Does beetroot juice lower blood pressure?
Medical researchers have recently returned to this plant product to investigate its effect on blood pressure and explore opportunities to put it to use in modern medicine and the home management of conditions.
Researchers have concluded that one glass of beetroot juice a day is enough to significantly reduce blood pressure in people with high blood pressure. They conducted a placebo-controlled trial with dozens of participants.
According to the Centers for Disease Control and Prevention (CDC), high blood pressure is either the primary cause of or contributes to more than 1,000 deaths in the United States every day.
Because of the widespread impact of high blood pressure, researchers are likely to investigate in some depth any simple dietary interventions that could potentially benefit the wider population.
High blood pressure is a serious public health concern. It increases the risk of more dangerous health conditions, such as heart attack, stroke, and chronic heart failure. High blood pressure is also a major risk factor for kidney disease.
Beetroot juice has been investigated for the powerful effect of its nitrate content on blood pressure.
Beetroot contains high levels of dietary nitrate (NO3), which the body converts into biologically active nitrite (NO2) and nitric oxide (NO). In the human body, NO relaxes and dilates blood vessels.
Other leafy vegetables, such as lettuce and cabbage, also have high levels of the compound. They take it up from the soil through their roots.
A meta-analysis of 16 trials was published in The Journal of Nutrition in 2013.
The researchers found that "Inorganic nitrate and beetroot juice supplementation was associated with a significant reduction in systolic blood pressure."
One major trial was carried out at Queen Mary University of London (QMUL) in the United Kingdom and published in the journal Hypertension. The research was funded by the British Heart Foundation.
They found the following results:
"This interesting study builds on previous research by this team and finds that a daily glass of beetroot juice can lower blood pressure in people with hypertension - even those whose high blood pressure was not controlled by drug treatment."
Dr. Shannon Amoils, British Heart Foundation, senior research advisor
For the trial, Prof. Amrita Ahluwalia of the vascular pharmacology department at QMUL and her colleagues recruited 64 people aged between 18 and 85 years.
Half of the participants were taking prescribed medication for high blood pressure but did not reach their target blood pressure, and the rest had been diagnosed with high blood pressure but were not yet taking medication for it.
The participants were randomly assigned to one of two groups. One group consumed a 250-milliliter (ml) glass of beetroot juice, and the other group had the same, except their beetroot juice was nitrate-free.
The nitrate-free beetroot juice was the basis of the placebo group.
All groups consumed the juice daily for 4 weeks. They were also monitored for 2 weeks before and after the study, bringing the total trial period to 8 weeks.
The trial was double-blind, which means neither the administering clinicians nor the patients knew whether the beetroot juice they were given was the placebo or the active supplement.
During the 4 weeks in which they were taking the juice, patients in the active supplement group, whose beetroot juice contained inorganic nitrate, experienced a reduction in blood pressure of 8/4 millimeters of mercury (mmHg).
The first figure is systolic pressure, generated when the heart is pumping, and the second figure is diastolic pressure, created when the heart is relaxing and filling with blood. The 8/4-mmHg reduction brought the blood pressure of many participants back into the normal range.
In the 2 weeks after they stopped drinking the juice, their blood pressure returned to the higher levels noted at the start of the study.
This is the first study that shows evidence of dietary nitrate supplementation's long-lasting benefit in a group of patients with high blood pressure.
High blood pressure is a common health issue in the U.S., and beetroot juice acts as a natural aid.
The patients in the active supplement group also experienced a 20 percent or so improvement in blood vessel dilation capacity, and their artery stiffness reduced by around 10 percent.
Studies show that these changes are linked to a reduced risk of heart disease.
There were no changes in blood pressure, blood vessel function, or artery stiffness in the placebo group.
The authors note that the reduction achieved in the active supplement group is close to that achieved by medication. The average reduction in blood pressure caused by a single anti-hypertension drug is 9/5 mmHg.
The study concludes:
"These findings suggest a role for dietary nitrate as an affordable, readily-available, adjunctive treatment in the management of patients with hypertension."
To put the importance of these findings in context: The authors note that large-scale observational studies show that for every 2 mmHg increase in blood pressure, the risk of death from heart disease goes up 7 percent and the risk of stroke by 10 percent.
Commenting on the findings, Prof. Ahluwalia says:
"This research has proven that a daily inorganic nitrate dose can be as effective as medical intervention in reducing blood pressure and the best part is we can get it from beetroot and other leafy green vegetables."
She says that one reason the findings are exciting is that they open up the potential for people with high blood pressure to increase dietary nitrate in a way that can be easily worked into their daily lives while still providing a positive benefit.
"It is hugely beneficial for people to be able to take steps in controlling their blood pressure through non-clinical means, such as eating vegetables," Prof. Ahluwalia adds. "We know many people don't like taking drugs life-long when they feel okay, and, because of this, medication compliance is a big issue."
"The possibility of using a natural product, rather than another pill, to help lower blood pressure, is very appealing," adds Dr. Amoils.
Prof. Ahluwalia advises that people looking to increase their daily nitrate intake should avoid boiling vegetables, as the nitrate dissolves in water. Instead, "steaming, roasting, or drinking in a juice all has a positive effect," she notes.
As for the next step in confirming the relationship between beetroot juice and blood pressure, she says this was a small trial. The next stage would be a larger study that tries to replicate the findings over a longer period with a much larger group of people who have high blood pressure.
Here is a link to a wide range of natural beetroot products. Please note that this will open an external site.