Dietary carbohydrate & glycemic index effects on oxidation & inflammation

描述(由申请人提供)： 传统的心血管疾病危险因素与动脉粥样硬化风险之间的直接关系已经得到了很好的证实。降低血压和血脂的饮食调整可能为降低风险提供了一个可能的解释。然而，氧化应激，包括氧化低密度脂蛋白(OxLDL)，似乎在动脉粥样硬化的发病机制中是一个重要的步骤，如果不是必须的话，并可能加速这一以炎症为标志的过程(Steinberg，1989)。使用血清和尿液生物标记物测量炎症和氧化应激可以提供对降低心血管风险的机制的洞察，而不仅仅是通过血脂或其他心血管危险因素来预测。在这项应用中，我们建议测量不同类型的饮食模式(高和低血糖指数)和饮食中碳水化合物的数量(高碳水化合物和低碳水化合物)对炎症和氧化应激标志物的影响。这项研究将在Omni-CARB试验(最佳常量营养素和碳水化合物的摄入量)的背景下进行-这是一项随机交叉试验，有160名患有高血压前期或1期高血压的成年人参加，参与者在2008年至2011年期间在约翰霍普金斯大学和哈佛大学参加。申请人是一名合作调查员，此申请得到了首席调查员(哈佛大学弗兰克·萨克斯)的全力支持和批准。OMNI-CARB研究的主要目的是单独和联合研究将碳水化合物从高水平(58%千卡)降低到低水平(43%千卡)和将血糖指数从高水平(血糖指数85)降低到低水平(血糖指数55)对主要已确定的与饮食相关的心血管疾病风险因素和胰岛素敏感性的效果。在这项试验中，对反映氧化应激和炎症的生物标志物的测量是特别相关的结果，因为在固定的大量营养素饮食(碳水化合物、蛋白质和脂肪保持不变)内修改血糖指数预计对血脂和其他传统心血管危险因素(血压)只会产生轻微的影响。我们假设，与摄入等卡路里的“高碳水化合物”饮食和“高血糖指数”饮食相比，食用固定的“低碳水化合物饮食”和“低血糖指数”饮食可以减少氧化应激和炎症。与公共健康相关：在这项应用中，我们建议测量不同类型(高和低血糖指数)的饮食模式和饮食中碳水化合物的数量(高碳水化合物和低碳水化合物)对炎症和氧化应激标志物的影响。这项研究将在Omni-CARB试验(最佳常量营养素和碳水化合物的摄入量)的背景下进行-这是一项随机交叉试验，有160名患有高血压前期或1期高血压的成年人参加，参与者在2008年至2011年期间在约翰霍普金斯大学和哈佛大学参加。我们假设，与摄入等卡路里的“高碳水化合物”饮食和“高血糖指数”饮食相比，食用固定的“低碳水化合物饮食”和“低血糖指数”饮食可以减少氧化应激和炎症。(摘要结束)

DESCRIPTION (provided by applicant): The direct relationship between traditional CVD risk factors and risk of atherosclerosis is well established. Dietary modifications which lower blood pressure and lipids provide a likely explanation for much of the risk reduction. However, oxidative stress, including oxidation of LDL-c (oxLDL) appears to be an important, if not obligatory step in the pathogenesis of atherosclerosis and may accelerate this process which is marked by inflamation (Steinberg, 1989). Measurement of inflammation and oxidative stress using serum and urine biomarkers may offer insight into mechanisms of CVD risk reduction beyond that which is predicted by lipids or other CVD risk factors alone. In this application we propose to measure the effects of dietary patterns that vary the type (high and low glycemic index) and the amount of carbohydrate in the diet (high carbohydrate and low carbohydrate) on markers of inflammation and oxidative stress. This study will be conducted within the setting of the OMNI-CARB trial (Optimal Macronutrient Intake and Carbohydrates)- a randomized cross over trial of 160 adults with prehypertension or stage 1 hypertension enrolling participants between 2008 and 2011 at Johns Hopkins and Harvard. The applicant is a co-investigator and this application has the full support and approval of the Principal Investigator (Frank Sacks, Harvard University). The primary aim of the OMNI-CARB study is to address the efficacy, separate and combined, of reducing carbohydrate from a high level (58% kcal) to a low level (43% kcal) and of lowering the glycemic index from a high level (glycemic index>85) to a low level (glycemic index<55) on the major established diet-related CVD risk factors, as well as insulin sensitivity. Measurement of biomarkers reflective of oxidative stress and inflammation are particularly relevant outcomes in this trial since modifying the glycemic index within a fixed macronutrients diet (carbohydrate, protein and fats held constant) is expected to results in only modest effects on serum lipids and other traditional CVD risk factors (blood pressure). We hypothesize that consumption of a fixed "low carbohydrate diet" and "low glycemic index" diet will decrease oxidative stress and inflammation compared with consumption an isocaloric "high carbohydrate" diet and "high glycemic index" diet. PUBLIC HEALTH RELEVANCE: In this application we propose to measure the effects of dietary patterns that vary the type (high and low glycemic index) and the amount of carbohydrate in the diet (high carbohydrate and low carbohydrate) on markers of inflammation and oxidative stress. This study will be conducted within the setting of the OMNI-CARB trial (Optimal Macronutrient Intake and Carbohydrates)- a randomized cross over trial of 160 adults with prehypertension or stage 1 hypertension enrolling participants between 2008 and 2011 at Johns Hopkins and Harvard. We hypothesize that consumption of a fixed "low carbohydrate diet" and "low glycemic index" diet will decrease oxidative stress and inflammation compared with consumption an isocaloric "high carbohydrate" diet and "high glycemic index" diet. (End of Abstract)