Did you know there’s a way to lower blood pressure without popping a pill? Well, there is and it’s as close as the produce aisle in your local supermarket, according to a study published online in the American Heart Association journal Hypertension.

Researchers have known that the juice of the common beet, a.k.a. the beetroot, reduces blood pressure, but now they know why. This benefit comes from the vegetable’s nitrate content, said Amrita Ahluwalia, PhD, professor of vascular biology at Queen Mary’s William Harvey Research Institute, the study’s lead author.

For the study, researchers at Queen Mary University of London gave either beetroot juice or nitrate capsules to two groups of otherwise healthy volunteers. Then they compared the effects on the participants’ blood pressure and cardiovascular system.

Scientists found that the juice and the nitrates were equally effective in reducing blood pressure within 24 hours. This means it’s the nitrates—also found in leafy green vegetables—that confer beetroot’s circulatory benefits.

“We also found that only a small amount of juice is needed—just 250ml [one pint]—to have this effect,” Ahluwalia said, “and that the higher the blood pressure at the start of the study the greater the decrease caused by the nitrate.”

Click here to read more about beetroot juice’s health benefits.