Beetroot juice seems like a completely safe product, but concentrated nitrate supplements have a real physiological effect - and therefore possible undesirable effects as well. The editorial team examined which side effects occur most often, who should be careful, and where the theoretical risk ends.
The overall safety picture
Beetroot nitrates are considered one of the safest sports supplements. In clinical studies where participants consumed concentrated beetroot juice for weeks, serious adverse events were practically not recorded. This is not surprising: we are talking about a component of ordinary vegetables that people have eaten for millennia.
At the same time, 'natural' does not mean 'without consequences.' Concentrated products contain as much nitrate as is hard to obtain from a plate of salad, and nitrates have a real physiological effect on blood vessels. Moreover, besides nitrates, beetroot contains pigments, oxalates, sugars, and potassium, which also have their own effects.
For an assessment, it is worth recalling the regulatory context as well. The acceptable daily intake of nitrate, established by JECFA experts and supported by EFSA, is 3.7 mg per kilogram of body weight. A typical dose of a beetroot shot for athletes exceeds this level. EFSA (2008) noted, however, that the benefit of consuming vegetables outweighs the potential risks of nitrates, but this conclusion concerned vegetables specifically, not concentrates.
Below, the editorial team examines side effects from the most common and safe to the rare but potentially serious.
Beeturia and digestive changes
The most common effect, which everyone should be warned about, is beeturia, that is, a pink or reddish coloring of the urine after consuming beetroot. The color is given by betalain pigments, which in some people are not completely broken down in the intestine. Stool can be colored in a similar way.
Beeturia is harmless, but it is easy to confuse with blood in the urine or stool. A person who does not know about this effect may be very frightened. At the same time, the review by Mitchell (2001) mentions that beeturia occurs more often in people with iron deficiency. So if the coloring appears for the first time and is very pronounced, it makes sense to check iron levels.
If, however, red coloring appears without consuming beetroot, is accompanied by pain, weakness, or does not go away for a long time - this is a reason to see a doctor immediately rather than blaming it all on the juice.
Gastrointestinal symptoms - bloating, rumbling, loose stools, sometimes heartburn - occur primarily when taking large volumes of juice, especially on an empty stomach or immediately before exercise. This is precisely why athletes often switch to concentrated shots of small volume and always test them during training rather than on competition day.
Blood pressure, the heart, and drug interactions
Nitrates lower blood pressure. In healthy people the effect is moderate: the study by Webb and colleagues (2008) showed a reduction in systolic pressure a few hours after consuming beetroot juice, and Kapil and colleagues (2015) recorded a sustained reduction in pressure in people with arterial hypertension when taken daily for several weeks.
For people with normal pressure this is usually unnoticeable. But in people with hypotension, a tendency to orthostatic reactions, or when combined with antihypertensive drugs, dizziness, weakness, and darkening of vision are possible on standing up abruptly.
Special caution is required when combining with phosphodiesterase-5 inhibitors (sildenafil, tadalafil) and medicinal organic nitrates. There is little direct data on dangerous interactions specifically with dietary nitrate, but the mechanism of action is shared - through nitric oxide - so theoretically the effects can be amplified.
Practical advice: if you are prone to low blood pressure or take vascular medications, measure your pressure at home in the first days of taking nitrates and avoid abrupt rises from a lying position. If dizziness appears, you should stop taking it and see a doctor.
| Effect | Who it concerns | What to do |
|---|---|---|
| Beeturia | Some people, more often with iron deficiency | Do not be alarmed; check iron if needed |
| Gastric discomfort | Large volumes of juice, intake on an empty stomach | Concentrated shots, test during training |
| Drop in blood pressure | Hypotension, taking blood pressure medications, PDE-5 | Consult a doctor before starting |
| Kidney stones | Tendency to oxalate stones | Limit beetroot, discuss with a urologist |
| Methemoglobinemia | Infants, poisoning by nitrite salts | Do not give concentrates to children, do not use salts |
Oxalates, kidneys, and potassium
Beetroot is one of the vegetables high in oxalates. Oxalates bind calcium and in susceptible people contribute to the formation of the most common type of kidney stones - calcium oxalate stones. For a person with no history of kidney stone disease this is unlikely to be a problem, but for those who have already had stones, urologists usually advise limiting products high in oxalates.
The oxalate content in concentrated shots and powders depends on the production technology and, as a rule, is not indicated on the label. So people prone to stones would do better to discuss alternative sources of nitrate with a doctor - for example, leafy greens with a lower oxalate content - or to give up the supplement.
Beetroot also contains potassium. For healthy kidneys this is not a problem, but for people with chronic kidney disease whose doctor limits potassium, concentrated juices may be unsuitable. In addition, with reduced kidney function the elimination of nitrate from the body slows down.
Finally, it is worth remembering sugar. Ordinary beetroot juice contains a noticeable amount of carbohydrates. For an endurance athlete this is not a minus, but people with carbohydrate metabolism disorders should take this factor into account.
Nitrosamines and methemoglobinemia: rare but serious
The most debatable question is the risk of cancer. The International Agency for Research on Cancer (IARC, 2010) classified ingested nitrates and nitrites 'under conditions that lead to endogenous nitrosation' as probably carcinogenic to humans (group 2A). This refers to the formation of nitrosamines in the stomach, especially in the presence of amines from meat.
At the same time, epidemiological data do not link vegetable nitrates with an increased risk of cancer, and vegetables contain vitamin C and polyphenols that inhibit nitrosation. Researchers' main attention is focused on nitrites in processed meat products. However, long-term intake of concentrated nitrate doses by athletes is a new situation, and there is no multi-year data on its safety.
Methemoglobinemia is a state in which hemoglobin loses the ability to carry oxygen. Nitrite oxidizes the iron of hemoglobin, and with an excess of nitrite, oxygen starvation of tissues develops. The most vulnerable are infants under six months (Greer et al., 2005). This is precisely why pediatricians do not advise giving them vegetables high in nitrates or water with a high nitrate concentration.
In adults, methemoglobinemia from vegetables or beetroot shots practically does not occur. The danger comes from chemical salts - primarily sodium nitrite. Numerous cases of fatal poisoning by sodium nitrite have been documented. So the editorial team categorically does not recommend experimenting with 'pure' salts instead of dietary sources.
Editorial conclusions
For a healthy adult, beetroot nitrates in the doses used in studies have a favorable safety profile. The most common effects are harmless beeturia and gastric discomfort from large volumes of juice.
Real caution is required for people with low blood pressure, those taking blood pressure medications or PDE-5 inhibitors, people prone to kidney stones, and those with kidney disease. Concentrates are unsuitable for infants, and nitrite salts are dangerous for everyone.
More about safe use is in our materials 'Who should not take beetroot nitrate,' 'How to take beetroot nitrate,' and 'Beetroot nitrate: product forms and which to choose.'
References
- 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.
- Kapil V, Khambata RS, Robertson A, et al. Dietary nitrate provides sustained blood pressure lowering in hypertensive patients: a randomized, phase 2, double-blind, placebo-controlled study. Hypertension. 2015;65(2):320–327.
- Mitchell SC. Food idiosyncrasies: beetroot and asparagus. Drug Metab Dispos. 2001;29(4 Pt 2):539–543.
- EFSA Panel on Contaminants in the Food Chain. Nitrate in vegetables: scientific opinion. EFSA Journal. 2008;689:1–79.
- IARC Working Group. Ingested nitrate and nitrite, and cyanobacterial peptide toxins. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. Vol. 94. Lyon: IARC; 2010.
- Greer FR, Shannon M; American Academy of Pediatrics Committee on Nutrition. Infant methemoglobinemia: the role of dietary nitrate in food and water. Pediatrics. 2005;116(3):784–786.
- Hord NG, Tang Y, Bryan NS. Food sources of nitrates and nitrites: the physiologic context for potential health benefits. Am J Clin Nutr. 2009;90(1):1–10.
- Clements WT, Lee SR, Bloomer RJ. Nitrate ingestion: a review of the health and physical performance effects. Nutrients. 2014;6(11):5224–5264.
Andriy Melnyk
A strength-sports coach and author of programs for beginner and intermediate levels. Writes about training planning.
