Like many vegetables, beetroot contains a lot of naturally occurring nitrate. Dietary nitrates have been heavily investigated because it is these chemicals that are converted into nitric oxide, a potent vasodilator. Nitric oxide improves blood flow and oxygen delivery to working muscles.
Studies have shown that exercising athletes who supplement with beetroot juice, may gain a small benefit in exercise endurance. The supplementation of beetroot juice improves the exercise economy of athletes who are working at a constant load (i.e running). This results into a slightly longer time until the athlete reaches exhaustion, which may provide a subtle competitive ‘edge’. An effective dose of nitrate is approximately 400mg which can be taken from a commercial product or from high nitrate foods such as beetroot, lettuce and spinach. These foods contain approximately 250mg of nitrate per 100g. Bottom line – there is some credible evidence to suggest that beetroot supplementation may confer an advantage to endurance athletes (Int. Journal of Sport Nutrition & Exercise Metabolism, Apr 2013).