Nitrates are found concentrated in vegetables that grow in the nitrate rich soil, so as a whole, all vegetables are relatively high in nitrates. This said, it is particularly abundant in beetroot and leafy green vegetables, making these little beauties an important staple of our diet…especially an athletes!
Nitrates role in sport and exercise
Our understanding of how nitrates impact on our bodies is ever growing which is in part thanks to a spike in fund allocation. This spike is mainly attributed to the successful use of nitrate based supplements during the 2012 Olympic games, with athletes reporting better endurance, concentration and reduced perceived exertion when competing. In fact, Tipton and Luc van Loon, (2013) state that nitrates could potentially extend time to exhaustion by 16-25%, whilst the addition of beetroot juice/powder saw a 5% decrease in VO2 max during steady state exercise (Larsen et al. & Bailey et al.). Don’t get me wrong, the athletes weren’t getting this ergogenic effect (performance enhancing) based on their vegetable intake alone, instead they would combine this with a concentrated source of nitrates in the form of a beverage, usually beetroot. Consequently beetroot and the consumption of nitrates has received huge recognition and praise in the fitness and sporting industry.
How do Nitrates work?
Nitrates are only part of the process, nitrates (NO3) in their original state will not induce an ergogenic effect if it isn’t then reduced to nitrites (NO2) and nitric oxide (NO). NO is the main physiological signalling molecule that can modulate muscle function by regulating blood flow, muscle contractility, glucose and calcium balance and mitochondrial respiration and biogenesis (energy production). So nitrates are the pre- cursor to the production of NO in the body, and NO is the key to EXTENDING TIME TO EXHAUSTION. Dietary nitrate is readily absorbed into the blood from the stomach and small intestine, with approx 25% of the nitrate entering your circulation via the mouth (enterosalivary circulation). This happens via bacteria on the tongue which turns nitrate into nitrite, which once swallowed is turned into nitric oxide where it can exert its vasodilatory effects (widens blood vessels). This means that more oxygen can reach the bodies major tissue such as the brain, heart, lungs and muscles. As a result, the oxygen cost of sub- maximal exercise is reduced which improves training efficiency.
Where do supplements come in?
As mentioned before, nitrates are found in all plant sources, but you’d need to consume a large amount of these in order to meet the quantities needed to invoke an ergogenic effect. Therefore sport supplements that contain the NO precursor, L- arginine and/ or nitrates (such as beetroot juice) are good options. NO can be synthesised via 2 main pathways: the oxidation of L- arginine via endothelial nitric oxide synthase (NOS), and from the reduction of nitrate derived nitrite, to nitric oxide. Supplements will usually provide either inorganic nitrate found in food sources and food derived supplements such as beetroot juice, vegetables and nitrate salts (Beet it shots and Optimum Health Beetroot Powder). Many pre-workout supplements will deliver nitrates or nitric oxide precursors such as L- arginine. Alternatively there are organic nitrates such as the drugs nitroglycerine and amyl nitrite which are pharmaceuticals and not to be used as supplements/ ergogenic aids, commonly used in the treatment of angina and other cardiovascular related issues. The wrongful use of organic nitrates and nitrites can easily result in vascular collapse which could be fatal, so DO NOT attempt to use these for sporting or fitness endeavours. Inorganic nitrates such as beetroot juice and l-arginine can be used to improve sporting and fitness capacity safely, however care should always be taken, recommended dosages must be recommended and you should always consult your Doctor first if you have an underlying medical condition (especially a heart issue).
Tipton, K, D. & Luc Van Loon, J, C. (2014). Nutritional coaching strategy to modulate training efficiency. Nestle Nutrition Institute. Basel: Karger
Today’s Dietitian, (2014). Reap the Benefits of Beetroot Juice — Evidence Suggests It Improves Heart Health and Athletic Performance. Retrieved 17th June, 2014, from http://www.todaysdietitian.com/newarchives/020612p48.shtml