Beetroot juice can battle altitude sickness: Himalayan study
Nitrate-rich foods like beetroot, spinach or some lettuces or supplements boosted blood vessel function and could reduce the risk of acute mountain sickness (AMS) at high altitude, researchers at the Norwegian University of Science and Technology (NUST) and Mid-Sweden University found.
The double-blind, randomised controlled crossover study in the Himalayas found less AMS in those on nitrate-rich beetroot juice. Beetroot juice is high in nitrate, which the body can convert to nitric oxide – a compound that enables normal blood vessel function, but that the body struggles to produce at high altitude due to the lack of oxygen inhaled.
AMS symptoms include headache, dizziness, insomnia and extreme fatigue can defeat the strongest of climbers.
Not a substitute for acclimatisation
While the results indicate a potential beneficial effect, the study was carried out on just eight subjects and had some limitations due to logistical restrictions and, therefore, a much larger scale investigation would be needed to confirm the potential role of beetroot juice, and specifically, nitrate, in preventing altitude sickness.
Svein Gaustad, joint first author of the study and postdoctoral fellow at the Cardiac Exercise Research Group (CERG) at the Norwegian University of Science and Technology (NTNU), told Nutraingredients: “This is a small study and more studies must be conducted before use of dietary nitrate supplementation eventually can be recommended in high altitude environments. Beetroot juice is not a substitute for acclimatisation in high altitude – people should follow the current guidelines for acclimatisation. The results from the study are exiting and raise several interesting research questions regarding the use of dietary nitrate supplementation at high altitude. We are applying for funding for future altitude studies.”
Impact on blood vessel function
In the study published in Nitric Oxide: Biology and Chemistry, the researchers measured blood vessel function with a standard test of arterial endothelial function, a flow-mediated dilatation test (FMD) that uses ultrasound.
Both men and women were studied to check their blood vessel function, before and during the high altitude expedition. At high altitude, the blood vessels contracted – which the researchers had expected. To test the hypothesis that beetroot juice could make the blood vessels relax again, the test subjects were investigated after drinking two types of beetroot juice with a 24-hour break between tests.
One of the juices contained high amounts of nitrate (0.5 mmol) while the placebo juice had no nitrate in it.
The study showed that beetroot juice with high amounts of nitrate made the blood vessels relax and return to normal function at high altitude, while the placebo juice did not have any effect. Specifically, the researchers found that: ‘dietary nitrate supplementation with beetroot juice restored FMD of the brachial artery to pre-trek levels by enhanced [nitrate]-mediated dilation in healthy lowlanders while at high altitude.’
Given that current treatments for AMS include prescription drugs such as acetazolamide and dexamethasone that have unpleasant side-effects including nausea, diarrhoea, fatigue, frequent urination, fever, possible kidney and liver toxicity, ulcers, cataracts, and depression, finding a proven natural remedy such as this could be significant in facilitating human exploration. The potential of gingko biloba in preventing AMS has been highlighted by some researchers, but is also yet to be fully substantiated.
Source: Nitric Oxide: Biology and Chemistry
Vol. 50, 15 November 2015,pp 58-64. doi:10.1016/j.niox.2015.08.006
‘Acute dietary nitrate supplementation improves arterial endothelial function at high altitude: A double-blinded randomized controlled cross over study’
Authors: E. Bakker, A. Patrician, E. Schagatay, T. Karlsen, U. Wisløff, S. Gaustad