The hot new performance-enhancing drug is…beetroot juice!? (original paper)
Nitrates in food reduces the oxygen cost of some forms of exercise and improves high-intensity exercise tolerance. So the researchers gave half a litre of beetroot juice (which is rich in nitrate) or a nitrate depleted placebo to club-level competitive cyclists. The nitrate juice produced better cycling performance when compared to the placebo. On a 16.1 km race beet juice reduced the total time by 2.7% – not much, but presumably enough to matter in a competition.
In any case, this is fun for doping discussions. Should we ban athletes from quaffing beet juice?
The typical arguments against doping are that they are unhealthy, unfair and against the spirit of sports.
The health side seems to be pretty safe here: beet juice does not look like a major health danger. The amount used was 4-12 times greater than the typical daily dietary nitrate intake in the United States, but presumably not too hard to ingest. It looks like it is pretty safe, but it could perhaps turn out that the wrong diet or intestinal flora produces nitrosamines that in turn could give you cancer. But compared to other environmental factors (after all, these are people swooshing around very fast on roads!) that risk is likely pretty small, plus the added vegetable intake might counter it.
It is hard to argue that it is unfair to non-juice drinkers since they could presumably drink it too – it is not expensive or hard to come by. Some (like me) may not like the taste or the side effect of coloured urine, but this seems to be a weak anti-doping argument: presumably many athletes don’t like spandex either, yet trying to ban it from competitions where it helps performance because of their aesthetic judgements is a non-starter.
And drinking healthy fruit juice to get ready for competition seems to be so close to the spirit of sport that it is almost parody. Maybe drinking juice knowing the nitrate will turn into endurance-improving nitrite is the key difference – but clearly people preparing for competition already eat finely tuned meals or food they just think will help them. Would knowing the causal link between carbohydrates and energy metabolism make spaghetti inadmissible as a pre-marathon meal? It seems absurd. If the ‘spirit of sports’ depends on people doing sport in a ‘natural’ way without knowing about physiology, biomechanics and nutrition, then it has been lost a long time ago.
So my prediction is that during the current Tour de France 10-14% of the urine tests will be red.