Researchers at St Louis University in the US found that athletes, who ate baked beetroot before a race, were able to run five kilometres faster than those who had cranberries.
It follows other studies that have shown beetroot juice can increase stamina and make muscles more efficient. The root vegetable is known to contain high levels of chemicals, called nitrates, which have been shown to boost exercise performance.
In the new study, published in the Journal of the Academy of Nutrition and Dietetics, the researchers recruited a group of 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, or about 200 grams 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.
It was found that after eating the cranberry relish, the runners averaged a speed of 11.9 km per hour, but after having beetroot, their average speed went up to 12.3 km per hour, the Daily Telegraph reported.
Researchers said runners appear to be able to speed up in the last section of the run after eating beetroot.
"Consumption of nitrate-rich, whole beetroot improves running performance in healthy adults," said Margaret Murphy who led the study.
"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," Murphy said.
The study follows previous research on the benefits of beetroot. A study published in 2010 in the Journal of Applied Physiology had found that beetroot juice could have a powerful effect on stamina and endurance, as well as lower blood pressure. PTI SKP AKJ