Beetroot juice has become a staple among elite athletes, with claims it aided Eliud Kipchoge's marathon records and Jonas Vingegaard's Tour de France victories. But what does the evidence actually say for the rest of us?
Much of the research has been led by Professor Andy Jones, an exercise physiologist at the University of Exeter. His team's first study, published in 2009, found that recreational cyclists who drank beetroot juice daily for six days lasted around 90 seconds longer during a high-intensity cycling test compared with those who drank blackcurrant juice. The effect is attributed to nitrate in beetroot, which the body converts to nitric oxide, a molecule that widens blood vessels, reduces blood pressure and boosts oxygen delivery to muscles.
Subsequent studies have confirmed benefits across swimming, running and rowing. The International Olympic Committee lists nitrate from beetroot as one of only five dietary supplements with 'good to strong evidence' for performance enhancement, alongside caffeine, creatine, sodium bicarbonate and beta-alanine.
For non-athletes, a study by the University of Alabama at Birmingham found that adults with obesity took longer to reach exhaustion in a cycling test after consuming beetroot juice, suggesting it could make exercise feel easier and improve adherence. Meanwhile, a study published last month by King's College London found that chewing sugary gum after drinking beetroot juice further lowers blood pressure by enhancing bacterial activity in the mouth that converts nitrate to nitric oxide.
The late TV doctor Michael Mosley once described beetroot as 'vegetable Viagra', citing its nitric oxide effects on blood flow. However, experts warn that people with low blood pressure may experience dizziness, and those with diabetes should be mindful of its natural sugar content. The placebo effect may also explain some anecdotal claims of increased energy.