The dose-response effects of nitrate-rich beetroot ingestion on cardiovascular and endothelial function: a randomised...

Dietary nitrate (NO₃^-) supplementation has been reported to improve cardiovascular health, but beyond its effects on brachial artery blood pressure (BP), dose-response effects on other cardiovascular variables are unclear. This study assessed the effects of three acute NO₃^- doses (200 mg, 400 mg, 800 mg NO₃^--rich beetroot powder) on brachial and aortic BP, arterial stiffness and macrovascular endothelial function, in a double-blind, randomised, crossover design. Cardiovascular variables and venous blood samples were measured prior to (control) and 2.5 h post supplement ingestion. Dietary NO₃^- supplementation increased plasma [NO₃^-] and plasma [nitrite] but had no effect on cyclic guanosine monophosphate (cGMP) concentration. Arterial stiffness markers improved following all NO₃^- doses, with no between-dose differences. However, endothelial function only improved following 400 mg (+3.07% compared to control) and aortic systolic BP only improved following 800 mg (-4 mmHg compared to control) dietary NO₃^- supplementation. Acute NO₃^- ingestion improved some cardiovascular risk factors, including arterial stiffness, macrovascular endothelial function and aortic systolic BP with different dose-response effects, but had no effect on brachial BP or plasma [cGMP]. These findings improve our understanding of NO₃^- supplementation and cardiovascular function in healthy adults.