School of Medicine and Pharmacology, University of Western Australia, Perth, WA, Australia.
Free Radic Biol Med. 2012 Jan 1;52(1):95-102. doi: 10.1016/j.freeradbiomed.2011.09.028. Epub 2011 Oct 1.
Flavonoids and nitrates in fruits and vegetables may protect against cardiovascular disease. Dietary flavonoids and nitrates can augment nitric oxide status via distinct pathways, which may improve endothelial function and lower blood pressure. Recent studies suggest that the combination of flavonoids and nitrates can enhance nitric oxide production in the stomach. Their combined effect in the circulation is unclear. Here, our objective was to investigate the independent and additive effects of flavonoid-rich apples and nitrate-rich spinach on nitric oxide status, endothelial function, and blood pressure. A randomized, controlled, crossover trial with healthy men and women (n=30) was conducted. The acute effects of four energy-matched treatments (control, apple, spinach, and apple+spinach), administered in random order, were compared. Measurements included plasma nitric oxide status, assessed by measuring S-nitrosothiols+other nitrosylated species (RXNO) and nitrite, blood pressure, and endothelial function, measured as flow-mediated dilatation of the brachial artery. Results are means and 95% CI. Relative to control, all treatments resulted in higher RXNO (control, 33 nmol/L, 26, 42; apple, 51 nmol/L, 40, 65; spinach, 86 nmol/L, 68, 110; apple+spinach, 69 nmol/L, 54, 88; P<0.01) and higher nitrite (control, 35 nmol/L, 27, 46; apple, 69 nmol/L, 53, 90; spinach, 99 nmol/L, 76, 129; apple+spinach, 80 nmol/L, 61, 104; P<0.01). Compared to control, all treatments resulted in higher flow-mediated dilatation (P<0.05) and lower pulse pressure (P<0.05), and apple and spinach resulted in lower systolic blood pressure (P<0.05). No significant effect was observed on diastolic blood pressure. The combination of apple and spinach did not result in additive effects on nitric oxide status, endothelial function, or blood pressure. In conclusion, flavonoid-rich apples and nitrate-rich spinach can independently augment nitric oxide status, enhance endothelial function, and lower blood pressure acutely, outcomes that may benefit cardiovascular health.
水果和蔬菜中的类黄酮和硝酸盐可能有助于预防心血管疾病。膳食类黄酮和硝酸盐可以通过不同的途径增加一氧化氮的状态，从而改善内皮功能和降低血压。最近的研究表明，类黄酮和硝酸盐的结合可以增强胃中的一氧化氮生成。它们在循环中的联合作用尚不清楚。在这里，我们的目的是研究富含类黄酮的苹果和富含硝酸盐的菠菜对一氧化氮状态、内皮功能和血压的独立和相加作用。一项随机、对照、交叉试验在健康男性和女性（n=30）中进行。比较了以随机顺序给予的四种能量匹配处理（对照、苹果、菠菜和苹果+菠菜）的急性效应。测量包括通过测量 S-亚硝基硫醇+其他亚硝酰化物质（RXNO）和亚硝酸盐来评估血浆一氧化氮状态、血压和内皮功能，作为肱动脉血流介导的扩张来测量。结果表示为平均值和 95%置信区间。与对照相比，所有处理均导致更高的 RXNO（对照，33nmol/L，26，42；苹果，51nmol/L，40，65；菠菜，86nmol/L，68，110；苹果+菠菜，69nmol/L，54，88；P<0.01）和更高的亚硝酸盐（对照，35nmol/L，27，46；苹果，69nmol/L，53，90；菠菜，99nmol/L，76，129；苹果+菠菜，80nmol/L，61，104；P<0.01）。与对照相比，所有处理均导致更高的血流介导的扩张（P<0.05）和更低的脉压（P<0.05），苹果和菠菜导致更低的收缩压（P<0.05）。舒张压无显著变化。苹果和菠菜的组合对一氧化氮状态、内皮功能或血压没有叠加作用。总之，富含类黄酮的苹果和富含硝酸盐的菠菜可以独立地增加一氧化氮状态、增强内皮功能和降低血压，这些结果可能有益于心血管健康。
