Body mass-normalized moderate dose of dietary nitrate intake improves endothelial function and walking capacity in patients with peripheral artery disease


Peripheral artery disease (PAD) is characterized by the accumulation of atherosclerotic plaques in the lower extremity conduit arteries, which impairs blood flow and walking capacity. Dietary nitrate has been used to reduce blood pressure (BP) and improve walking capacity in PAD. However, a standardized dose for PAD has not been determined. Therefore, we sought to determine the effects of a body mass-normalized moderate dose of nitrate (0.11 mmol nitrate/kg) as beetroot juice on serum nitrate/nitrite, vascular function, walking capacity, and tissue oxygen utilization capacity in patients with PAD. 11 patients with PAD received either nitrate supplement or placebo in a randomized crossover design. Total serum nitrate/nitrite, resting BP, brachial and popliteal artery endothelial function (flow-mediated dilation, FMD), arterial stiffness (pulse-wave velocity, PWV), augmentation index (AIx), maximal walking distance and time, claudication onset time, and skeletal muscle oxygen utilization were measured pre-and-post-nitrate and placebo intake. There were significant group x time interactions (p<0.05) for serum nitrate/nitrite, FMD, BP, walking distance and time, and skeletal muscle oxygen utilization. The nitrate group showed significantly increased serum nitrate/nitrite ($Δ$1.32$μ$M), increased brachial and popliteal FMD ($Δ$1.3% and $Δ$1.7%, respectively), reduced peripheral and central systolic BP ($Δ$-4.7mmHg and $Δ$-8.2mmHg, respectively), increased maximal walking distance ($Δ$92.7m) and time ($Δ$56.3s), and reduced deoxygenated hemoglobin during walking. There were no changes in PWV, AIx, or claudication (p>0.05). These results indicate that a body-mass normalized moderate dose of nitratemay be effective and safe for reducing BP, improving endothelial function, and improving walking capacity in patients with PAD.

American Journal of Physiology-Regulatory, Integrative and Comparative Physiology