Feb. 8, 2008 -- Drinking two cups of beet juice a day may reduce blood pressure, a study shows.
That's because beets (known as beetroot in Britain) are loaded with the nutrient nitrate. Spinach, lettuce, and other green, leafy vegetables also have high levels of nitrate.
Previous studies have shown that eating a diet high in fruits and vegetables lowers blood pressure. Antioxidants often get the credit, but several recent studies have suggested that nitrates may play a much bigger role. How nitrates work to lower blood pressure has been more of mystery.
How Nitrates May Lower Blood Pressure
In the study, 14 healthy volunteers drank 500 milliliters (2 cups) of Planet Organic beet juice or water within 30 minutes. The researchers checked the participants' blood pressure every 15 minutes one hour before they drank the juice and every 15 minutes three hours after drinking the beet juice. They also checked every hour to six hours and then at 24 hours after they drank the beet juice.
Compared with the water drinkers, blood pressure dropped one hour after the volunteers drank the beet juice. It reached its lowest point 2.5 to 3 hours after ingestion and continued to have an effect for up to 24 hours.
Here's how it works: Nitrate in the beet juice is converted by bacteria living on the tongue into the chemical nitrite. Once it enters the stomach, it becomes nitric oxide or re-enters the blood stream as nitrite. The researchers found that blood pressure was at its lowest when the nitrite levels in the blood were at their highest.
The nitrites, the researchers write, work by protecting against endothelial dysfunction, which means that blood vessels have trouble expanding or contracting to handle changes in blood flow. They also have anti-platelet properties.
"Our research suggests that drinking beetroot juice, or consuming other nitrate-rich vegetables, might be a simple way to maintain a healthy cardiovascular system, and might also be an additional approach that one could take in the modern-day battle against rising blood pressure," says Amrita Ahluwalia, PhD, one of the study's researchers. Ahluwalia is a professor at the William Harvey Research Institute at Barts and The London School of Medicine.
The study is published in the Feb. 4 online edition of the journal Hypertension.