Adverse metabolic effects of dietary sugar _ Ad libitum vs energy-balanced diets

9.项目摘要： 最近的研究表明，食用高果糖玉米糖浆（HFCS）或蔗糖甜 与等热量饮料相比，饮料增加了健康成人CVD的脂质/脂蛋白风险因素 葡萄糖或低脂牛奶这些研究中最长的一项，采用了6个月的干预，也表明 肝脏和肌肉TG增加，内脏脂肪沉积增加。这些研究都没有发现 与对照组相比，食用HFCS/蔗糖饮料的受试者之间的体重增加差异 饮料.这些结果表明，不仅仅是多余的卡路里和体重增加介导了 饮食中的糖/果糖对代谢疾病的发展;相反，饮食中的糖本身也是 贡献者。然而，目前尚不清楚食用过量的糖是否会增加风险 在没有积极的能量平衡和体重增加的情况下，代谢疾病的因素，也不是 糖消耗的不利影响因体重增加而加剧。这项研究将测试整体 假设食用含HFCs的饮料会增加代谢疾病的风险因素，甚至 当与能量平衡的饮食一起食用时，可以防止体重增加，并且风险因素增加， 在能量正平衡的环境中饮用含氢氟碳化合物的饮料， 导致体重增加。我们还将测试假设，即在盲法、受控饮食条件下， HFCs甜味饮料的消费将增加能量摄入和体重增加超过 饮用含糖精的饮料。我们将衡量与以下方面相关的风险因素和过程： 3组年轻健康成人的代谢疾病，他们将消耗1）25%的能量需求， HFCs-甜饮料与能量平衡的饮食; 2）25%的能量需求作为HFCs- 加糖饮料与随意饮食;或3）加糖饮料与随意饮食， 8周所有的饮食，制定达到可比的常量营养素摄入量（55%的能量作为碳水化合物， 35%脂肪，15%蛋白质），将在整个研究期间提供给受试者。 study.我们假设，在能量平衡的饮食中， 导致不良的代谢作用，尽管没有体重增加。HFCS-sweeted的消费量 自由饮食的饮料将导致增加的能量摄入和体重增加， 它也会对新陈代谢产生不良影响， 在能量平衡的饮食中饮用含氢氟碳化合物的饮料。这些结果将 研究表明，饮用含HFCs的饮料会增加患代谢性疾病的风险， 直接，通过果糖对脂质和碳水化合物代谢的不利影响，间接，通过影响 HFCs加糖饮料，以促进过量的能量摄入和体重增加。这些发现将 有可能影响饮食指南和公共卫生政策。

9. Project Summary: Recent studies have demonstrated that consuming high fructose corn syrup (HFCS)- or sucrose-sweetened beverages increased lipid/lipoprotein risk factors for CVD in healthy adults compared with iso-caloric amounts of glucose or low-fat milk. The longest of these studies, which utilized a 6-month intervention, also showed increased liver and muscle TG and increased visceral adipose deposition. Neither of these studies found differences in weight gain between subjects consuming HFCS/sucrose beverages compared with control beverages. These results suggest that it is not just excess calories and weight gain that mediate the effects of dietary sugar/fructose on the development of metabolic disease; rather, dietary sugar per se is also a contributor. However, it is not known whether consumption of excessive amounts of sugar can increase risk factors for metabolic disease in the absence of positive energy balance and weight gain, nor whether the adverse effects of sugar consumption are exacerbated by weight gain. This study will test the overall hypotheses that consumption of HFCS-sweetened beverages increases risk factors for metabolic disease even when consumed with an energy-balanced diet that prevents weight gain, and that risk factors are increased to a greater extent when HFCS-sweetened beverages are consumed in a setting of positive energy balance that results in weight gain. We will also test the hypothesis, that under blinded, controlled, dietary conditions, consumption of HFCS-sweetened beverages will increase energy intake and body weight gain more than consumption of aspartame-sweetened beverages. We will measure risk factors and processes associated with metabolic disease in 3 groups of young, healthy adults who will consume 1) 25% of energy requirement as HFCS-sweetened beverages with an energy-balanced diet; 2) 25% of energy requirement as HFCS- sweetened beverages with an ad libitum diet; or 3) aspartame-sweetened beverages with an ad libitum diet for 8 weeks. All diets, formulated to achieve a comparable macronutrient intake (55% energy as carbohydrate, 35% fat, 15% protein) among all 3 experimental groups, will be provided to the subjects throughout the entire study. We hypothesize that consumption of HFCS-sweetened beverages with the energy-balanced diet will result in adverse metabolic effects, despite the absence of weight gain. Consumption of HFCS-sweetened beverages with the ad libitum diet will result in increased energy intake and body weight gain compared with aspartame-sweetened beverages, and will also result in adverse metabolic effects that are more marked than with consumption of HFCS-sweetened beverages with the energy-balanced diet. These results will demonstrate that consumption of HFCS-sweetened beverages increases risk for metabolic disease both directly, via the adverse effects of fructose on lipid and carbohydrate metabolism, and indirectly, via the effects of HFCS-sweetened beverages to promote excess energy intake and body weight gain. These findings will have the potential to influence dietary guidelines and public health policy.