A recent article published in PLoS ONE examines the dietary benefits of beetroot juice on the health of the airways and the immune system.
Beetroot, commonly known in North America as beets, is a common vegetable rich in dietary nitrate. Nitrates from the diet are normally converted to nitrite, and then further reduced to nitric oxide (NO), which is a compound that stays in our blood and tissues. Nitric oxide plays a role in the innate immune response in the airways, which act to prevent and control viral and bacterial infections in the lung.
One way by which we can measure nitric oxide in the airways is through exhaled air. Previous animal studies have demonstrated a correlation between a reduced production of nitric oxide and less protection in the airway. Moreover, studies have shown that dietary nitrate and beetroot juice can improve exercise performance and even reduce blood pressure long-term. Studies have tested nitric oxide levels in exhaled air after beetroot juice consumption, but only in the context of an exercise challenge for males, under low-oxygen conditions.
Can Beetroot Juice Affect Nitric Oxide Levels?
An American group of researchers aimed to gain a better understanding of how beetroot juice influences nitric oxide levels in the airway under normal conditions among both genders in order to guide future research on the ability of beetroot juice to improve respiratory health. Their findings were recently published in PLoS ONE, demonstrating the effects of beetroot juice on nitric oxide levels in the airway.
In total, 23 male and 15 female healthy, non-smokers participated in this study. They were asked to refrain from exercising or eating for one hour before the ingestion of 70 mL of beetroot juice for the study. An electrochemical analyzer was employed to measure the nitric oxide levels of their exhaled air. The participants’ nitric oxide measurements, heart rates, and blood pressures were taken at baseline, 45 minutes after drinking the juice, and 90 minutes after drinking the juice.
Nitric Oxide Levels Increased After Consuming Beetroot Juice
The authors of this study observed that nitric oxide in the exhaled air increased significantly after the beetroot juice consumption at both the 45-minute mark and 90-minute mark. There were no noticeable cardiovascular effects of the juice, however.
This study showed the ability of one dose of beetroot juice in a normal setting to significantly increase nitric oxide levels in the airway, similar to what other studies have shown before. Importantly, the effect was sustained for at least 90 minutes and potentially longer, especially with multiple, larger doses of beetroot juice.
Airway nitric oxide levels can have implications for allergic diseases and airway infections due to its role in the innate immune defence. Further studies can build upon this study to see if elevations of nitric oxide levels in the airways, from consuming beetroot juice, can boost the innate immune system and provide protective effects to the airways.
Written by Branson Chen, BHSc
Reference: Kroll JL, Werchan CA, Rosenfield D, Ritz T. Acute ingestion of beetroot juice increases exhaled nitric oxide in healthy individuals. PloS One. 2018 Jan 25;13(1):e0191030.