If you scan through any sport magazine, it is likely you’ll find its pages stained purple with mentions of beetroot.
The root vegetable’s impact is whispered from different corners of the running world. Gossip leaked from athlete chaperones and drugs testers suggest which superstar athletes have purple urine as a result of beetroot shots.
Elsewhere, keen club runners bulk buy beetroot juice to help supplement their training in order to clip a further 15 to 20 seconds off their 5km personal bests.
However, according to British Athletics nutritionist Marc Fell, beetroot can benefit performances by being taken as a supplement as close as 90 minutes before a race.
“It is something that can be loaded to help boost efficiency, taken a week beforehand a race or even as a shot on the day,” Fell explains. “It is very difficult to achieve the levels or quantities of nitrates (a vital natural chemical which assists with oxygen exchange) needed through your diet as you’ve got to eat a hell of a lot of vegetables that are high in nitrates and different fruits.
“Athletes load on high nitrate concentrated products (i.e. beetroot juice and nitrate gels) to boost nitrate levels if they don’t have high levels of the natural chemical in their diet.
“Only five to seven days of loading are needed prior to competition to have an impact,” he adds. “There’s no real evidence that it needs longer. There’s also some evidence to suggest that 90 minutes before competition may have an effect as well.”
This is reflected in research from the University of Exeter which suggests nitric oxide will stay in the bloodstream for six hours after being consumed.
As a result of this, runners have a window in which their bodies will work more efficiently before exercise. By consuming a beetroot shot, runners boost their nitrate levels, meaning their bodies are able to work more efficiently.
The reason for beetroot’s benefits to exercise boils down to its high nitrate levels. Nitrates are a vital natural chemical which assists the body during high intensity exercise.
Nitrates, which are present in beetroot and some fruit such as rhubarb and green leafy vegetables such as cabbage and kale, are converted into nitric oxide conditions of low oxygen availability. Nitric oxide is known to play a number of important roles in vascular and metabolic control, so is considered an essential chemical for performance.
Any event which involves the body’s oxygen levels becoming depleted relies on nitric oxide to help it continue to work efficiently. The oxygen cost of exercise can therefore be reduced and athletes can work harder with less effort.
The first studies into nitrates’ impact on performance happened in Sweden in 2007 when nine cyclists were assigned a supplement composed of sodium nitrate, or a table salt placebo to take for three days in the build up to the scarily named ‘continuous incremental cycle ergometer test’ – commonly known as a seven-minute cycling time trial.
The results were dramatic. Nitrate supplementation significantly elevated resting plasma [nitrate] by 82% and significantly reduced blood pressure. Since then, the use of nitrates to boost performance has increased.
A study published in the Journal of Applied Physiology in 2013 found runners who took a beetroot juice shot before racing cut 1.5% off their 5km race times.
Nitrate levels are now widely considered when nutritionists produce plans for athletes and many sports teams are given rhubarb crumble the night before a competition because it is high in nitrates.
While studies show nitrates improve the efficiency in our muscles and blood, the benefits they bring vary for different runners. Elite athletes will not get the same benefits as other runners since their bodies are completely different.
Fell explained: “A lot of people thought it would be beneficial for the elite athletes too but it didn’t seem to have the same sort of effect because elite athletes have a very different physiological makeup.”
Since professional athletes’ bodies are already so efficient in oxygen exchange, the benefits they get from boosting their nitrate levels is smaller.
Other obscure factors also impact how effective nitrates are. According to Andrew Jones, professor of applied physiology at the University of Exeter, the process of nitrates being turned into nitric oxide involves bacteria found in the mouth. This means if you brush your teeth or use mouthwash after consuming the nitrates, the conversion process will stop.
While beetroot may provide an opportunity for runners to feel faster and stronger, Fell shared a useful insight into the use of beetroot among the British team.
“Some athletes brought beetroot shots abroad with them and they had exploded in their luggage, turning their kit purple!” said Fell.
So make sure if you do use the vibrantly coloured root vegetable, it’s kept separate from your race kit!
Jacob Phillips for World Athletics