University of L'Aquila, Department of Internal Medicine and Public Health, Viale S Salvatore, Delta 6 Medicina, 67100 Coppito, L'Aquila, Italy.
Hypertension. 2012 Sep;60(3):827-32. doi: 10.1161/HYPERTENSIONAHA.112.193995. Epub 2012 Jul 30.
Nitric oxide plays a pivotal role in regulating vascular tone. Different studies show endothelial function is impaired during hyperglycemia. Dark chocolate increases flow-mediated dilation in healthy and hypertensive subjects with and without glucose intolerance; however, the effect of pretreatment with dark chocolate on endothelial function and other vascular responses to hyperglycemia has not been examined. Therefore, we aimed to investigate the effects of flavanol-rich dark chocolate administration on (1) flow-mediated dilation and wave reflections; (2) blood pressure, endothelin-1 and oxidative stress, before and after oral glucose tolerance test (OGTT). Twelve healthy volunteers (5 males, 28.2±2.7 years) randomly received either 100 g/d dark chocolate or flavanol-free white chocolate for 3 days. After 7 days washout period, volunteers were switched to the other treatment. Flow-mediated dilation, stiffness index, reflection index, peak-to-peak time, blood pressure, endothelin-1 and 8-iso-PGF(2α) were evaluated after each treatment phase and OGTT. Compared with white chocolate, dark chocolate ingestion improved flow-mediated dilation (P=0.03), wave reflections, endothelin-1 and 8-iso-PGF(2α) (P<0.05). After white chocolate ingestion, flow-mediated dilation was reduced after OGTT from 7.88±0.68 to 6.07±0.76 (P=0.027), 6.74±0.51 (P=0.046) at 1 and 2 h after the glucose load, respectively. Similarly, after white chocolate but not after dark chocolate, wave reflections, blood pressure, and endothelin-1 and 8-iso-PGF(2α) increased after OGTT. OGTT causes acute, transient impairment of endothelial function and oxidative stress, which is attenuated by flavanol-rich dark chocolate. These results suggest cocoa flavanols may contribute to vascular health by reducing the postprandial impairment of arterial function associated with the pathogenesis of atherosclerosis.
一氧化氮在调节血管张力方面起着关键作用。不同的研究表明，高血糖会损害内皮功能。黑巧克力可增加健康人群和高血压人群以及葡萄糖耐量正常和异常人群的血流介导的扩张；然而，黑巧克力预处理对内皮功能和其他血管对高血糖反应的影响尚未被检测到。因此，我们旨在研究富含黄烷醇的黑巧克力给药对（1）血流介导的扩张和波反射；（2）口服葡萄糖耐量试验（OGTT）前后的血压、内皮素-1 和氧化应激的影响。12 名健康志愿者（5 名男性，28.2±2.7 岁）随机接受 100g/d 黑巧克力或无黄烷醇白巧克力 3 天。在 7 天洗脱期后，志愿者切换到另一种治疗方法。在每个治疗阶段和 OGTT 后评估血流介导的扩张、僵硬指数、反射指数、峰峰值时间、血压、内皮素-1 和 8-异前列腺素 F2α。与白巧克力相比，黑巧克力摄入可改善血流介导的扩张（P=0.03）、波反射、内皮素-1 和 8-异前列腺素 F2α（P<0.05）。在白巧克力摄入后，OGTT 使血流介导的扩张从 7.88±0.68 降低至 6.07±0.76（P=0.027），在葡萄糖负荷后 1 和 2 小时分别为 6.74±0.51（P=0.046）。同样，在白巧克力但不在黑巧克力后，波反射、血压以及内皮素-1 和 8-异前列腺素 F2α 在 OGTT 后增加。OGTT 导致内皮功能和氧化应激的急性、短暂损害，而富含黄烷醇的黑巧克力可减轻这种损害。这些结果表明，可可黄烷醇可通过减少与动脉粥样硬化发病机制相关的餐后动脉功能损害，从而有助于血管健康。
