Beet that: why athletes are turning to beetroot juice

If hearing that athletes are downing shots of beetroot juice to improve their performance makes you exclaim: “What sorcery is this?”, you’re not alone. But this isn’t just another passing fad - there’s some solid science showing that the nitrates found in beetroot juice can boost sports performance. From improving blood flow to enhancing muscle efficiency, beetroot juice has gained traction among endurance athletes and sprinters alike. In this podcast episode, I take a dive into what the research says about this vibrant supplement, its likely benefits, and what it might mean for your performance goals.

Links referred to in the podcast

• IOC consensus statement on dietary supplements and the high-performance athlete https://bjsm.bmj.com/content/52/7/439
• Review of beetroot juice and physical performance https://pubmed.ncbi.nlm.nih.gov/40573069
• Sports Dietitians Australia  www.sportsdietitians.com.au

Episode transcript
To access the full episode transcript, go to the following link and select the individual podcast episode and then click on the ‘Transcript’ tab https://thinkingnutrition.buzzsprout.com

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Transcript

If hearing that athletes are downing shots of beetroot juice to improve their performance makes you exclaim: “What sorcery is this?”, you’re not alone. But this isn’t just another passing fad - there’s some solid science showing that the nitrates found in beetroot juice can boost sports performance. From improving blood flow to enhancing muscle efficiency, beetroot juice has gained traction among endurance athletes and sprinters alike. Today, I’ll take a dive into what the research says about this vibrant supplement, its likely benefits, and what it might mean for your performance goals.

 Now if you don’t follow the world of sports supplement research closely, it may be a surprise for you to know that athletes are chugging down shots of beetroot juice before their training and competition. But this is not some faddish trend like Rubik’s cubes, finger spinners or activated almonds. There is now good science to show that beetroot juice, or more specifically a group of compounds called nitrates naturally found in beetroot and other vegetables, is able to show a benefit in improving sports performance.

Beetroot juice started its rise to fame over a decade ago when early studies began showing surprising improvements in time-trial performance, muscular endurance and perceived exertion. Suddenly, endurance athletes were looking beyond their usual pre-race caffeine shots and energy gels to this dark purple elixir. Since then, nitrate supplementation has become a staple in the research world, with hundreds of published papers exploring its effects across cycling, running, rowing and even team sports. You can also add to that list the growing research looking at its ability to lower high blood pressure, but that’s a story for another day.

So, what are these nitrates? Nitrates are inorganic compounds found in many vegetables such as spinach, celery, radishes, and lettuce, but beetroot is one of the highest sources. Nitrate contributes to the production of nitric oxide, which has an important role to play in immune function as well as regulating the tone of blood vessels which impacts blood pressure and blood platelet accumulation.

Nitric oxide is a potent vasodilator, meaning it improves blood flow and oxygen delivery to working muscles. Once consumed, nitrate is converted to nitrite, which circulates in the blood. When oxygen availability is low as can occur during exercise, nitrite can be converted to nitric oxide. Nitric oxide improves the muscles’ efficiency in using oxygen. Nitric oxide also augments exercise performance by enhancing the function of type II muscle fibres which are the fast-twitch muscles used in powerful bursts of movements like sprinting. And finally nitrate, through nitric oxide, can result in a reduction in the energy cost of muscle contraction and increased efficiency of mitochondrial respiration. That all means the muscles are finely tuned for explosive power when oxygen levels are limited.

So, whether it’s an elite cyclist wanting to shave precious seconds off a time trial or a recreational runner chasing a new personal best, nitrate-rich beetroot juice has moved from the novelty shelf to a performance-enhancing strategy grounded in evidence. Compelling enough that back in 2018 the IOC Consensus Statement on dietary supplements for use by high-performance athletes assessed beetroot juice as one of the few supplements to get the tick for having good evidence behind it. And I’ll link to this statement in the show notes. https://bjsm.bmj.com/content/52/7/439

From this IOC position statement, it stated that taking on extra nitrate in the form of beetroot juice can improve the exercise economy of athletes when working at a constant load which translates into a slightly longer time until exhaustion. So, for endurance athletes, this could convert into a small competitive advantage.

Based on the evidence at the time, the most studied exercise situations were cycling and running time trials from about 4 to 30 minutes in duration. At an elite level, clinical trials show a small, but competitively meaningful benefit in time trial performance. Recreational athletes appear to gain an even greater benefit from beetroot juice, which could be because of less prior adaptation of their cardiovascular system to exercise. Beetroot juice supplementation was also seen to improve performance in high-intensity, intermittent, team-sport exercise of 12 to 40 minutes in duration.

That was back in 2018, so how has the science evolved since then? Just recently there was an umbrella review published looking at the effect of beetroot juice on physical performance in professional athletes and healthy individuals as well. An umbrella review is simply a "review of reviews" that systematically synthesises evidence from multiple existing systematic reviews. For this one, it could include 15 systematic reviews. That’s a lot of reviews to review. Keep in mind though that there will be a lot of overlap between each of those reviews for the studies included, but the advantage of doing it this way is that there have been many different scientific eyeballs who have looked at the evidence. The controls used in the studies to compare against beetroot juice or nitrate supplements included a placebo, a low-nitrate beetroot juice, or no supplement. And I’ll link to the full review in the show notes. https://pubmed.ncbi.nlm.nih.gov/40573069

So, let’s just jump straight into what they found. Beetroot juice could significantly improve muscle strength, aerobic endurance as assessed by VO2 max and lactate tolerance as assessed by time to exhaustion. But, before you rush out to get yourself some of this magic elixir to propel yourself to greater sporting heights, the effect size, which is the magnitude of real-world benefit, was considered very small to negligible in all cases. Boo. There was an indication though that athletes gained more of a benefit for muscular strength while non-athletes saw more of a benefit for aerobic endurance, but again, the effect size was small.

And as expected with so many studies, there was a high degree of variability in the results which were a result of experimental design, participant characteristics, beetroot juice dosage and intervention duration.

As for dosages used, it ranged from 8 to 16 mmol of nitrates per day which is 285 mg to 1,017 mg of nitrate with an indication it was doses in the 500 mg and above range that were slightly more effective. And it seemed taking the nitrate-containing beetroot juice in the 2-to-3-hour window prior to exercise had a small edge compared to taking it chronically over several days before exercise.

To put those doses of nitrate in context, the highest natural dietary sources of nitrate are beetroot, celery, lettuce and spinach. They contain about 250 milligrams of nitrate per 100 grams, but levels can vary hence the popularity of the commercial beetroot shots. A dose of nitrate in the range of 400 mg can be provided by a single-serve of a commercial beetroot juice shot of about 70 mL taken about 2 to 3 hours before exercise. And even though beetroot juice can be made at home with a juicer, the concentrated shots are more popular owing to the much lower volume needed to drink compared to DIY juices. For the same amount of nitrate as you would get in a commercial 70 mL beetroot shot, you would have to swig down about half a litre of beetroot juice, which may not be too appetising in the hours before a race.

Happily, there is little concern about harmful effects from taking beetroot juice apart from some occasional minor gastrointestinal upsets. But as anyone who has tried beetroot juice will tell you, be prepared for a ‘colourful surprise’ on visits to the bathroom – what goes in purple comes out pink. But this pink colouration of the urine and stools is temporary and harmless.

As a side note, athletes using beetroot juice should avoid using mouthwash or gum as they reduce the bacteria available in the mouth that are essential for the conversion of nitrate to nitric oxide.

So, let’s wrap all this up. Like all sports supplements that have a credible research base behind them, the benefits of beetroot juice are quite small with a large degree of individual variation. Now it could be beetroot juice will do nothing for you as a person because of your own unique physiology, but if you actually believed they worked because of the research, then a small placebo effect is still valid. I’m certainly not saying that beetroot juice is a placebo – the evidence from many trials shows it works, albeit the effects are small, but those benefits represent the average of many people in the studies – and some showed greater benefits than others and others saw no benefit.

Consider this instead: if you put greater focus on including more of the naturally occurring high-nitrate foods in your diet on a regular basis, you’ll get the benefit of a constant higher baseline nitrate level in your body. If you want to trial beetroot shots then give them a go in training under close to competition conditions and if you feel they give you some extra pep, then by all means, certainly something to consider taking on race day.

My final word on this is to say that the use of any supplement or sports food for sports performance involves a balance between the potential benefits set against potential risks such as side-effects, anti-doping rule violations from contamination, and redirection of resources from real performance-enhancing factors. So, take this into account when considering taking any sports supplement. And seek out personalised advice from a sports dietitian. You can connect with an Accredited Sports Dietitian as well as access a great range of resources through the website of Sports Dietitians Australia at www.sportsdietitians.com.au

So that’s it for today’s show. You can find the show notes either in the app you’re listening to this podcast on, or else head over to my webpage at www.thinkingnutrition.com.au and click on the podcast section to find this episode to read the show notes.

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I’m Tim Crowe and you’ve been listening to Thinking Nutrition.