The theory is that consuming beetroot juice has a positive impact on one’s health and athletic performance. This is believed to be due to its high nitrate concentration for which the body converts into nitric oxide. Nitric oxide has been shown to reduce blood pressure at rest, suggesting benefits for improving one’s cardiovascular health. Furthermore, it potentially plays a role in reducing the oxygen cost of exercise, which could lead to an enhanced athletic performance. The supplementation of beetroot juice could potentially allow an athlete to train at the same intensity for longer or to train at an elevated intensity for the same duration, helping to obtain a greater adaptation response from the muscles.
Proposed pathway
The original source of NO3 (nitrate), found in beetroot juice, which is reduced in the mouth by anerobic bacteria to NO2 (nitrite). This is then transported to the stomach where it is reduced further. The remaining nitrate and nitrite are then absorbed through the gastrointestinal tract. This is where it becomes the bioactive compound (NO), in the tissue and blood. (NO) can induce a range of physiological effects in skeletal muscle; including vasodilation, aiding in improving and regulating blood flow, and getting nutrients and oxygen to where it’s needed. Mitochondrial biogenesis, which is the process whereby cells increase mitochondrial mass, potentially leading to an increased glucose uptake.
This should allow for better muscular contraction and relaxation. In theory making muscles more efficient, potentially postponing fatigue and justifying the reduction in oxygen cost. Although the benefits aren’t limited to athletic performance.
Additional benefits to consuming beetroot
Beetroot and its leafy greens are rich in potassium, magnesium, fibre, phosphorus, iron, beta-carotene, folic acid and vitamins A, B and C. Specifically, the root is the source of all forms of B vitamins as well as the potassium, magnesium, iron and manganese. Betalains are phytonutrients found in plants that give beetroots their characteristic red colour. As an antioxidant they have been shown to reduce inflammation and its vulgaxanthin content, support detoxification. Studies have also associated betalains with reducing cancer risk and lessening tumour cell growth. Betalains are highly concentrated in the peel and flesh of the beet. The presence of betaine, a choline-derived nutrient which helps protect cells, enzymes and proteins from environmental stressors, gives beetroots the ability to fight inflammation. Moreover decreasing, homocysteine concentration, that comes from the consumption of dietary betaine has been associated with lowered markers for systemic inflammation. On the cellular level, its anti-oxidants and iron concentration help fight free radicals and tumour growth associated with cancer.
Timing and dosage
Work done by Lee J Wylie in 2013 suggests that allowing 2-3 hours before the start of exercise should be adequate. Next is there a threshold amount or a ceiling for which one would reach a point of diminishing return? The dosages were set at 70ml (around 4mmol nitrate), 140ml (around 8 mmol of nitrate) and 280ml (around 16mmol of nitrate). It’s important to note in every category, an improvement in time to failure was observed but the 140ml group seemed to gain the most in terms of the benefits.
Evidence
A study conducted by Andre Jones at the university of Exeter in 2014 supported the evidence suggesting that beetroot intervention can lead to a greater muscle efficiency allowing athletes to have a higher power output and running speed whilst maintaining a similar Vo2 recording.
Research done by Filip J Larsen in 2011 suggests that dietary nitrates, not just from beetroot but also other high nitrate content food, have a profound effect on mitochondrial function, reducing oxygen cost during exercise, implying one can maintain a certain level of intensity with a decreased level of perceived exhaustion.
Research by Raul Domínguez in 2017 also suggest (NO) could help with hypertension and heart failure.
In a study conducted by Harald Engan in 2012 concluded that free divers could hold their breathe for up to 30 seconds longer after a single dose of beetroot juice.
Daryl Wilkerson conducted a study in 2012 on trained cyclist and found that with beetroot supplementation, performance increased by about 0.8% in a 50-mile test. With special mention to the last 10-miles where a significant increase in efficiency was observed.
It’s important to note a large percentage of these studies were performed on men, however a study conducted by Vernon Bond Jr in 2013 at Howard University, Washington had a vastly diverse sample of females also suggests the effects of beetroot supplementation work in the same way for women.
If you’ve found this article interesting and would like any additional reading on the topic, I have provided some of my sources:
https://www.nrcresearchpress.com/doi/abs/10.1139/apnm-2014-0036#.Xr9G4mhKhPZ
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5295087
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5295087
https://www.ncbi.nlm.nih.gov/pubmed/22588047
https://www.ncbi.nlm.nih.gov/pubmed/22526247
https://www.nrcresearchpress.com/doi/abs/10.1139/apnm-2013-0263#.Xr9H5GhKhPZ>
https://journals.physiology.org/doi/full/10.1152/japplphysiol.00372.2013
