EFFECT OF GLYCEMIC INDEX AND CEREAL FIBER ON VASCULAR ENDOTHELIAL FUNCTION

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 研究中心，而研究中心不一定是研究者所在的机构。 使用高分辨率超声对肱动脉进行血流介导的扩张（FMD）是一种公认的用于人体内内皮产生的一氧化氮（NO）的无创生物测定法。 NO已被表征为有效的血管扩张剂，但NO在维持健康内皮和抑制动脉粥样硬化的发展、进展和临床表现的关键步骤中也具有相当大的作用。 餐后状态可能是动脉粥样硬化发展的关键。 谷物纤维含量高的饮食与降低心血管疾病的风险有关。 相反，高血糖指数（GI）饮食与心血管死亡率增加有关。 我们假设谷物纤维对FMD的有益作用强于GI的潜在不利影响。 因此，我们假设早餐富含谷物纤维将显著改善FMD，而不考虑GI。 相比之下，我们假设高GI早餐低谷物纤维会损害FMD。 我们还假设，低GI和谷物纤维的早餐对餐后FMD没有影响。 在18-64岁的健康成人中，将使用高分辨率超声和边缘检测软件在四种早餐[（1）高纤维，低GI;（2）高纤维，高GI;（3）低纤维，低GI;（4）低纤维，高GI]之前和之后2小时和4小时评估肱动脉血流介导的扩张（FMD）。 重复测量的方差分析将用于评估FMD对膳食挑战的反应差异。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Flow-mediated dilation (FMD) of the brachial artery using high-resolution ultrasound is a well accepted non-invasive bioassay for in vivo endothelium-generated nitric oxide (NO) in humans. NO has been characterized as a potent vasodilator, but NO also has a considerable role in maintaining healthy endothelium and inhibiting key steps in the development, progression, and clinical manifestations of atherosclerosis. The postprandial state may be critical in the development of atherosclerosis. Diets high in cereal fiber have been linked to reduced risk of cardiovascular disease. Conversely, high-glycemic index (GI) diets have been linked to increased cardiovascular mortality. We postulate that the beneficial effect of cereal fiber on FMD is stronger than the potentially adverse effect of GI. Therefore, we hypothesize that breakfast meals high in cereal fiber will acutely improve FMD, regardless of GI. By contrast, we hypothesize that a high-GI breakfast meal that is low in cereal fiber will impair FMD. We also hypothesize that a breakfast meal that is low in both GI and cereal fiber will have no effect on postprandial FMD. Brachial artery flow-mediated dilation (FMD) will be assessed before and at 2 h and 4 h after each of four breakfast meals [(1) High-fiber, Low GI; (2) High-fiber, High-GI; (3) Low-fiber, Low-GI; (4) Low-fiber, High-GI] using high-resolution ultrasound and edge-detection software in healthy adults ages 18-64. Analysis of variance with repeated measures will be used to assess differences in FMD in response to the meal challenges.