Overview

• The University of Exeter double-masked crossover study enrolled 75 adults who completed two-week phases of nitrate-rich beetroot juice and a nitrate-depleted placebo separated by washouts.
• Older participants experienced significant blood-pressure reductions after the nitrate-rich juice, whereas younger adults showed no meaningful change.
• Sequencing revealed age-specific microbial shifts, with decreases in Prevotella and increases in Neisseria in older adults correlating with higher plasma nitrite and lower blood pressure.
• A twice-daily antiseptic mouthwash phase reduced oral microbial diversity and impaired vascular responsiveness in younger participants, indicating oral hygiene practices may affect nitrate-related benefits.
• Investigators reported no change in endothelial function or arterial stiffness and called for larger, longer studies before clinical recommendations are adjusted.