VasoActive Research Group, School of Health and Sport Sciences, University of the Sunshine Coast, Sippy Downs, QLD 4556, Australia.
School of Human Movement and Nutrition Sciences, University of Queensland, St Lucia, QLD 4072, Australia.
Nutrients. 2019 Apr 26;11(5):954. doi: 10.3390/nu11050954.
Aging is often associated with reduced leg blood flow, increased arterial stiffness, and endothelial dysfunction, all of which are related to declining nitric oxide (NO) bioavailability. Flow mediated dilatation (FMD) and passive leg movement (PLM) hyperaemia are two techniques used to measure NO-dependent vascular function. We hypothesised that acute dietary nitrate (NO) supplementation would improve NO bioavailability, leg FMD, and PLM hyperaemia. Fifteen healthy older men (69 ± 4 years) attended two experiment sessions and consumed either 140 mL of concentrated beetroot juice (800 mg NO) or placebo (NO-depleted beetroot juice) in a randomised, double blind, cross-over design study. Plasma nitrite (NO) and NO, blood pressure (BP), augmentation index (AIx75), pulse wave velocity (PWV), FMD of the superficial femoral artery, and PLM hyperaemia were measured immediately before and 2.5 h after consuming NO and placebo. Placebo had no effect but NO led to an 8.6-fold increase in plasma NO, which was accompanied by an increase in FMD (NO: +1.18 ± 0.94% vs. placebo: 0.23 ± 1.13%, = 0.002), and a reduction in AIx75 (NO: -8.7 ± 11.6% vs. placebo: -4.6 ± 5.5%, = 0.027). PLM hyperaemia, BP, and PWV were unchanged during both trials. This study showed that a dose of dietary NO improved NO bioavailability and enhanced endothelial function as measured by femoral artery FMD. These findings provide insight into the specific central and peripheral vascular responses to dietary NO supplementation in older adults.
衰老是与减少腿部血流、增加动脉僵硬度和内皮功能障碍相关联的，所有这些都与一氧化氮（NO）生物利用度的下降有关。血流介导的扩张（FMD）和被动腿部运动（PLM）充血是两种用于测量NO 依赖性血管功能的技术。我们假设急性膳食硝酸盐（NO）补充会改善 NO 生物利用度、腿部 FMD 和 PLM 充血。15 名健康的老年男性（69 ± 4 岁）参加了两项实验，以随机、双盲、交叉设计研究的方式，分别饮用 140 毫升浓缩甜菜根汁（800mg NO）或安慰剂（NO 耗尽的甜菜根汁）。在饮用 NO 和安慰剂前后即刻测量血浆亚硝酸盐（NO）和一氧化氮（NO）、血压（BP）、增强指数（AIx75）、脉搏波速度（PWV）、股浅动脉 FMD 和 PLM 充血。安慰剂没有效果，但 NO 导致血浆 NO 增加 8.6 倍，这伴随着 FMD 的增加（NO：+1.18 ± 0.94% vs. 安慰剂：0.23 ± 1.13%， = 0.002），AIx75 降低（NO：-8.7 ± 11.6% vs. 安慰剂：-4.6 ± 5.5%， = 0.027）。在两次试验中，PLM 充血、BP 和 PWV 均无变化。本研究表明，膳食 NO 的剂量可提高 NO 生物利用度，并增强股动脉 FMD 测量的内皮功能。这些发现提供了关于老年人膳食 NO 补充对中央和外周血管反应的具体见解。
