College of Health Solutions, Arizona State University, Phoenix, AZ 85004.
College of Health Solutions, Arizona State University, Phoenix, AZ 85004; School of Life Sciences, Arizona State University, Phoenix, AZ 85004.
Nutr Res. 2019 May;65:99-104. doi: 10.1016/j.nutres.2019.02.001. Epub 2019 Feb 22.
Cardiovascular disease risk is elevated in postmenopausal women relative to men of the same age or to younger, premenopausal women. This elevated risk is closely linked to the loss of estrogen, which is a potent stimulator of the vasodilator nitric oxide. While studies have largely supported dietary nitrate supplementation (typically concentrated beetroot juice) to augment plasma nitric oxide, these studies focused mainly on improving vascular fitness of athletes or patient populations. The purpose of this controlled crossover trial was to assess the feasibility of consuming a high-nitrate, leafy green salad twice daily for 10 consecutive days versus a low-nitrate, canned vegetable control (beans, corn, or peas) on plasma nitrate/nitrite concentration and measures of cardiovascular health in postmenopausal women. We hypothesized that plasma nitrate/nitrite concentration and flow-mediated dilation would improve following the leafy green salad treatment. Ten women (52.6 ± 4.9 y; 26.4 ± 6.4 kg/m) completed the two 10-day treatment periods separated by 2-3 weeks washout. The mean fasting plasma nitrate/nitrite concentration was significantly increased following the high-nitrate salad treatment compared to the control (+156% and+ 16% respectively; P = .002, effect size = 0.661). Flow-mediated dilation responded favorably to the high nitrate salad in comparison to the canned vegetable condition (+17% versus -8% respectively; P = .047, effect size = 0.407); however, there were no treatment effects on peripheral or derived central-aortic blood pressure. These data suggest that daily ingestion of nitrate-rich, leafy green salads may prove a useful strategy for improving cardiovascular health in postmenopausal women.
绝经后女性的心血管疾病风险高于同年龄或更年轻的绝经前女性。这种风险的增加与雌激素的丧失密切相关，雌激素是血管舒张因子一氧化氮的有效刺激物。虽然研究主要支持通过饮食补充硝酸盐（通常是浓缩甜菜汁）来增加血浆一氧化氮，但这些研究主要集中在改善运动员或患者群体的血管功能上。本对照交叉试验的目的是评估连续 10 天每天两次食用高硝酸盐叶类绿色沙拉与低硝酸盐罐装蔬菜（豆类、玉米或豌豆）对绝经后妇女血浆硝酸盐/亚硝酸盐浓度和心血管健康的影响。我们假设，在食用叶类绿色沙拉后，血浆硝酸盐/亚硝酸盐浓度和血流介导的扩张会得到改善。10 名女性（52.6±4.9 岁；26.4±6.4kg/m2）完成了两个为期 10 天的治疗期，中间间隔 2-3 周洗脱期。与对照组相比，高硝酸盐沙拉治疗后空腹血浆硝酸盐/亚硝酸盐浓度显著升高（分别增加 156%和 16%；P=0.002，效应大小=0.661）。与罐装蔬菜相比，血流介导的扩张对高硝酸盐沙拉反应良好（分别增加 17%和减少 8%；P=0.047，效应大小=0.407）；然而，两种处理方式对周围或衍生的中心动脉血压均无影响。这些数据表明，每天摄入富含硝酸盐的叶类绿色沙拉可能是改善绝经后女性心血管健康的一种有效策略。
