Dietary nitrate supplementation alters the oral microbiome but does not improve the vascular responses to an acute nitrate dose

Nitrate (NO3−) contained in food and beverages can transiently increase nitric oxide (NO) availability following a stepwise reduction to nitrite (NO2−) by commensal bacteria in the oral cavity. We tested the hypothesis that regular ingestion of dietary NO3− would influence the oral microbiome, the capacity to reduce NO3− to NO2− in saliva, and the vascular responses to an acute dose of NO3−. The abundance of bacterial species on the tongue, the availability of NO markers, and vascular function were assessed in 11 healthy males before and after 7 days of supplementation with NO3−-rich beetroot juice and a NO3−-depleted placebo. As expected, saliva and plasma NO2− and NO3− were significantly elevated after NO3− supplementation (all P