A new study published just last month in the journal Hypertension suggests that drinking just one glass of beetroot a day can reduce blood pressure.
The study was conducted by researchers at Queen Mary University of London, Barts and The London School of Medicine and Dentistry. It involved eight women and seven men who had high blood pressure and who were not taking blood pressure medication.
Blood pressure is normally given as two numbers, which represent ‘systolic’ and ‘diastolic’ pressure levels. The first number, the systolic level, is a measure of the pressure created in the arteries when the heart beats. Normal systolic blood pressure is 120 millimeters of mercury (mm Hg) or below.
The second number, the diastolic level, represents the pressure in the arteries when the heart rests between beats. Normal diastolic blood pressure is 80 mm Hg or below.
The study participants all had raised systolic blood pressure of between 140 and 159 mm Hg.
The beetroot juice in the study provided about 0.2g of dietary nitrate, levels that might be provided by two beetroots. Nitrate reduces blood pressure by widening the passageways for blood. The body converts dietary nitrate into a chemical called nitrite and then to nitric oxide in the blood. Nitric oxide is a gas that widens blood vessels and aids blood flow.
The study involved eight women and seven men who had a systolic blood pressure between 140 to 159 millimeters of mercury (mm Hg), did not have other medical complications and were not taking blood pressure medication. The study participants drank 250 mL of beetroot juice or water containing a low amount of nitrate, and had their blood pressure monitored over the next 24 hours.
Compared with the placebo group, participants drinking beetroot juice had reduced systolic and diastolic blood pressure. The reduction was highest three to six hours after drinking the juice. Interestingly, blood pressure was still reduced 24 hours later, even after levels of nitrate circulating in the blood had returned to normal.
Study leader Amrita Ahluwalia, Ph.D., professor of vascular pharmacology at The Barts and The London Medical School, was surprised by how little nitrate was needed to produce these results. "This study shows that compared to individuals with healthy blood pressure much less nitrate is needed to produce the kinds of decreases in blood pressure that might provide clinical benefits in people who need to lower their blood pressure.”
Those drinking beetroot juice should be aware that this juice can cause a temporary pink colouration of urine and stools, which can be a little alarming but is completely harmless. Of course beetroot is not the only nitrate-rich vegetable. For those who don’t enjoy the taste, try nitrate-rich lettuce, rocket, spinach, celery, cabbage or fennel.
Increasing dietary intakes of nitrates is simple. Try adding beetroot juice to a smoothie, or lunch on beetroot soup. Use spinach and lettuce as salad bases, or snack on celery with hummus or peanut butter during the daytime. At dinner, include nitrate-rich vegetables such as bok choy, cabbage, leeks and broccoli.
"Our hope is that increasing one's intake of vegetables with a high dietary nitrate content, such as green leafy vegetables or beetroot, might be a lifestyle approach that one could easily employ to improve cardiovascular health," said Amrita Ahluwalia.
She nevertheless advises caution in interpreting the results of this small study, as “we are still uncertain as to whether this effect is maintained in the long term.” It is hoped these preliminary findings might pave the way for more larger-scale studies in this area.
References 1. American Heart Association (2013, April 15). Drinking cup of beetroot juice daily may help lower blood pressure. ScienceDaily. Retrieved 28/04/13