Beetroot juice lowers blood pressure — but only in some people
Beetroot juice has been a recurring topic in nutrition research for years, consistently showing up in studies on blood pressure. But one question kept going unanswered: why does it work for some people and not others?
A team from the University of Exeter just answered that. Their study, published in May 2026 in Free Radical Biology and Medicine, shows the mechanism runs through the bacteria living in your mouth — and age is what determines whether it works.
How nitrate becomes nitric oxide
Beetroot is rich in dietary nitrate. When you drink beetroot juice, those nitrates hit your mouth and gut. But for your body to benefit, oral bacteria need to convert nitrate into nitrite first. That nitrite then enters the bloodstream, where it's converted into nitric oxide (NO).
Nitric oxide relaxes blood vessel walls and improves circulation. It naturally declines with age — which is one reason blood pressure tends to creep up as people get older.
The catch: this conversion only happens if you have the right bacteria in your mouth. And that's where age comes in.
What the study actually found
Researchers compared older adults — who had higher baseline blood pressure — to healthy adults under 30. Both groups drank high-nitrate beetroot juice twice a day for two weeks.
In older adults: blood pressure dropped significantly. In under-30s: no effect.
Saliva samples revealed why. In older participants, the beetroot juice had shifted the oral microbiome. Neisseria bacteria — known to efficiently convert nitrate — increased. Prevotella, which is less effective at that conversion, decreased. Those shifts didn't happen the same way in younger participants, explaining the absent blood pressure response.
What this means practically
Beetroot juice isn't a universal blood pressure fix. Its effectiveness depends on your oral microbiome composition, which shifts with age.
If you're over 50 and your blood pressure is running a bit high, two glasses of beetroot juice daily for a couple of weeks could have a real measurable effect. For younger healthy adults, the blood pressure benefit is probably minimal.
One important note from the researchers: beetroot juice is not a replacement for blood pressure medication. It's a complementary dietary strategy, not a treatment.
Source: University of Exeter, May 2026