The ON-BC study Oral Nitrate supplementation & Blood pressure in COPD
Research type
Research Study
Full title
The ON-BC study: Oral Nitrate supplementation and Blood pressure in COPD – a randomised clinical trial
IRAS ID
271589
Contact name
Nicholas Hopkinson
Contact email
Sponsor organisation
Imperial College London
Duration of Study in the UK
2 years, 11 months, 30 days
Research summary
Research Summary
Background: Dietary nitrate supplementation, in the form of beetroot juice, has a number of potentially advantageous effects in COPD. These include improving the response to pulmonary rehabilitation programme, making muscle contraction more efficient so it uses less oxygen, and improving how far people with low oxygen levels because of their lung disease can walk. Although COPD is a lung disease, people with the condition are at a higher risk of heart disease and stroke. There is also some evidence that beetroot juice can reduce blood pressure, but studies so far have been short term. A nutritional treatment that could produce a lasting reduction in blood pressure would be appealing, especially if it also improves people’s ability to exercise.
Aims: The purpose of this study is to investigate the prolonged treatment effects of daily beetroot juice on blood pressure in people with COPD. We will also look at how far people can walk. We will make measurements of how well blood vessels function and take blood samples to look at the mechanisms involved including how “sticky” platelets are. These are the cells in the blood that cause it to clot.
Study Design: 72 patients with COPD will be enrolled in the study. Half will drink a 70ml beetroot juice “shot” each morning for three months. This contains 6.5mmol nitrate, the active ingredient. The other half will take identical juice drink which has had the nitrate removed. Which group participants are in will be decided at random by a computer. The main outcome will be blood pressure measured by participants at home for 4 days at the beginning and end of the study. In addition we will measure how far people can walk, how well blood vessels work using a device that measures blood flow, and blood tests looking at nitrate levels and platelet function. We will also collect mouth swabs to look at bacteria in the mouth to see if that changes with treatment. The study is funded by The Saudi Cultural Centre.
Expected outcome: If the study is positive this will help in the development of beetroot juice as a therapy for people with COPD and other long term conditions.
Summary of Results
Background: Previous short term studies suggest that dietary nitrate supplementation may improve cardiovascular risk, by lowering blood pressure (BP) and improving the way that blood vessels function. We wanted to see if these beneficial effects were sustained over a longer period in people with chronic obstructive pulmonary disease (COPD) who have a systolic blood pressure of at least 130.
What we did: Beetroot juice is rich in nitrate so we compared the effect of two beetroot juice drinks. The "active treatment" was a once daily 70ml drink of beetroot juice. The "control" drink was beetroot juice where the nitrate has been removed. The control drink looked and tasted exactly the same, so people taking part in the study and investigators running the trial did not know who was taking which drink.
A computer selected people at random to take one or other drink every morning for 90 days.
After 90 days, we compared blood pressure, exercise capacity (how far people could walk in 6 minutes) between the 40 people who had been taking the nitrate-rich beetroot juice and 41 people who were taking the placebo drink with the nitrate taken out.
What we found: The nitrate rich beetroot jucie lowered blood pressure (systolic blood pressure fell by 3mmHg) and improved show far people could walk in 6 minutes (by 30m). We also found that blood vessels in the arm became less stiff and more responsive.
What does it mean: In people with COPD, dietary nitrate supplementation in the form of beetroot juice produces a sustained reduction in blood presure, improves blood vessel function and increases exercise capacity over at least 90 days. This could reduce the risk of heart attacks and strokes and may improve day to day symptoms as well, so longer term studies are needed.REC name
London - West London & GTAC Research Ethics Committee
REC reference
19/LO/1660
Date of REC Opinion
13 Nov 2019
REC opinion
Favourable Opinion