Limited High-intensity or strength performance
  Results are mixed and benefits, if any, look small.
• Weak Brain blood flow and cognition
  Early and small studies only; do not expect noticeable mental effects.

Evidence ratings are our plain-English summary of how much good human research exists, not a promise of results. How we rate evidence.

Dosage and timing

• Many studies use around 300 to 600 mg of nitrate taken 2 to 3 hours before exercise. Products vary widely, so work from the nitrate figure on the label, not the volume of juice.
• Some research uses daily dosing for several days, which may give a more consistent effect than a single shot.
• It can be taken with or without food. A very large amount of juice also brings a fair amount of sugar and calories.
• There is no official UK upper limit for supplemental nitrate that applies here; if you take blood pressure medication or have a health condition, check with a pharmacist or GP first.

Forms and what to look for

• Concentrated beetroot shots are the best-studied form and usually state nitrate content per bottle.
• Beetroot powder varies a lot in nitrate content and often needs several scoops for a study-level dose.
• Plain beetroot juice works but is bulky; you may need a large volume.
• Capsules rarely contain enough nitrate unless the label states a nitrate dose per serving.
• Look for a stated nitrate amount in mg, not just beetroot extract in mg.

What to expect, and when

• Blood nitrite rises within hours of a dose, which is why timing before exercise is the main variable.
• You will probably not feel anything. Any performance gain is small and shows up as slightly better times or less effort at a set pace.
• If it helps you at all, you would usually notice it within a week or two of using it consistently before sessions.

Side effects

• Beeturia: red or pink urine and stools, which is harmless in most people but can look alarming.
• Stomach upset or bloating, especially with large servings.
• Lightheadedness if blood pressure drops too far, particularly if you already have low blood pressure.
• Sugar load from juice versions.
• Nitrate-rich foods and supplements can be high in oxalate, which matters if you form kidney stones.

Interactions

• Blood pressure medication: the combined effect could lower pressure further; discuss with a GP or pharmacist.
• Nitrates and nitrate-like medicines for angina (for example GTN spray or isosorbide) and PDE5 inhibitors such as sildenafil: combined blood pressure lowering is a recognised concern, so ask first.
• Antibacterial mouthwash can reduce the conversion of nitrate to nitrite and weaken the effect.
• Antacids and acid-suppressing drugs may reduce nitrite conversion in the stomach.

Who should avoid it

• People with low blood pressure or who faint easily.
• Anyone on nitrate medicines for angina or on blood pressure treatment, unless a clinician agrees.
• People with a history of kidney stones, because beetroot is high in oxalate.
• Anyone with diabetes should factor in the sugar in juice versions.
• Pregnant or breastfeeding people should stick to food amounts and check with a midwife or GP.

Risks and safety

• Beetroot juice and nitrate are not on the WADA prohibited list, to the best of current knowledge; competitive athletes should still check current rules.
• Food-based nitrate is generally considered safe; very high nitrate intakes from other sources, such as contaminated water, are a different issue.
• Powders and capsules can contain much less nitrate than the label implies.

Buying well: quality and testing

• Choose products that state the nitrate dose per serving in mg.
• Third-party testing such as Informed Sport or NSF Certified for Sport matters for athletes who are tested.
• Be wary of vague proprietary blends that list beetroot without an amount of nitrate.
• Check sugar content on juices and shots.
• Fresh or minimally processed juice can vary batch to batch in nitrate content.

Bottom line

Beetroot nitrate is one of the few sport supplements with a plausible mechanism and a decent pile of positive trials, but the effect is small and works best for endurance rather than strength. If you enjoy beetroot and want to try it before a long ride or run, it is a low-risk experiment for most healthy people. If you take blood pressure or angina medication, ask a pharmacist first.