Beetroot supplies dietary nitrate, which the body turns into nitric oxide, and olive polyphenols may help that nitric oxide last longer and do more. The nitrate evidence is strong for endurance exercise and comes mainly from studies of concentrated beetroot juice. The case for pairing it with polyphenols rests on sound chemistry and smaller human studies. This article explains the pathway, the doses that were studied, and what a capsule can and cannot match.
How does dietary nitrate become nitric oxide?
Nitrate from vegetables is converted to nitrite by bacteria in the mouth, and nitrite is then converted to nitric oxide in the body.
This route is called the nitrate-nitrite-nitric oxide pathway (Lundberg et al., Nature Reviews Drug Discovery, 2008). It works alongside the body's own enzyme system, which makes nitric oxide from the amino acid arginine. The two routes differ in one useful way. The enzyme route needs oxygen. The nitrite route works best when oxygen is low and tissue is slightly acidic. That is the state of a hard-working muscle.
The steps run in order:
- You eat nitrate in beetroot, rocket, spinach or other leafy greens.
- It is absorbed, and about a quarter is taken back up by the salivary glands.
- Bacteria on the back of the tongue reduce nitrate to nitrite.
- Nitrite is swallowed, absorbed and converted to nitric oxide where it is needed.
The mouth is a real part of this system. In a small study, antibacterial mouthwash sharply reduced the rise in blood nitrite after a nitrate dose (Govoni et al., Nitric Oxide, 2008). If you use beetroot for training, avoid antiseptic mouthwash around the dose.
Nitric oxide relaxes blood vessels and helps regulate blood flow. Nitrite from a nitrate-rich drink also lowered blood pressure in healthy volunteers within hours (Webb et al., Hypertension, 2008). For athletes, though, the more interesting effect is inside the muscle.
What did the beetroot juice studies find?
Several days of nitrate lowered the oxygen cost of steady exercise and extended how long people could hold a hard effort.
The first signal came from Sweden. Three days of sodium nitrate reduced the oxygen people needed to cycle at a set submaximal workload (Larsen et al., Acta Physiologica, 2007). Exercise usually has a fixed oxygen price, so this was a surprising result.
Andrew Jones and colleagues at the University of Exeter then tested beetroot juice itself. In the best-known study, eight men drank half a litre of beetroot juice a day for six days (Bailey et al., Journal of Applied Physiology, 2009). Compared with a nitrate-depleted placebo juice, the oxygen cost of moderate cycling fell. Time to exhaustion during severe cycling rose. The placebo design matters. Both drinks tasted the same, so the effect came from the nitrate and not from the beetroot as a whole.
Many trials followed. A 2021 systematic review and meta-analysis pooled 73 studies (Gao et al., Journal of the International Society of Sports Nutrition, 2021). Nitrate improved endurance outcomes such as time to exhaustion, distance covered and power output. The average effects were small. They were also most consistent in endurance work, not in sprints or repeated power efforts.
What doses were used, and who responds?
Most positive studies used roughly 5 to 8 mmol of nitrate, taken about two to three hours before exercise or daily for several days.
One millimole of nitrate weighs about 62 mg. So 5 to 8 mmol is roughly 310 to 500 mg of nitrate. A dose-response study tested 4.2, 8.4 and 16.8 mmol in concentrated beetroot juice (Wylie et al., Journal of Applied Physiology, 2013). Blood nitrite peaked two to three hours after drinking. The 8.4 mmol dose improved exercise outcomes. Doubling it to 16.8 mmol added no further benefit.
Not everyone responds the same way. In a review of the field, Jones noted that effects tend to be clearer in recreationally active people than in highly trained endurance athletes (Jones, Sports Medicine, 2014). Well-trained athletes already have strong blood vessel function and high natural nitrate stores. Some still benefit. Fewer do, and by less.
Diet supplies nitrate too. A large salad of rocket or spinach, or a serving of cooked beetroot, can provide a meaningful share of a study dose. The amount varies widely with soil, season and storage.
Why might polyphenols protect nitric oxide?
Nitric oxide is destroyed quickly by free radicals, and polyphenols may help in two ways: by reducing that destruction and by helping convert nitrite to nitric oxide.
Nitric oxide lasts only seconds in the body. Its main enemy is superoxide, a free radical that increases during hard exercise. When the two meet, they combine into peroxynitrite. That reaction removes useful nitric oxide and creates a damaging oxidant at the same time. Antioxidant compounds that lower superoxide leave more nitric oxide free to act.
Polyphenols may also help at the start of the pathway. In laboratory and small human work, red wine polyphenols increased the conversion of nitrite to nitric oxide in stomach conditions (Gago et al., Free Radical Biology and Medicine, 2007). This is early research, but the chemistry is consistent.
Olive polyphenols have their own vascular evidence. In a small randomised crossover trial, young women with mildly raised blood pressure used a polyphenol-rich olive oil for two months (Moreno-Luna et al., American Journal of Hypertension, 2012). Compared with a polyphenol-free oil, blood pressure fell and endothelial function improved. Blood levels of nitric oxide breakdown products also rose. Hydroxytyrosol, a core olive phenol, also has an EU-authorised claim for protecting blood lipids from oxidative stress at 5 mg per day (Commission Regulation (EU) No 432/2012). That is an antioxidant claim, not a performance claim. It does show the compound works in the circulation.
No published trial has yet tested beetroot nitrate and olive polyphenols together for performance. The case for the pairing is mechanistic. Nitrate supplies the raw material. Polyphenols may protect the product. You can read more on our hydroxytyrosol page.
What can a capsule match, and what can it not?
A capsule cannot supply the 5 to 8 mmol of nitrate used in the juice studies, but it can add a steady daily polyphenol dose that juice does not.
This is the honest part. Research doses of nitrate come from concentrated juice shots or half a litre of juice. Two capsules hold well under a gram of powder in total. Even a concentrated beetroot extract cannot fit 300 to 500 mg of nitrate into that space alongside a polyphenol base. So the beetroot in a capsule is a contribution to your daily nitrate intake. It is not a replacement for a research-dose shot.
What a capsule does well is consistency. It delivers a measured, repeatable polyphenol dose every day, with no calories and nothing to refrigerate. Olive polyphenol content in oil varies by harvest and falls as oil ages. Juice nitrate varies by batch. A tested capsule removes one of those variables.
A practical approach for a race or key session:
- Keep your daily polyphenol dose steady through the training block.
- Eat nitrate-rich vegetables most days.
- If you want a research-level effect, add a concentrated beetroot shot two to three hours before the event.
- Skip antiseptic mouthwash on those days.
Test any change in training first, never on race day. Beetroot can turn urine pink, which is harmless.
How Pomoni fits
Phenolia Recovery combines Pomoni's three-source polyphenol base with Greek beetroot extract. The base is olive fruit extract, olive leaf extract and Greek Mountain Tea, verified by HPLC. Greek beetroot is a traditional source of dietary nitrates. The dose is two capsules a day. It is built for training and race blocks, to support normal recovery and healthy blood flow alongside a nitrate-rich diet. It layers with Phenolia Daily rather than replacing it. If you prefer food, Pomoni high-phenolic olive oil brings the same olive compounds to a salad of rocket and beetroot. For the wider training picture, see sports performance and olive oil for cyclists.
Frequently asked questions
How much nitrate did the beetroot studies use?
Most positive studies used about 5 to 8 mmol, which is roughly 310 to 500 mg of nitrate. It was taken two to three hours before exercise or daily for several days. Higher doses did not add further benefit in the main dose-response study.
Does Phenolia Recovery contain as much nitrate as a beetroot shot?
No. Two capsules cannot hold a research-scale nitrate dose. The beetroot extract adds to your daily nitrate intake. If you want the dose used in studies, add a concentrated beetroot juice shot before key sessions.
Why should I avoid mouthwash when taking beetroot?
Bacteria on the tongue convert nitrate to nitrite, the first step toward nitric oxide. Antibacterial mouthwash kills those bacteria. In a small study it sharply reduced the rise in blood nitrite after a nitrate dose.
Does nitrate help sprinters and lifters?
The evidence is weaker. Meta-analyses find the most consistent effects in endurance exercise, such as time to exhaustion and distance covered. Effects on sprints and repeated power efforts are smaller or absent.
These statements have not been evaluated by the Food and Drug Administration. Pomoni products are not intended to diagnose, treat, cure or prevent any disease.
Sources
- Lundberg JO, Weitzberg E, Gladwin MT. The nitrate-nitrite-nitric oxide pathway in physiology and therapeutics. Nature Reviews Drug Discovery. 2008;7(2):156-167. doi:10.1038/nrd2466
- Govoni M, Jansson EA, Weitzberg E, Lundberg JO. The increase in plasma nitrite after a dietary nitrate load is markedly attenuated by an antibacterial mouthwash. Nitric Oxide. 2008;19(4):333-337. doi:10.1016/j.niox.2008.08.003
- Webb AJ, Patel N, Loukogeorgakis S, et al. Acute blood pressure lowering, vasoprotective, and antiplatelet properties of dietary nitrate via bioconversion to nitrite. Hypertension. 2008;51(3):784-790. doi:10.1161/HYPERTENSIONAHA.107.103523
- Larsen FJ, Weitzberg E, Lundberg JO, Ekblom B. Effects of dietary nitrate on oxygen cost during exercise. Acta Physiologica. 2007;191(1):59-66. doi:10.1111/j.1748-1716.2007.01713.x
- 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. Journal of Applied Physiology. 2009;107(4):1144-1155. doi:10.1152/japplphysiol.00722.2009
- Gao C, Gupta S, Adli T, et al. The effects of dietary nitrate supplementation on endurance exercise performance and cardiorespiratory measures in healthy adults: a systematic review and meta-analysis. Journal of the International Society of Sports Nutrition. 2021;18(1):55. doi:10.1186/s12970-021-00450-4
- Wylie LJ, Kelly J, Bailey SJ, et al. Beetroot juice and exercise: pharmacodynamic and dose-response relationships. Journal of Applied Physiology. 2013;115(3):325-336. doi:10.1152/japplphysiol.00372.2013
- Jones AM. Dietary nitrate supplementation and exercise performance. Sports Medicine. 2014;44(Suppl 1):S35-S45. doi:10.1007/s40279-014-0149-y
- Gago B, Lundberg JO, Barbosa RM, Laranjinha J. Red wine-dependent reduction of nitrite to nitric oxide in the stomach. Free Radical Biology and Medicine. 2007;43(9):1233-1242. doi:10.1016/j.freeradbiomed.2007.06.007
- Moreno-Luna R, Munoz-Hernandez R, Miranda ML, et al. Olive oil polyphenols decrease blood pressure and improve endothelial function in young women with mild hypertension. American Journal of Hypertension. 2012;25(12):1299-1304. doi:10.1038/ajh.2012.128
- Commission Regulation (EU) No 432/2012 establishing a list of permitted health claims made on foods. Official Journal of the European Union. 2012. eur-lex.europa.eu
