Acute blood pressure lowering, vasoprotective, and antiplatelet properties of dietary nitrate via bioconversion to nitrite.
Level 2 - randomized trial
Individual randomized trial testing acute dietary nitrate ingestion and salivary pathway interruption in healthy humans
PubMed 18250365 · doi:10.1161/HYPERTENSIONAHA.107.103523
What was done
Healthy human volunteers ingested a 500 mL dietary nitrate load (beetroot juice). Investigators measured blood pressure, plasma nitrite concentrations, endothelial function after an acute forearm ischemic insult, and ex vivo platelet aggregation in response to collagen and ADP. The role of oral bacterial bioconversion was tested by interrupting the enterosalivary conversion of nitrate to nitrite.
What was found
Approximately 3 hours post-ingestion, blood pressure fell by a maximum change of -10.4/8 mm Hg, correlating with peak increases in plasma nitrite concentration. The nitrate load also prevented ischemia-induced endothelial dysfunction and significantly attenuated ex vivo platelet aggregation. Interrupting enterosalivary conversion prevented the rise in plasma nitrite, blocked the blood pressure reduction, and abolished the inhibitory effects on platelet aggregation.
Why it matters
This study identifies the enterosalivary bioconversion of dietary nitrate to nitrite as a functional mechanism by which vegetable-rich diets can acutely reduce blood pressure, protect endothelial function, and inhibit platelet aggregation.
Limits
The abstract does not state the sample size (n), participant demographics beyond being healthy volunteers, or numeric values for endothelial function and platelet aggregation outcomes. It evaluates only acute responses to a single load, so long-term efficacy and safety in hypertensive or clinical populations cannot be determined from these data.
Cited by
- supports Oral bacteria reduce dietary inorganic nitrates found in vegetables like beets and arugula into nitrites, which subsequently enter the nitric oxide pathway to promote vasodilation.