Beetroot juice lowers blood pressure and alters oral bacteria in older adults, study finds

Researchers at the University of Exeter reported that daily intake of nitrate-rich beetroot juice lowered blood pressure and altered the oral microbiome in older adults in a short-term clinical trial, while younger participants did not show the same blood-pressure response.

The randomized, crossover trial enrolled 75 volunteers — 39 adults under age 30 and 36 adults in their 60s and 70s — who each completed two separate two-week treatment phases. In one phase participants consumed a daily shot of beetroot juice high in dietary nitrates; in the other phase they received a visually and taste-matched placebo shot that contained no added nitrates. Each treatment period was separated by a washout interval to allow participants’ systems to return to baseline.

Investigators used bacterial gene sequencing to profile microbes in participants’ mouths before and after each treatment phase. Among older adults who consumed the nitrate-rich juice, the researchers observed a reduction in the abundance of Prevotella species and other shifts in oral bacterial communities. Those same older participants experienced reductions in blood pressure after the nitrate-containing treatment; younger participants did not demonstrate a comparable blood-pressure change in this short trial.

The paper, published in the journal Free Radical Biology and Medicine, ties the findings to the biochemical pathway by which dietary nitrates can be converted by oral bacteria into nitrite and then to nitric oxide, a molecule that relaxes blood vessels and can lower blood pressure. The study aimed to examine whether age-related differences in the oral microbiome might influence how individuals respond to dietary nitrates.

Lead author details and specific numerical blood-pressure changes were not provided in the press materials. The trial’s crossover design, with each participant serving as their own control across treatments, strengthened within-person comparisons, while the sequencing approach provided a more detailed view of how the oral microbiome shifted over the intervention.

The results add to prior research that has linked nitrate-rich vegetables such as beetroot to short-term improvements in vascular function. Researchers and clinicians have previously noted that dietary nitrate can be a nonpharmacologic means to support blood-pressure control, particularly in specific populations or contexts, but investigators typically caution that effects can vary by dose, duration and individual biology.

The study was limited by its modest sample size and short treatment periods. Those factors, along with the trial’s focus on short-term responses, mean the findings will need confirmation in larger, longer-duration studies to determine whether the microbiome changes and blood-pressure effects persist and translate into sustained cardiovascular benefit.

The authors said the findings underscore an interaction between diet, oral microbiology and vascular health and support further research into whether modifying the oral microbiome or tailoring dietary nitrate interventions by age could improve outcomes. Clinicians and individuals interested in using dietary approaches for blood-pressure management should consider the broader clinical context and consult health professionals before making changes to treatment plans.