Three weeks of supplementation with the juice led to reductions of systolic BP of 1.3 mmHg, report researchers in Nutrition Research, but the effects were not maintained after stopping consumption.
However, the benefits were only observed when blood pressure was measure at home, and not when 24-hr ambulatory BP monitoring (ABMP) was used, said researchers from Newcastle University and the University of Hertfordshire.
“In older, overweight subjects, beetroot juice supplementation was associated with beneficial effects on daily systolic BP, but the effects were not significant when measured by 24-hr ABPM,” they wrote. “The ability to detect an effect of beetroot juice concentrate supplementation in older, overweight subjects appeared to be influenced by the method that was used to measure BP. The daily monitoring of BP could represent a sensitive method to evaluate the efficacy of nutritional interventions on BP.”
The study adds to a growing body of science supporting the potential blood pressure benefits of beetroot juice, including a study published in Hypertension that found that the juice may decrease blood pressure by about 10 mmHg. A study from Australia reported that the juice was associated with a significant reduction in systolic blood pressure of 4 to 5 mmHg.
But it has been in the sports nutrition realm that there has been the most interest in beetroot following the news the Auburn University football team drinks the juice before its games. As reported in the Wall Street Journal, the team began using the ingredient mixed into their water bottles last year.
The majority of the science has been in support of the potential sports nutrition benefits of beetroot, linked to the nitrate concentration in the vegetable.
The England-based researchers recruited 24 overweight, older participants for their study. The volunteers were randomly assigned to receive either beetroot juice concentrate or blackcurrant juice for three weeks, and monitoring was continued for a fourth week.
Results showed that, while no significant effects were detected using the 24-hr ABPM or at the clinic, a significant reduction was observed in the daily systolic BP measurements taken at home.
“The underlying mechanism is most likely due to an increase in [nitric oxide] NO bioavailability, as a result of an increased non-enzymatic reduction of nitrate into nitrite and NO,” they wrote. “The association of inorganic nitrate with BP is shown by the rise of systolic BP within 24 hours after interrupting the supplementation, and the return to baseline after three days.
“These results suggest that continuous inorganic nitrate supplementation may be necessary in order to sustain beneficial cardiovascular effects.”
Source: Nutrition Research
Published online ahead of print, doi: 10.1016/j.nutres.2014.09.007
“Beetroot supplementation lowers daily systolic blood pressure in older, overweight subjects”
Authors: A. Jajja, A. Sutyarjoko, J. Lara, K. Rennie, K. Brandt, O. Qadir, M. Siervo