Researchers from Queen Mary University, London, believe the work is significant as high blood pressure is a growing problem worldwide. In addition, people are keen to control their blood pressure without using drugs.
In the study, drinking beetroot juice was shown to lower blood pressure while improving vascular (blood vessel) function. Consequently, researchers suggest a daily dose of beetroot juice or other nitrate-rich green leafy vegetables, "can be as effective as medical intervention in reducing blood pressure".
High blood pressure on a ‘worrying’ scale
Each increase of 2mmHg (millimeters of mercury) in blood pressure is understood to increase the likelihood of death from heart disease by 7% and stroke by 10%.
“Systematic hypertension [raised blood pressure] remains the largest attributable risk factor for mortality worldwide,” lead author Amrita Ahluwalia (pictured) writes.
“Worryingly, the scale of the problem is increasing, with the proportion of adults with hypertension predicted to increase to almost one in three by 2025," she adds.
“Novel therapeutic strategies including dietary approaches are of great interest.”
250ml daily beetroot juice dose
Beetroot – alongside other leafy green vegetables such as lettuce and cabbage – contain high levels of inorganic nitrate.
In the study, half the participants were taking prescribed anti-hypertensive drugs but were not reaching their target blood pressure. The other half had high blood pressure but were not on medication.
Participants were assigned to either drink a daily 250ml portion of James White Drinks' beetroot juice over four weeks, or consumed a placebo. Those drinking beetroot juice showed an average decrease in blood pressure of about 8/4mmHg, which, for most patients, brought levels back to normal.
Participants drinking beetroot juice also showed an improvement of around 20% in blood vessel dilation capacity, and around a 10% reduction in arterial stiffness. Other studies show this is associated with reduction in heart disease.
Nitrate-rich vegetables: Cost effective, affordable, favorable
“The potential importance of our findings is substantial when one considers each 2mmHg increase in systolic blood pressure increases mortality because of ischemic heart disease and stroke by 7% and 10% respectively,” Ahluwalia writes.
“Although the time frame of the study is too short to make any supported claims to long-term blood pressure control, this data is the first to demonstrate robust, sustained blood pressure lowering with dietary nitrate in patients with hypertension that require blood pressure control (rather than healthy subjects)," she adds.
“As such, the study is encouraging and should spur large-scale, long term outcome studies.”
“With large populations of inadequately treated patients with hypertension at higher risk of cardiovascular disease, an additional strategy, based on intake of nitrate-rich vegetables, may prove to be cost-effective, affordable, and favorable for a public health approach to hypertension," Ahluwalia writes.
The study was funded by the British Heart Foundation.
The next step is to run a large-scale phase clinical trial to determine whether dietary nitrate maintains an impact over a longer period, and whether it should be recommended in NHS guidelines.
Title: 'Dietary nitrate provides sustained blood pressure lowering in hypertensive patients'
Authors: Kapil, V, Khambata, R.S., Robertson, A., Caulfield, M.J., Ahluwalia, A.
Source: Hypertension, February 2015, Published online before print November 24, 2014, doi:10.1161/HYPERTENSIONAHA.114.04675