Safety and efficacy of sodium nitrite supplementation for improving vascular endothelial dysfunction in middle-aged and older healthy adults (698.4)

Vascular endothelial dysfunction develops with aging as a result of insufficient nitric oxide (NO) bioavailability. Supplementation with nitrite, a precursor to NO, may improve NO bioavailability. We tested the safety, dose (80 vs. 160 mg/d), duration (4 and 10 weeks), and efficacy of oral sodium nitrite for improving endothelial dysfunction in middle-aged and older (MA/O) adults (n=28, 61±1 yr) in a randomized, placebo-controlled, double-blind pilot intervention study. Both doses of nitrite acutely increased plasma nitrite (10 to 20-fold, p<0.05) and were well-tolerated without symptomatic hypotension or clinically-relevant elevations in blood methemoglobin (maximal value=1.2%). Ten weeks of nitrite capsules chronically increased plasma nitrite (p<0.05, both doses) without altering blood pressure. Endothelial function, measured by brachial artery flow-mediated dilation (FMD), was increased 55-65% vs. baseline (p<0.05) after 10, but not 4 weeks of nitrite vs. placebo. The reduction in FMD with 20 min of f...