The main challenge for humans visiting high altitude (HA) is the reduced oxygen availability in the air (“thin air”). How well humans tolerate HA is highly variable, but in order to minimize the risk of developing the feared symptoms of acute mountain sickness (AMS), proper acclimatization is needed. The first symptoms of AMS are “self-limiting forms” like severe headache, tiredness and vomiting, but improper acclimatization can lead to the potentially lethal forms like high-altitude cerebral -and pulmonary edema (HACE/HAPE). Vital in a successful acclimatization is that the blood vessels are able to deliver enough oxygen throughout the body. Previous research have shown that blood vessels tend to contract in HA, thereby we wanted to investigate if we could improve blood vessel function in HA simply by drinking beetroot juice at 3700 meters of altitude. Blood vessel function was measured through a standard test of arterial endothelial function by a flow mediated dilatation test (FMD) using ultrasound.
Read about the study in Scientific American here!
Read about this study in Gemini here!
In a study we recently published in Nitric Oxide: Biology and Chemistry we show that consumption of organic nitrate-rich beetroot juice restores reduced blood vessel function at high altitude (HA). The reasearchers behind the study is from us K.G. Jebsen Center of Exercise in Medicine (CERG) at the Norwegian University of Science and Technology (NTNU) and Mid Sweden University, Östersund, Sweden.
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Normal blood vessel function depends on the body’s ability to naturally produce a compound called nitric oxide (NO). In healthy people at sea level production of adequate amounts of NO is not a problem, but in HA with reduced oxygen availability this is a challenge, simply because natural NO production requires oxygen. But the body has a “back-up system” for NO production at altitude, and it is here beetroot juice has its function. The secret behind beetroot juice is that it contains high amounts of nitrate that is converted to NO in the body.
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Before CERG at NTNU and the Mid Sweden University went on a 39 days expedition to Nepal no one had studied if consumption of a nitrate rich juice could have positive effects on blood vessel function in HA. In both male and female blood vessel function was studied with ultrasound before and during a high altitude expedition. As expected, HA made blood vessels contract. To test if beetroot juice could make the blood vessels relax again, people were investigated after drinking two types of beetroot juice with a 24-hour brake in-between tests. One of the juices contained high amounts of nitrate while the other type had no nitrate in it (placebo). It is important to state that neither test persons nor the researchers knew what type of beetroot juice each person drank before the blood vessels was investigated, and the order of the juice were given randomly.
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Our study showed that beetroot juice with high amounts of nitrate made the blood vessel relax, and return to normal function, while beetroot juice with no nitrate (placebo) did not have any effect. When you plan your next trip to HA, maybe it is worth carrying a bottle of beetroot in your backpack. It may be the extra boost your body needs to deliver enough oxygen to your tired muscles and keep you healthy when you are climbing a high mountain.
Svein Erik Gaustad, Postdoctor at CERG