Juice or concentrate (≈300–600 mg of nitrate) 2–3 h before training.
⏱ 4 min read
Beetroot is Beta vulgaris, a widely cultivated vegetable whose characteristic purple root concentrates exceptionally high amounts of inorganic nitrates along with betalains (betacyanin and betaxanthin, the characteristic pigments with antioxidant activity), folates, fiber, and other nutrients; its emergence in modern sports nutrition over the past decade is directly related to the discovery of the nitrate-nitrite-nitric oxide cascade, a pathway parallel to and independent of NOS (endogenous nitric oxide synthase) for the production of nitric oxide that is actively regulated by commensal bacteria of the oral cavity and by human tissue enzymes.
The mechanism is elegant and specific: dietary nitrates (NO₃⁻) ingested with beetroot or beetroot juice are reduced to nitrites (NO₂⁻) by specific oral bacteria that live on the back of the tongue; the nitrites pass into the stomach and later into the bloodstream, where under conditions of low oxygen availability (during intense exercise, in hypoxic tissue areas) they are converted into nitric oxide (NO), which produces vasodilation, improved tissue oxygenation, a reduced muscular energy cost of work and, secondarily, improved endurance performance and reduced blood pressure; this mechanism is independent of NO produced by endogenous NOS and is active precisely in the conditions where classic NOS does not work well.
The indication with the strongest clinical support is improved endurance performance: multiple trials and meta-analyses have documented significant improvements of 1-3 percent in time-trial performance in endurance disciplines (running, cycling, rowing) and reductions in the muscular oxygen cost at submaximal intensities with supplementation at 5-8 mmol of nitrate (corresponding to 300-700 milliliters of concentrated beetroot juice, or to commercial products with standardized doses) taken 2-3 hours before exertion.
The effects are particularly significant in recreational or intermediate-level athletes; in elite athletes with a high baseline level of training, the effects are quantitatively more modest but still clinically relevant for competitions where tenths of a percent matter; nitrates are on the list of supplements with solid scientific support recognized by the International Olympic Committee and the International Society of Sports Nutrition.
In mild arterial hypertension, several trials have documented significant reductions in systolic (4-10 mmHg) and diastolic (2-5 mmHg) blood pressure with regular consumption of beetroot juice or nitrate supplementation for 4-8 weeks, clinically relevant magnitudes especially as an adjunct to lifestyle modifications in people with borderline readings.
In people with documented endothelial dysfunction, several studies have shown acute and chronic improvements in endothelial function with dietary nitrate supplementation, an indication consistent with the NO-modulating mechanism and with moderate clinical support.
In older adults and in people with cardiovascular risk factors, several small studies have documented acute improvements in cerebral blood flow and modest improvements in cognitive function with consumption of nitrate-rich beetroot juice, an indication consistent with the systemic vasodilator effect.
The doses studied range from 5 to 13 millimoles of nitrate (310-810 milligrams of nitrate), taken 2-3 hours before exertion for acute performance or on a sustained daily basis for chronic effects on blood pressure; the commercial forms are concentrated beetroot juice (variable depending on the product), fresh juice (variable depending on the beet), tablets or capsules with standardized doses, or consumption of whole beetroot as a food (a modest serving of cooked beetroot provides significant amounts of nitrates); sustained regular consumption is necessary for chronic cardiovascular effects.
Generally very well tolerated as a food; the adverse effects described are rare and mild: beeturia (pink-red urine) is completely benign and is due to the excretion of unmetabolized betalains in a variable percentage of people; digestive discomfort (gas, loose stools) may appear at high doses; in people with calcium oxalate kidney stones, beetroot provides significant amounts of oxalate, and consumption should be moderated; the most important pharmacokinetic consideration is that the effect depends on the oral bacteria that reduce nitrate to nitrite: the use of antibacterial mouthwashes (chlorhexidine and others) can partially eliminate this flora and reduce the ergogenic efficacy of dietary nitrates, a specific and well-documented interaction that should be avoided; people taking PDE-5 inhibitors (sildenafil) should be cautious because the combination with pharmaceutical nitrates is contraindicated owing to the risk of severe hypotension (dietary nitrates at the usual doses do not appear to pose the same risk, but clinical prudence advises avoiding the combination); in pregnancy and breastfeeding, usual dietary consumption is safe; concentrated supplements are significantly more expensive than traditional beetroot juice or beetroot itself as a food, a practical consideration when choosing a product.
Information, not medical advice. Scientific evidence reflects the quality of the studies.