Drinking a couple of daily shots of vegetable juice could help older people lower their blood pressure, research suggests. Beetroot juice is rich in nitrate, a compound that plays a key role in some bodily functions and has been linked to reduced blood pressure and the healthy functioning of blood vessels. University of Exeter researchers believe it may have positive effects on heart health by causing changes to the bacteria present in the mouth.

Their study saw participants drink regular doses of nitrate-rich beetroot juice and, later, a placebo version with the nitrate stripped out. When they were drinking the beetroot juice, tests showed a noticeable decrease in the mouth bacteria Prevotella and an increase in the growth of bacteria known to benefit health such as Neisseria. 

Older participants also had higher average blood pressure at the start of the study, which fell after taking the nitrate-rich beetroot juice, but not after taking the placebo supplement.

Study co-author Professor Andy Jones, of the University of Exeter, said: “This study shows that nitrate-rich foods alter the oral microbiome in a way that could result in less inflammation, as well as a lowering of blood pressure in older people.

“This paves the way for larger studies to explore the influence of lifestyle factors and biological sex in how people respond to dietary nitrate supplementation.”

A 1L carton of beetroot juice is available from supermarkets including Sainsbury’s for around £3.

The study included 39 adults aged under 30 and 36 in their 60s and 70s, who spent two weeks testing each drink formulation.

Changes to the oral microbiome were seen in both age groups but blood pressure only fell among the older participants.

Study author Professor Anni Vanhatalo, also of Exeter, said: “We know that a nitrate-rich diet has health benefits, and older people produce less of their own nitric oxide as they age. 

“They also tend to have higher blood pressure, which can be linked to cardiovascular complications like heart attack and stroke. Encouraging older adults to consume more nitrate-rich vegetables could have significant long term health benefits.

“The good news is that if you don’t like beetroot, there are many nitrate-rich alternatives like spinach, rocket, fennel, celery and kale.”

The findings were published in the journal Free Radical Biology and Medicine.