Beetroot is unsurpassed as the ‘superfood’ of choice for runners. But is the humble root really a guaranteed recipe for success, asks Peta Bee
Barely a month seems to pass without another study emerging to confirm the benefits of beetroot.
Latest findings from the world of exercise science suggest the vegetable itself or shots of its juice can improve everything from sprint speed to endurance capability and strength to recovery.
With entire university research teams now dedicated to researching its effects on the body, its reputation as a performance aid is seemingly based on more than speculation. Here, we dig up the evidence.
WHAT MAKES IT SO GOOD?
Beetroot’s scientific credibility hangs on it being a rich source of nitrates, compounds found in the vegetable that are converted by the body to nitrite and then nitric oxide, a molecule that not only relaxes and widens blood vessels, but influences how efficiently our body’s cells use oxygen.
A growing body of evidence suggests nitrates play a role in improving blood flow, maintaining immune function and cardiovascular health and potentially enhancing exercise performance. Nitrates and mitochondria, the energy-producing powerhouses of our cells, are able to utilise oxygen more sparingly, thereby conserving energy. Numerous studies have suggested that a good dietary intake of nitrates lowers the oxygen cost of exercise to such an extent that stamina rises by up to 15%. And most of these studies have involved beetroot, underpinning its stratospheric rise to vegetable greatness.
IS IT UNIQUE?
What’s often overlooked is that beneficial nitrates certainly aren’t exclusive to beetroot. In fact, many other fruit and vegetables contain more. On a weight for weight basis, rocket leaves supply almost four times the amount of nitrates found in fresh beetroot and it just about makes the top 10 of nitrate-rich foods with Swiss chard, oak leaf lettuce and rhubarb all providing higher levels.
Even Andy Jones, professor of applied physiology at the University of Exeter and the man who has conducted dozens of studies on the benefits of nitrates on performance, says: “It doesn’t have to be beetroot.” When it comes to performance-enhancement, the red root wins largely because of its convenience. “It’s not that it is better than other nitrate-containing foods, it’s the fact that it can be juiced to provide the concentrated, measured dose needed in laboratory settings and for the dietary precision required by athletes,” says Jones.
HOW MUCH DO YOU NEED?
Serious, competitive runners probably need somewhere in the region of 400g of nitrate-rich vegetables for a week or so prior to competition, along with the last-minute pre-event 70ml “shot” taken two to three hours before a race. More, says Jones, isn’t better as it has “a proven dose response”.
If you are just looking to better your health, then an intake of 100-300g a day of leafy green vegetables or fresh beetroot, will provide sufficient nitrate for positive effects on blood pressure and your heart.
Don’t bother buying organic varieties. “Where veg is grown and in what type of soil has a huge impact on its nitrate content,” Jones says. “Organic beetroot tends to contain less and many juice manufacturers use non-organic supplies for their higher nitrate products.”
Many find their urine undergoes a dramatic colour change. Cyclist Mark Cavendish summed it up when he coined the hashtag “p***ing rainbows” as he tweeted: “It doesn’t matter how often it happens, taking a pee the day after drinking beetroot juice will always freak you out”.
Since bacteria beneath the tongue is responsible for converting nitrate from food into active nitrates, no supplement or food will have the desired effect if used with an antibacterial mouthwash or gum. Both destroy the beneficial bacteria so that there is no performance response.
ARE THERE DOUBTERS?
Some researchers argue that investing in beetroot and nitrate supplementation is a waste of time and money. In one study, David Proctor, professor of kinesiology and physiology at Penn State University, measured blood flow and vessel dilation during a moderate-intensity handgrip exercise but found no improvements in blood flow to the exercising muscles after consuming two 70ml beetroot juice shots.
Another trial published in the journal Medicine and Science in Sports and Exercise found that a pre-run dose of potassium nitrate, the equivalent of that in beetroot, resulted in no improvements in oxygen efficiency or speed recorded in a 5km run.
WORTH A SHOT?
Ironically, beetroot shots are less likely to help high-performing sports people than the average gym-goer. “Most of our research indicates that the effects of dietary nitrates on endurance capacity and recovery are more pronounced in the average person than someone who trains hard for their sport and competes at a high level,” Jones says.
There are many possible explanations for why this is, although the most likely reason is that many of the physiological adaptations achieved by consuming nitrates are already evident in a serious athlete. Even then, some people are classed as “non-responders” to dietary nitrate, meaning they need a much larger dose than would normally be obtained in the diet to elicit any kind of response.
Taking beetroot is certainly not harmful. But don’t expect miracles.