Dylan Bowe | Last Updated – 30/12/2023 | 4 Minute Read
What are nitrates?
Dietary nitrates are growing in popularity as sports nutrition supplements. Nitrates are small molecules produced in the body to limited amounts (as a by-product of nitric oxide) and is obtainable In the diet via consumption of vegetables, particularly beetroot and other low vegetables such as spinach or rocket. This molecule is a strong regulator of blood flow and vasodilation via its metabolite nitric oxide (the body converts nitrate to nitric oxide) – as nitric oxide is a signalling molecule associated with several physiological functions involving blood pressure regulation, cardiovascular health, mitochondria production, oxidative stress, and skeletal muscle repair (Stamler and Meissner, 2001). Nitric oxide impacts exercise performance through several mechanisms: decreased fatigue during exercise, increased nutrient and oxygen delivery to the working muscles, and increased excretion of metabolic by products of high intensity exercise (Macuh and Knap, 2021). This article aims to discuss the benefits of dietary nitrates and how to effectively supplement them for health and performance.
Benefits
Nitric oxide and cardiovascular health
Blood pressure regulation:
Nitric oxide acts as a potent vasodilator, relaxing the smooth muscle cells lining blood vessels. This relaxation leads to vasodilation and a subsequent reduction in blood pressure. Studies have consistently shown that dietary nitrates can significantly lower blood pressure, making them a valuable dietary tool for individuals with hypertension or those at risk of developing it (jones)
Endothelial function:
Endothelial cells line the interior of blood vessels and are essential for regulating blood flow and vessel health. Nitric oxide produced from consumption of nitrates can enhance endothelial function, which can maintain the flexibility and integrity of blood vessels.
Sports performance
Enhanced mitochondrial efficiency:
Mitochondria, which are the cellular powerhouses responsible for energy production, operate more efficiently in the presence of nitric oxide. This improved efficiency allows muscles to generate more energy with less oxygen consumption, effectively delaying the onset of fatigue during sustained physical exertion.
Improved oxygen utilisation:
Nitric oxide helps optimise the utilization of oxygen during exercise. This is particularly beneficial in endurance sports such as long distance running or cycling, where maintaining an adequate oxygen supply to working muscles is crucial.
Increased blood flow to muscle:
Vasodilation induced by nitric oxide results in increased blood flow to muscles. This heightened circulation aids in the delivery of nutrients and removal of waste products from exercises, which may improve muscle function and endurance.
Reduced oxygen cost of exercise:
Dietary nitrates can reduced the oxygen cost of exercise, which means that individuals can sustain a given exercise intensity with less effort, potentially leading to better performance and prolonged endurance.
How to supplement:
Nitrate supplementation, whether coming from citrulline malate, sodium nitrate, or via foods such as beetroot juice, may temporarily reduce the body’s oxygen demand during exercise. This decrease in oxygen demand can result in improved exercises and muscle performance (examine 25).
The optimal dose of nitrate supplementation is around 0.1-0.2mmol/kg (6.4-12.8mg/kg), which is the range of:
450-900mg for a 70kg individual
600-1200mg for a 90kg individual
To achieve this, supplementation of nitrates via concentrated beetroot juice is often recommended and it is always important to start at the lower end of dosage recommendations and working your way up higher depending on your own body’s tolerance and response to the supplement. Many companies sell concentrated beetroot juice shots at 400mg per 50-70ml shot, which is a great starting point. These should be taken 1-3 hours before exercise, and up to 6 days prior to competition in order to achieve the most efficient response.
Along with beetroot juice, citrulline supplementation can also increase nitric oxide levels in the body. Citrulline increases the body’s arginine levels, and as arginine is the main substrate for the synthesis of nitric oxide, citrulline ingestion can indirectly increase nitric oxide production. In order to enhance sports performance, take 6000-8000mg of citrulline malate around one hour prior to exercise, and on days you don’t exercises, it can be broken up into smaller doses.
Potential considerations
It is important to be aware of potential risks when supplementing with high levels of nitrates, the main risk being gastrointestinal discomfort. Some individuals may experience GI discomfort when consuming nitrate-rich foods or supplements such as beetroot shots, therefore it is important to monitor individual tolerance and adjusting intake accordingly to help mitigate any issues.
Conclusion
Based on current literature, dietary nitrate supplementation represents an effective ergogenic aid for improving performance through various mechanisms and is useful in a variety of sports situations and exercise modalities. The effect of dietary nitrates is most pronounced in less trained individuals when taken acutely or chronically in the range of 300-1000mg nitrate 1-3 hours before exercise and primarily in the case of high intensity exercise with a duration of 10-20 minutes. Nitrate supplementation is less pronounced in well trained individuals (VO2max > 65ml/kg/min); however, it can still be desirable to gain a small improvement in performance especially if competing a high level (national or international). Foods such as beetroots and leafy greens contain large amounts of nitrates but it can be very difficult to get the amount needed for a positive response, and so supplements such as beetroot juice shots can represent a more convenient and accurate way of covering needs for nitrate – but supplement contamination must be considered (try to find supplements that are Informed Sport certified).
References & Further Reading
Bescos, R., Ferrer-Roca, V., Galilea, P. A., Roig, A., Drobnic, F., Sureda, A., … & Pons, A. (2012). Sodium nitrate supplementation does not enhance performance of endurance athletes. Medicine and Science in Sports and Exercise, 44(12), 2400-2409.
Domínguez, R., Cuenca, E., Matheu, A., García-Flores, L. A., & Mata-Ordoñez, F. (2017). Effects of beetroot juice supplementation on cardiorespiratory endurance in athletes. A systematic review. Nutrients, 9(1), 43.
Hoon, M. W., Johnson, N. A., Chapman, P. G., Burke, L. M., & Thésleff, T. (2013). The effect of nitrate supplementation on exercise performance in healthy individuals: a systematic review and meta-analysis. International Journal of Sport Nutrition and Exercise Metabolism, 23(5), 522-532.
Jones, A. M., & Ferguson, S. K. (2018). The potential role of nitrate supplementation in the management of cardiac risk factors. Current Opinion in Cardiology, 33(4), 440-446.
Lansley, K. E., Winyard, P. G., Bailey, S. J., & Vanhatalo, A. (2011). Dietary nitrate supplementation reduces the O2 cost of walking and running: a placebo-controlled study. Journal of Applied Physiology, 110(3), 591-600.
Macuh, M. and Knap, B. (2021) Effects of nitrate supplementation on exercise performance in humans: a narrative review. Nutrients, 13(9), p.3183.
Stamler, J.S. and Meissner, G. (2001) Physiology of nitric oxide in skeletal muscle. Physiological reviews, 81(1), pp.209-237.
