EATING beetroot can boost athletic performance, research has suggested, by helping runners finish faster.
Scientists have discovered athletes who eat baked beetroot before a race put in a faster time.
The purple root vegetable contains high levels of chemicals called nitrates, which have been shown to boost exercise performance.
Researchers at St Louis University in America found athletes were able to run five kilometres faster after eating beetroot than after eating cranberries.
It follows other studies that have shown beetroot juice can increase stamina and make muscles more efficient.
The St Louis team recruited 11 fit and healthy men and women and asked them to run five kilometres on a treadmill, twice.
Before the first run, the volunteers consumed a portion of baked beetroot, of about 200 grams, or 7 ounces, of beetroot just over an hour before hitting the treadmill.
Before the second run, they ate an equivalent amount of cranberry relish, chosen because it has a similar calorific content to beetroot but without the same nitrate levels.
The results, published in the Journal of the Academy of Nutrition and Dietetics, showed that after eating the cranberry relish, the runners averaged a speed of 11.9 kilometres per hour, or 7.3mph.
But after consuming beetroot, their average speed went up to 12.3 kilometres per hour, around 7.6mph.
Researchers said runners appear to be able to speed up in the last section of the run after eating beetroot.
In a report on their findings, they said: "During the last 1.1 miles of the run, speed was five per cent faster in the beetroot trial."
Lead author Margaret Murphy wrote in the journal: "Consumption of nitrate-rich, whole beetroot improves running performance in healthy adults.
"Because whole vegetables have been shown to have health benefits, whereas nitrates from other sources may have detrimental health effects, it would be prudent for individuals seeking performance benefits to obtain nitrates from whole vegetables, such as beetroot."
Katie Lansley, a PhD student from the university’s Sport and Health Sciences department and lead author of the study, said: “As you get older, or if you have conditions which affect your cardiovascular system, the amount of oxygen you can take in to use during exercise drops considerably. This means that, for some people, even simple tasks like walking may not be manageable.
“What we’ve seen in this study is that beetroot juice can actually reduce the amount of oxygen you need to perform even low-intensity exercise. In principle, this effect could help people do things they wouldn’t otherwise be able to do.”
Beetroot juice seemed to widen blood vessels, reducing blood pressure and allowing more blood flow and affected muscle reducing the amount of oxygen needed during activity.