If you have been a keen endurance athlete for some time, you may have heard stories of top athletes supping on Beetroot juice. Heck if Team Sky are on it, surely it must be doing something good right?
I heard about the potential benefits of beetroot juice supplementation a few years ago, but it sounded like a lot of hard work/cost for minimal gain. A pint a day for a week prior to a race. I doubted I could stomach that much let alone plan the logistics to be able to get that many litres of the stuff to or at a race location. I started off at home juicing it. It has to be raw for maximal benefit, but boy does it make a mess – especially in my hands. So being an impatient lass I quickly got bored with the time consumption needed to be a regular beet drinker.
But as time went on, more and more evidence popped up on just how good this stuff was. Simply put it makes your body use fuel more economically. Compare a Toyota Yaris to a Aston Martin DB9. You’ll go much further with your same amount in your tank in the Toyota (although it’ll be far less fun!).
Triathlon is largely an aerobic sport. (sprint efforts excluded)
Initially during increased exertion, muscle glycogen is broken down to produce glucose, which undergoes a number of chemical reactions involving Oxygen.
This produces carbon dioxide and water and releases energy. If there is a shortage of oxygen (such as when explosive movements are required), anaerobic metabolism (without oxygen) kicks in, but this is very inefficient & waste products rapidly accumulate. If the muscles can use less oxygen during aerobic metabolism to do the same amount of work – the caveat goes that the muscle will produce fewer waste products and hence take longer to fatigue.
The active component in Beetroot juice that affects oxygen utilisation during exercise is Nitrate. Nitrates are not exclusively found in Beetroot. They can be found in lettuce, beets, carrots, green beans, spinach, parsley, cabbage, radishes, celery. To be getting the recommended quantity of ‘performance enhancing’ nitrates you would have to be eating over 10 beetroots a day. Juicing is therefore more accessible form of consumption. Ingesting inorganic nitrite salts is not recommended and can be toxic.
How exactly nitrate (or more specifically the nitrite ion) interacts in the aerobic pathways responsible for energy production remains unknown, although a number of hypotheses have been proposed (the details of which are beyond the scope of this article but further details can be found here.
The original research paper concluded: Dietary nitrate supplementation reduced oxygen demand during submaximal exercise. This highly surprising effect occurred without an accompanying increase in lactate concentration, indicating that the energy production had become more efficient. More detail can found here.
Recent research at The University of Exeter took nine club-level competitive male cyclists and assigned them in a randomized, crossover design to consume 0.5 litres of beetroot juice (BJ) or 0.5 litres of nitrate-depleted beetroot juice as a placebo (PL), 2.5 hour before the completion of a 4 and a 16.1-km TT.
The BJ supplementation elevated plasma nitrite significantly, the VO2 values during the TT were not significantly different between the BJ and placebo conditions at any elapsed distance but BJ significantly increased mean POWER OUTPUT during the 4-km (PL = 279 ± 51 BR = 292 ± 44 W,) and 16.1-km TT (PL = 233 ± 43 BR = 247 ± 44 W).
BR improved 4-km performance by 2.8% and 16.1-km performance by 2.7%, the authors conclude dietary nitrate supplementation with 0.5 L of BR improves cycling economy, as demonstrated by a higher power output for the same VO2 (use of oxygen) and enhances both 4- and 16.1-km cycling TT performance.
Other studies have shown similar results and extrapolating from the data one could conclude that the benefits for endurance athletes could be extraordinary. Especially Ironman/Ultra-running.
The more efficient one is at exercising, the longer one can exercise without fatigue.
Health benefits extend further to reduction in blood pressure and peripheral vascular disease.
1) Logistics – 500mls of Beet juice for 3-7 days (another study showed a one off 500ml ‘bolus’ prior to exercise was not beneficial) is quite a lot to consume & the flavour is not to everyones tastes. In addition it can upset some people’s digestion & it will turn your body fluids pink. (This recently attracted a strange look from a doct during a recent doping urine test). You can get around this following my example and drinking Beet It Sports Shots, which have higher nitrate content but you can down it in one mouthful. See: http://www.beet-it.com/sport/
Nitrates are converted by salivia to nitrites. In excess they can be very harmful. Obtaining nitrate from beetroot and other vegetable sources only limits risk of reaching toxic values. More about that here
3) The Unknown.
We are yet to fully know how and why nitrates reduce the 02 ‘cost’ of exercise. Is the effect exponential – e.g. Do higher blood nitrate levels further improve exercise efficiency? Where is the cut off. Could this be something for doping control in the future? A word of warning here. For further information see this YouTube clip from researchers at Exeter University
I am happy to answer any questions/concerns on Twitter (@sportiedoc) or through my website – www.sportiedoc.com