Chinese nutritional theory has always held that beetroot has blood-nourishing properties. A British team has now found that beetroot juice can boost athletic stamina by increasing the nitrate concentration of the blood. In a double-blind, placebo-controlled crossover study, eight men drank 500ml of beetroot juice every day for seven days and completed a series of exercise tests on the last three days. They were able to cycle 16% longer without feeling fatigued and analysis showed that levels of nitrate in their plasma had effectively doubled. The authors suggest that the additional nitrate had the effect of slowing the rate of muscular energy metabolism, and suggest the finding will be of interest not only to athletes but also to elderly people and those with metabolic, respiratory or cardiovascular diseases. (Dietary nitrate supplementation reduces the 02 cost of low-intensity exercise and enhances tolerance to high-intensity exercise in humans. J Appl Physiol. 2009 Oct;107(4):1144-55).