Bond Vernon, Curry Bryan H, Adams Richard G, Millis Richard M, Haddad Georges E
a Department of Health, Human Performance and Leisure Studies and the Cancer Center Physical Medicine and Nutrition Laboratory, Howard University, Washington, DC 20059, USA.
Appl Physiol Nutr Metab. 2014 Feb;39(2):168-72. doi: 10.1139/apnm-2013-0263. Epub 2013 Aug 2.
The advent of medical nutrition therapy and nutritional physiology affords the opportunity to link diet to specific cardiovascular mechanisms, suggesting novel treatments for cardiovascular disease. This study tests the hypothesis that beetroot juice increases the plasma nitric oxide (NO) concentration, which is associated with improvements in cardiorespiratory function at rest and during submaximal aerobic exercise. The subjects were 12 healthy, young adult, normotensive African-American females, with a body mass of 61 ± 2 kg, body fat of 28% ± 4%, and peak oxygen consumption of 26 ± 3 mL·kg(-1)·min(-1). The subjects were studied at rest and during cycle ergometer exercise at 40%, 60%, and 80% of peak oxygen consumption. Plasma NO concentration, respiratory quotient (RQ), minute ventilation, systolic and diastolic blood pressure (SBP and DBP), heart rate, and oxygen consumption were compared between isocaloric, isovolumetric placebo control orange juice and experimental beetroot juice treatments on separate days. The beetroot juice treatment increased plasma NO concentration and decreased oxygen consumption, SBP, and the heart rate-SBP product at rest and at 40%, 60%, and 80% of peak oxygen consumption in the absence of significant effects on RQ, minute ventilation, heart rate, and DBP. These findings suggest that, in healthy subjects, beetroot juice treatments increase plasma NO concentration and decrease cardiac afterload and myocardial oxygen demand at rest and during 3 submaximal levels of aerobic exercise. Future studies should determine the cellular and molecular mechanisms responsible for the improvement in cardiorespiratory function associated with dietary nitrate supplementation and whether they translate into better cardiovascular function and exercise tolerance in individuals with a compromised cardiovascular system.
医学营养疗法和营养生理学的出现为将饮食与特定心血管机制联系起来提供了契机，这意味着可能有针对心血管疾病的新疗法。本研究检验了以下假设：甜菜根汁可提高血浆一氧化氮（NO）浓度，这与静息和次最大强度有氧运动时心肺功能的改善有关。研究对象为12名健康、年轻的成年、血压正常的非裔美国女性，体重61±2千克，体脂28%±4%，峰值耗氧量26±3毫升·千克-1·分钟-1。研究对象在静息状态以及在峰值耗氧量的40%、60%和80%的功率自行车运动期间接受研究。在不同日期，对等热量、等容积的安慰剂对照橙汁和实验性甜菜根汁处理组之间的血浆NO浓度、呼吸商（RQ）、分钟通气量、收缩压和舒张压（SBP和DBP）、心率及耗氧量进行了比较。甜菜根汁处理可提高血浆NO浓度，并在静息状态以及峰值耗氧量的40%、60%和80%时降低耗氧量、SBP及心率-收缩压乘积，而对RQ、分钟通气量、心率和DBP无显著影响。这些发现表明，在健康受试者中，甜菜根汁处理可提高血浆NO浓度，并在静息和3个次最大强度有氧运动水平期间降低心脏后负荷和心肌需氧量。未来的研究应确定与膳食硝酸盐补充相关的心肺功能改善的细胞和分子机制，以及这些机制是否能转化为心血管系统受损个体更好的心血管功能和运动耐力。
