Beetroot: benefits, nitrates and sports performance

What nutrients does beetroot contain?

Beetroot is mostly water, with almost nine out of every ten grams being water. So although it tastes sweet, it provides little energy. Here are the values per 100 g of edible portion according to the Spanish food composition tables [1]:

• Water, about 89 g.
• Energy, about 37 kcal.
• Carbohydrates, about 6.4 g, almost all of them sugars.
• Fibre, about 3 g.
• Protein, around 1.3 g.
• Potassium, about 300 mg.
• Folate, about 90 µg. This B vitamin is involved in the formation of blood cells.
• Vitamin C, about 10 mg.

A side or salad portion of 100 to 150 g can easily be part of lunch or dinner on any day.

Its red colour comes from betalains, not anthocyanins, as is sometimes said. The food industry uses these pigments as a colouring agent, code E162. The leaves are edible and can be cooked in the same way as Swiss chard.

What do beetroot nitrates do in the body?

Beetroot is among the foods highest in nitrate, along with green leafy vegetables such as rocket, spinach and Swiss chard [2]. Nitrate does not act on its own. Bacteria in the mouth convert it into nitrite, which the body then converts into nitric oxide [2]. This molecule helps widen blood vessels and allows muscles to use less oxygen for the same effort [2].

This step in the mouth has a practical consequence. Antiseptic mouthwashes slow the conversion and, with it, much of the effect [2]. If your dentist has recommended one, follow their instructions.

Does beetroot improve sports performance?

A little, and not for everyone. An analysis of 80 studies found a small effect compared with a placebo, seen mainly in young, healthy men who exercise recreationally [3]. No improvement was seen in highly trained endurance athletes [3]. Studies conducted only with women also found no clear effect, although there are too few to draw conclusions [3].

Another review of dietary nitrate points in the same direction. The benefit is smaller and less consistent the more highly trained a person is [2]. The International Olympic Committee lists nitrate among the few supplements with good evidence of benefit [4]. If you are considering taking it as a supplement, your doctor or dietitian-nutritionist should prescribe it. Sports supplements should not be used by minors. The Committee also cautions that responses vary considerably from person to person and that any change should be tried in training first [4].

In studies, it is taken about two or three hours before exercise, when nitrite levels in the blood rise the most [2]. As a food, the simplest option is a glass of homemade juice or a serving of beetroot with the meal beforehand. The amount depends on your sport, the duration of the event and how well you tolerate it, and should be adjusted individually.

Does beetroot lower blood pressure?

It may lower it slightly in people with high blood pressure, but it does not replace medication. An analysis of seven trials found that beetroot juice reduced systolic blood pressure, the upper number, by about 5 mmHg [5]. Diastolic blood pressure, the lower number, barely changed, and the studies lasted no more than two months [5]. Longer trials are needed to find out whether the effect lasts [5].

If you take medication for blood pressure, do not change it or stop taking it because you eat beetroot, and discuss this with your doctor. What does make sense is including beetroot as part of a diet rich in vegetables.

If you have kidney stones or need to monitor potassium

For most people, beetroot does not cause problems. There are three situations in which it is worth paying closer attention.

• Calcium oxalate kidney stones. Beetroot and its leaves contain oxalate. The European urology guidelines recommend that people who form these stones limit foods high in oxalate [6]. They also advise drinking more fluid and keeping calcium in meals [6]. You do not need to eliminate beetroot; ask your urologist or dietitian-nutritionist what amount is right for you.
• Kidney disease requiring potassium monitoring. If your doctor has asked you to monitor potassium, beetroot and its juice count towards your intake [1]. Follow the guidance you were given.
• Sensitive stomach. A large glass of juice all at once may upset your stomach, especially just before running. That is why it is a good idea to try it first during an easy training session.

How to serve beetroot

The most convenient option is cooked, packaged beetroot, ready to use and easy to keep in the fridge. Check the label and choose one with no added sugar.

• In a salad, diced with rocket, orange segments, walnuts and fresh cheese.
• Raw and grated, with carrot and apple, dressed with extra virgin olive oil and lemon.
• Roasted, cut into wedges and roasted with the skin on, alongside sweet potato or onion, as a side for fish, chicken or pulses.
• As a spread, blended into hummus with cooked chickpeas, beetroot, tahini and lemon.
• In a chilled soup, in summer, with tomato, cucumber or plain yoghurt.
• As homemade juice, on its own or with carrot. It is better to eat fruit whole. Juice contains less of the fibre found in whole vegetables.

All these ideas fit into a Mediterranean diet, with vegetables making up half your plate at lunch and dinner.

What mistakes do we see in consultations about beetroot?

These are the three ideas about beetroot that we most often correct in consultations.

“The juice will make me faster.” No vegetable can make up for eating too little for your training, spreading protein poorly throughout the day or not resting well. Our guide to sports nutrition for training, competing and recovery covers the full approach.

“I drink the juice instead of drinking during a long training session.” Beetroot juice does not replace the fluids you drink to stay hydrated. Our guide to sports drinks explains how much to drink and when a drink with salts may make sense.

“My urine turned red and I got scared.” Pink or reddish urine or stools after eating beetroot have a name: beeturia. It happens to some people because the pigment is not fully broken down, and it is harmless. Very dark, cola-coloured urine with intense muscle pain after an unusual training session is different. That requires urgent care today [7].