18th April 2016
Many sports supplements make bold claims about boosting performance but only a few are backed up by credible research. In the second article of this 5-part series on supplements, I look at the evidence for beetroot juice.
What is it?
Beetroot juice (and beetroot) is a rich source of nitrate. It’s worth knowing that nitrate is also found in other vegetables, such as spinach, rocket, cabbage, endive, leeks and broccoli. But to consume enough nitrate to enhance your performance (300 – 400mg), you would need to eat at least 200g beetroot, 150g spinach or 100g rocket. Concentrated beetroot juice is therefore a more practical form of consumption.
What does it do?
“Beetroot juice may help improve exercise efficiency — in other words, it can reduce the energy required to exercise at a specific power output. This should translate into improved performance,” explains Andy Jones, professor of applied physiology at the University of Exeter. “It can also help you sustain higher levels of power for longer.”
The nitrates in beetroot juice are converted in the body into nitric oxide (NO), which when raised prior to exercise appears to help dilate blood vessels, aiding the delivery of oxygen and nutrients to muscles during exercise.
What’s the evidence?
Researchers at the University of Exeter found that drinking 500ml beetroot juice a day for a week enabled volunteers to run 15 per cent longer before experiencing fatigue. A further study by the same researchers found that cyclists given 500ml beetroot juice 2.5 hours before a time trial improved their performance by 2.8 per cent in a 4km race and by 2.7 per cent in a 16.1km race. A review of 17 studies by UK and Australian researchers concluded that beetroot or nitrate supplementation significantly improved endurance, as measured by time to exhaustion. Although time to exhaustion isn’t a direct measure of performance, this level of improvement could translate into a one to two per cent reduction in race time.
Gym-goers also stand to benefit from beetroot juice. A 2016 study at Edge Hill University found that beetroot juice can also improve resistance training performance. Volunteers who consumed a 70ml shot of beetroot juice (400mg nitrate) prior to training were able to complete more reps to failure (3 sets of bench press exercises at 60% 1RM) compared with those taking a placebo.
Verdict (How much and when)
It may not be the most palatable performance booster but there’s a solid base of evidence to suggest that beetroot juice may help you perform better during exercise lasting between four and 30 minutes, thanks to its high content of nitrates. It’s important to note that the majority of studies showing a positive effect involved untrained or recreational athletes. Whether beetroot juice also benefits performance in elite athletes is unclear.
Avoid using antibacterial mouthwash, as this removes beneficial bacteria in the mouth that convert some of the nitrate to nitrite and thus reduces the benefits of beetroot juice. As for side effects, there’s a harmless, temporary, pink colouration of urine and stools.
The optimal dose is likely to be 600mg nitrate, equivalent to 2 x 70 ml concentrated beetroot ‘shots’, say University of Exeter researchers, although it has also proved to benefit performance in studies using 300 – 400mg (0.62 mg/kg body weight), equivalent to 500ml beetroot juice or a single 70ml shot. Both acute and chronic loads have an effect. Professor Jones suggests consuming one to two 70ml shots a day for three to five days before competition as well as two to three hours before the race starts (blood NO levels peak 2 – 3 hours after ingestion and approach baseline 12 hours later). Boost your overall dietary nitrate by including more green leafy veg – plus you’ll gain the benefits of other nutrients in these foods too.
If you enjoyed this article and want to find out more about sports supplements, then read the new edition of my book
Fully updated to reflect the latest research, Sports Supplements is packed with clear, reliable and unbiased advice that will help you maximise your athletic potential. Renowned sports nutritionist Anita Bean takes you through each supplement and explains what they are, how to use them and if they really work – as well as suggesting other alternatives.
Covering the most popular supplements on the market – from beetroot juice to creatine, caffeine to whey protein, this is the essential guide for anyone considering taking supplements.