Leafy green vegetables could rival beetroot for benefits

Beetroot has a reputation as being a source of the beneficial nitrate substances found to enhance performance and recovery in sport. Yet, the root vegetable is not the richest source of nitrate, and researchers now suggest that leafy green vegetables, such as spinach, kale and Swiss chard, can be just as effective at boosting an athlete’s competitive edge.

For the new study, scientists at the University of Leuven in Belgium recruited 27 moderately trained athletes, who were given nitrate supplements before taking part in a sprint interval training session on a bike three times a week.

Volunteers were asked to train in different laboratory conditions, including normal oxygen and in hypoxic (low-oxygen) environments, such as those found in high altitudes.

Reporting his results in the journal Frontiers in Physiology, lead author Professor Peter Hespel revealed how the athletes’ muscle fibre composition changed with the enhanced nitrate intake after just five weeks of training in low-oxygen conditions.

“This is probably the first study to demonstrate that a simple nutritional supplementation strategy, ie, oral nitrate intake, can impact on training-induced changes in muscle fibre composition,” wrote Professor Hespel.

Training in hypoxic conditions requires a high input of fast-oxidative muscle fibre to sustain power. Enhancing these muscle fibre types through a nitrate supplement could help to achieve this, suggested the team.

In future trials, they will look at “whether addition of nitrate-rich vegetables to the normal daily sports diet of athletes could facilitate training-induced muscle fibre type transitions”, Professor Hespel said.

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