Who Should Not Take Beetroot Nitrates
Beetroot shots are one of the best-supported endurance supplements, yet the same blood-pressure-lowering effect that helps performance can cause problems for some people. Our editorial team explains who should avoid them and why.
How beetroot nitrates work
Beetroot juice and concentrated "beet shots" are among the few supplements with reasonably good evidence for endurance performance. Their active ingredient is inorganic nitrate, which is also abundant in leafy greens such as rocket, spinach and lettuce.
Once swallowed, nitrate is concentrated in saliva, where bacteria on the tongue convert it to nitrite. Nitrite is then turned into nitric oxide in the body, especially in low-oxygen conditions such as working muscle. Nitric oxide relaxes blood vessels and may make muscle energy use more efficient.
The International Olympic Committee consensus on dietary supplements lists nitrate among the few performance supplements with good supporting evidence, while noting that benefits are more consistent in recreational than in highly trained athletes.
Because nitrate lowers blood pressure, a property confirmed in a meta-analysis by Siervo and colleagues, it is not an entirely neutral substance. That effect underpins most of the cautions below.
Who should avoid or seek advice first
For most healthy adults, beetroot juice in normal amounts is a food and is very safe. Some groups, however, should not take concentrated nitrate products without professional advice.
| Group | Concern | Advice |
|---|---|---|
| People taking nitrate medicines (e.g. glyceryl trinitrate, isosorbide mononitrate) | Additive drop in blood pressure | Do not use concentrated nitrate supplements without doctor's approval |
| People taking PDE5 inhibitors (e.g. sildenafil, tadalafil) | Theoretical risk of excessive blood pressure fall | Speak to a pharmacist |
| People on blood pressure medicines | Combined lowering effect; dizziness | Monitor and discuss with GP |
| People with low blood pressure or fainting episodes | Symptoms may worsen | Avoid concentrated shots |
| People with a history of calcium oxalate kidney stones | Beetroot is high in oxalate | Seek advice; consider other nitrate sources |
| People with advanced kidney disease | Beetroot juice is rich in potassium | Follow renal dietitian advice |
| Infants | Risk of methaemoglobinaemia from high-nitrate foods | Not suitable |
Pregnant and breastfeeding women can eat beetroot and leafy vegetables as part of a normal diet, but there is little research on concentrated supplements, so they are best avoided during these periods.
Interactions you might not expect
Antiseptic mouthwash is a surprising factor. Studies, including work by Govoni and colleagues, showed that chlorhexidine mouthwash markedly reduces the conversion of nitrate to nitrite by oral bacteria. This is not dangerous, but it can cancel out the intended effect.
Proton pump inhibitors and other medicines that reduce stomach acid may also alter nitrite metabolism, although the practical significance is not fully understood.
Combining nitrate with other products that lower blood pressure or widen blood vessels, such as some "pump" pre-workouts, can increase the likelihood of light-headedness, particularly when standing up quickly after exercise.
Athletes subject to drug testing should note that nitrate itself is not prohibited, but multi-ingredient pre-workouts may contain banned stimulants; batch-tested products reduce that risk.
Harmless effects that worry people
Some effects of beetroot cause alarm but are not dangerous:
- Pink or red urine and stools (beeturia): caused by the pigment betanin; harmless, though anyone unsure whether it is blood should get checked.
- Stomach discomfort: concentrated shots can cause bloating or loose stools, especially before exercise.
- Earthy taste: a common reason people stop; concentrated shots reduce the volume needed.
Concerns about nitrate causing cancer relate mainly to nitrites and nitrosamines in processed meat, not to nitrate from vegetables. EFSA's assessment of nitrate in vegetables concluded that the benefits of vegetable consumption outweigh potential risks from nitrate exposure.
Nevertheless, there is no reason to take very large amounts. Studies on performance have generally used amounts in the region of 6–13 mmol of nitrate, taken a couple of hours before exercise, and more has not been shown to be better.
Making a safe decision
If you are healthy and not taking medicines that affect blood pressure, beetroot juice or a standardised nitrate shot is a reasonable supplement to try for endurance or high-intensity intermittent sport.
Test it in training rather than on race day, to check how your stomach tolerates it.
If you take any heart, blood pressure or erectile dysfunction medicine, ask your GP or pharmacist first. If you feel faint, dizzy or unusually tired after taking it, stop and seek advice.
Remember that a diet rich in green leafy vegetables provides nitrate along with fibre, vitamins and minerals, and this approach suits nearly everyone.
Editorial conclusions
Beetroot nitrates are among the better-supported performance supplements, but their blood-pressure-lowering effect means they are not suitable for everyone. People on nitrate medicines, PDE5 inhibitors or blood pressure treatment, those with low blood pressure, oxalate kidney stones or advanced kidney disease, and infants should avoid concentrated products or seek advice first.
Red urine and mild stomach upset are common but usually harmless.
Antiseptic mouthwash can blunt the effect, which is worth knowing if results disappoint.
Related reading: nitrates and endurance performance, citrulline versus arginine, and how to test a new supplement in training.
References
- Jones AM. Dietary nitrate supplementation and exercise performance. Sports Med. 2014;44(Suppl 1):S35–S45.
- Siervo M, Lara J, Ogbonmwan I, Mathers JC. Inorganic nitrate and beetroot juice supplementation reduces blood pressure in adults: a systematic review and meta-analysis. J Nutr. 2013;143(6):818–826.
- Lundberg JO, Weitzberg E, Gladwin MT. The nitrate–nitrite–nitric oxide pathway in physiology and therapeutics. Nat Rev Drug Discov. 2008;7(2):156–167.
- 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.
- Maughan RJ, Burke LM, Dvorak J, et al. IOC consensus statement: dietary supplements and the high-performance athlete. Br J Sports Med. 2018;52(7):439–455.
- European Food Safety Authority. Nitrate in vegetables: scientific opinion of the Panel on Contaminants in the Food Chain. EFSA J. 2008;689:1–79.
