Here is an interview with one of the greatest physiologists in the United Kingdom - Professor Andrew Jones, now Associate Dean Research in the College of Life and Environmental Sciences at the University of Exeter.
An interview with Prof Jones...
The first time I met Andy was probably when we both served on a sport science panel for UK Athletics (some time ago). I knew Andy as a physiologist, who primarily studied VO2 kinetics (how rapidly your body can take up oxygen) and worked with elite athletes, including Paula Radcliffe. Andy tested Paula from a young age and of course several years later Paula went on to run a record for the marathon that still stands today. Nowadays Andy is known by many people for his work with beetroot juice. So I wanted to ask Andy a few questions. Most of these questions are beetroot related questions that I get asked sometimes by athletes and coaches and have great practical relevance.
Asker: Andy, how does one become a beetroot expert? Originally your career developed in physiology, not necessarily in vegetables. How did you become interested in beetroot?
Andy: You’re right that in my career so far I’ve been mainly interested in muscle energetics, fatigue and respiratory physiology rather than sports nutrition. However, my interest in dietary nitrate (and there is a lot of this substance in beetroot juice) arose because of evidence that it can change muscle efficiency. Any intervention that can reduce the oxygen cost of exercise – in other words, make people more economical during exercise – has the potential to improve their performance. Since our original discovery that beetroot juice has several important physiological effects, we’ve been interested in finding out more – both about the mechanisms and also the practical applications.
Any intervention that can reduce the oxygen cost of exercise has the potential to improve performance
Asker: How strong would you say is the evidence that beetroot juice has performance and other physiological effects?
Andy: Pretty strong, I think. I don’t think there’s much doubt that nitrate has physiological effects. The evidence for dietary nitrate reducing resting blood pressure, and therefore potentially impacting positively on cardiovascular health, is really robust. The key now is to find out in which populations and sporting events it may be most effective in improving performance.
Asker: How would you advise people to use it? What dose, what form? How much, when? How many days etc.
Andrew: We did a ‘dose-response’ study recently which showed that beetroot juice containing 8 mmol nitrate (this is contained in two concentrated 70 ml ‘beetroot shots’ for example) was effective in improving efficiency and performance and that these effects were no greater when double the amount was consumed. Other studies have shown that 5-6 mmol can be effective in some people. The effects are likely to be greater if beetroot juice is consumed for several days prior to a competition but there are acute effects too and I would recommend taking nitrate 2-3 hours prior to competition.
The effects are likely to be greater if beetroot juice is consumed for several days prior to a competition
Asker: Does it have to be beetroot? Or are there other foods that could have the same effects?
Andy: Various green leafy vegetables, such as spinach and lettuce, also contain a lot of nitrate, and consuming more of these should be encouraged. The problem is that it’s not always certain exactly how much nitrate they contain (this can vary according to where and when the vegetables were grown, for example). Therefore, for sport, it’s usually more convenient to consume a beetroot juice or other high-nitrate product.
Asker: Many endurance athletes use beetroot juice but a lot of the evidence is in short duration higher intensity exercise. What are the effects of beetroot juice in prolonged endurance activities?
Andy: This hasn’t been addressed much. We once looked at the effects of beetroot juice on a 50 mile cycle time trial. There was no significant effect overall but power tended to be better later in the ride and those cyclists who ‘responded’ better (by increasing their plasma [nitrite] most), performed better.
Asker: Could you take beetroot juice late in exercise? For example if a cyclist takes it after 3 hours to get ready for a tough climb later in the race? Does this work? If not why not?
Andy: This is a really important question and one we intend to tackle. During exercise, plasma [nitrite] declines and so ‘topping up’ by consuming nitrate during exercise might be beneficial. There is a complication though because it can take some time (1-2 hours) for dietary nitrate to be processed in the body.
Asker: The active ingredient is nitrate. Nitrate also has a bad name and nitrate content in drinking water for example is highly regulated. Is nitrate safe in your opinion?
Andy: The view on nitrate is changing rapidly with a consensus emerging that it is actually good for our health. The World Health Organisation Expert Committee on Food Additives stated: ‘‘Overall, the epidemiological studies showed no consistently increased risk for cancer with increasing consumption of nitrate. These data, combined with the results of the epidemiological studies considered by the Committee, do not provide evidence that nitrate is carcinogenic to humans.” However, it is important that nitrate is not confused with nitrite – the former is considered to be safe (and is slowly converted in our bodies to nitrite), but direct ingestion of the latter can be toxic.
The view on nitrate is changing rapidly with a consensus emerging that it is actually good for our health.
Asker: What can we expect to find out in the future? What are the main questions we still need to address?
Andy: Recent papers suggest that fast-twitch muscle fibres might be especially affected by nitrate. This indicates that high-intensity intermittent exercise performance, such as occurs in team sports, might be positively impacted by nitrate. We are also seeing evidence that nitrate can influence brain blood flow and perhaps cognitive function so there may be new applications here too.
High-intensity intermittent exercise performance might be positively impacted by nitrate
Asker: Thank you very much Andy for sharing your knowledge and experience. Please keep up the great work and keep us informed of any new developments.
A blog about Professor Jones' recent paper showing effects of beetroot juice on intermittent exercise and cognitive function can be found here, with a link to the original paper.