EFFECT OF LOW-CARBOHYDRATE INTAKE ON CARDIOVASCULAR RISK FACTORS AMONG OBESE ADU

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 心血管疾病(CVD)仍然是全球和美国的主要死亡原因。在过去的几十年里，对饮食中大量营养素(蛋白质、碳水化合物和脂肪)含量的控制已被广泛用于减肥和体重控制。尤其是低碳水化合物饮食，在减肥方面越来越受欢迎。然而，很少有研究考察低碳水化合物饮食对传统的和新的心血管危险因素的长期影响，特别是与当前饮食建议减少脂肪摄入量以降低心血管疾病风险的情况相反。在这项提案中，我们计划进行一项为期12个月的平行随机对照试验，比较低碳水化合物饮食和目前推荐的低脂肪饮食，以减少肥胖成年人的心血管危险因素。这项试验的目的是研究低碳水化合物饮食和低脂肪饮食对肥胖成年人心血管危险因素的长期影响，包括血压(BP)、体重和成分、血脂、血糖、胰岛素、脂肪细胞因子(脂联素、瘦素、抵抗素)和C反应蛋白(CRP)。为了实现这些目标，我们将随机选择130名符合条件的参与者(每组n=65)，分别食用低碳水化合物饮食(40g/d)或低脂肪饮食(7%饱和脂肪，35%总脂肪)。这两种饮食都不会受到能量限制。参与者将在前4周每周与营养师会面，进行一对一咨询，然后在接下来的5个月里每两周在小组会议上见一次营养师，在干预的最后6个月里在更大的小组会议中每月见一次营养师。将在基线、3个月、6个月和12个月收集关于传统和新的心血管疾病风险因素的数据。我们假设，与低脂肪饮食相比，低碳水化合物饮食将降低收缩压和舒张压、体重、体脂百分比、腰围、血清甘油三酯水平以及血浆胰岛素、葡萄糖、瘦素、抵抗素和C反应蛋白水平，并提高血清高密度脂蛋白-胆固醇和脂联素水平。由于心血管疾病是美国和世界范围内最常见的死亡原因，这项研究具有重要的公共卫生意义。它将为低碳水化合物饮食对心血管疾病的传统危险因素以及新的危险因素和炎症因素的潜在长期影响提供新的信息。这项研究的结果将有助于确定与目前推荐的低脂肪饮食相比，低碳水化合物饮食是否可以降低肥胖成年人患心血管疾病的风险。此外，这项试验将为初级研究员Bazzano博士提供一个获得必要的研究技能和经验的机会，以便在研究饮食和生活方式以减少高血压和心血管疾病风险因素的研究中启动成功、可持续和独立的研究生涯。

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. Cardiovascular diseases (CVD) remain the leading cause of death globally as well as here in the United States . Manipulations of the macronutrient (protein, carbohydrate and fat) contents of diet have been used extensively for weight loss and weight control in the past several decades. Low carbohydrate diets, in particular, have gained popularity for weight loss. However, few studies have examined the effects of a diet low in carbohydrates on traditional and novel cardiovascular risk factors in the long term, particularly in contrast to the current dietary recommendations for decreased fat intake to reduce risk of CVD. In this proposal, we plan to conduct a 12-month, parallel-arm, randomized controlled trial of a diet low in carbohydrates versus the currently recommended diet low in fat diet to reduce CVD risk factors among obese adults. The objective of this trial is to examine the long-term effects of a diet low in carbohydrates, as compared to one low in fat, on CVD risk factors, including blood pressure (BP), body weight and composition, serum lipids, plasma glucose, insulin, adipocytokines (adiponectin, leptin, resistin), and C-reactive protein (CRP) among obese adults. In order to accomplish these objectives we will randomize 130 eligible participants (n=65 in each group) to consume either a diet low in carbohydrates (40 g/d) or a diet low in fat (7% saturated fat, 35% total fat). Neither of the diets will be energy-restricted. Participants will meet with a dietitian for one-on-one counseling session weekly for the first 4 weeks, then bi-weekly in small group sessions for the next 5 months, and monthly in larger group sessions for the final 6 months of the intervention. Data on both traditional and novel CVD risk factors will be collected at baseline, 3, 6, and 12 months. We hypothesize that a diet low in carbohydrates as compared to a diet low in fat will lower systolic and diastolic BP, body weight, total percent body fat, waist circumference, serum levels of triglycerides, and plasma levels of insulin, glucose, leptin, resistin, and CRP, and increase serum levels of HDL-cholesterol and adiponectin. Because CVD is the most common cause of death here in the U.S. and world-wide, this study has important public health implications. It will provide new information on the potential long-term effects of diets low in carbohydrates on both the traditional risk factors for CVD as well as novel risk factors and inflammatory factors. The results from this study will help to determine if a diet low in carbohydrates as compared to the currently recommended low fat diet can decrease the risk of CVD among obese adults. In addition, this trial will provide the junior investigator, Dr. Bazzano, an opportunity to acquire research skills and experience necessary to launch a successful, sustainable, and independent research career in the investigation dietary and lifestyle approaches to reduce risk factors for hypertension and CVD.