LATITUDE WITHIN AN NCEP STEP I DIET--AN OPTIMAL DIET

该研究的目的是检查是否由于过分强调避免脂肪和胆固醇而不重视植物性食物，NCEP/AHA第一步饮食对降低冠心病（CHD）风险的潜在公共卫生影响目前可能被低估。植物性食物中的大量饮食因素与减少各种冠心病风险因素有关。然而，在过去的十年里，食品工业生产了成千上万种新的“减脂”食品，这使得人们有可能遵循以低脂商业食品（通常热量高）而不是植物性食品为基础的第一步饮食。我们将设计两种符合NCEP/AHA第一步饮食指南的饮食，并在总脂肪、饱和脂肪、单不饱和脂肪、多不饱和脂肪、胆固醇、蛋白质和总碳水化合物方面进行匹配。一种饮食将包括大部分植物性食物，并且植物蛋白、精氨酸复合碳水化合物、可溶性和不可溶性纤维、维生素E、C和叶酸、类胡萝卜素、植物甾醇、植物雌激素、类黄酮、大蒜素和皂苷（NCEP-Plus）的含量相对较高。另一种饮食将包括大量市售的低脂产品，动物蛋白、简单碳水化合物和反式脂肪酸的含量相对较高（NCEP-Low）。在一项采用平行设计的临床试验中，100名ldl -胆固醇中度升高（LDL-C 130-190 mg/dL）的成年人将被随机分配到两种饮食中的一种，为期四周。所有的饭菜都将提供。两种研究饮食的组成将通过化学分析来确定。主要研究终点将包括空腹血清LDL-C、胰岛素和同型半胱氨酸水平、单核细胞粘附和内皮功能。我们的目的是研究关注避免脂肪和胆固醇而不包括植物性食物是否会导致低估NCEP/AHA第一步饮食的潜在健康益处，并确定通过使用当前的营养知识来设计“最佳”整体饮食，可以实现的整体冠心病风险因素有利变化的程度。

The objective of the study is to examine whether the potential public health impact on coronary heart disease (CHD) risk reduction of an NCEP/AHA Step One Diet may currently be underestimated because of an overemphasis on the avoidance of fat and cholesterol and an underemphasis on the inclusion of plant-based foods. A large number of dietary factors in plant based foods have been linked to the reduction of various CHD risk factors. However, the food industry's production of thousands of new "reduced-fat" food products over the last decade has now made it possible to follow a Step One Diet with a foundation in low-fat commercial foods (that are often high in calories) rather than plant-based foods. We will design two diets that both meet NCEP/AHA Step One Diet guidelines and are matched on total fat, saturated fat, monounsaturated fat, polyunsaturated fat, cholesterol, protein and total carboyhydrate. One diet will include a large proportion of plant- based foods, and will be relatively higher in content of plant protein, arginine complex carbohydrates, soluble and insoluble fiber, Vitamins E, C and folate, carotenoids,phytosterols, phytoestrogens, flavonoids, allicin and saponins (NCEP-Plus). The other diet will include a large proportion of commercially available reduced-fat products and will be relatively higher in animal protein, simple carbohydrates and trans fatty acids (NCEP-Low). In a clinical trial using a parallel design, 100 adults with moderately elevated LDL-cholesterol (LDL-C 130-190 mg/dL) will be randomized to one of the two diets for four weeks. All meals will be provided. The composition of the two study diets will be determined by chemical analysis. The primary study endpoints will include fasting serum levels of LDL-C, insulin and homocysteine, monocyte adhesion, and endothelial function. Our intentions are to examine whether a focus on avoiding fat and cholesterol rather than including plant-based food result in underestimating the potential health benefits of an NCEP/AHA Step One Diet, and to determine the magnitude of favorable changes in an overall CHD risk factor profile that can be achieved by using current nutrition knowledge to design an "optimal" overall diet.