PLANT STANOL ESTERS ON USUAL DIET VS NCEP STEP 1 DIET ON LIPIDS & LIP

植物甾醇是天然存在的C5-C6键饱和的植物甾醇。因此，虽然谷甾醇在这个位置有一个双键，但谷甾醇有一个单键。谷甾醇几乎完全不能被肠道吸收，也会减少胆固醇的吸收。谷甾醇的降胆固醇作用通过转化为脂肪酸酯而增强。在芬兰高胆固醇血症患者的研究中，植物甾醇酯（PSE）显示总胆固醇（TC）和低密度脂蛋白胆固醇（LDL-C）分别降低6 - 11%和9 - 14%。芬兰研究对象的饮食在总脂肪、饱和脂肪和胆固醇方面都高于典型的美国饮食。确定总脂肪和饱和脂肪含量较低的饮食、第一步饮食和PSE一起降低LDL-C的效果是否超过单独治疗的效果是很重要的。这项为期6周的随机对照研究的目的是：1)确定四个治疗组（常规饮食、常规饮食+ PSE、步骤一饮食、步骤一饮食+ PSE）之间是否存在差异；2)量化极低密度脂蛋白（VLDL）、LDL-C、高密度脂蛋白（HDL）的脂蛋白组成可能发生的变化，以及将PSE纳入常规饮食或步骤一饮食的受试者的适当亚组分；3)确定脂质和脂蛋白水平变化的时间依赖性。

Phytosterols are naturally occurring plant sterols in which the C5-C6 bond is saturated. Thus, while sitostanol bears a double bond at this position, sitostanol has a single bond. Sitostanol is almost completely unabsorbable by the intestine and also reduces the absorption of cholesterol. The cholesterol-lowering effect of sitostanol is increased by converting it to fatty acid esters. In studies conducted in Finnish hypercholesterolemic subjects, plant stanol esters (PSE) have shown decreases in total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) of 6 to 11% and 9 to 14%, respectively. The diet of Finnish research subjects was higher in total fat, saturated fat, and cholesterol than the typical American diet. It is important to determine if a diet lower in total and saturated fat, the Step I Diet, and PSE together will result in LDL-C lowering that exceeds either treatment alone. The purpose of this randomized controlled 6-week study is to: 1) determine if there are differences among four treatment groups (usual diet, usual diet + PSE, Step I Diet, Step I Diet + PSE), 2) to quantify changes that may occur in lipoprotein composition of very low density lipoprotein (VLDL), LDL-C, high density lipoprotein (HDL), and appropriate subfractions of subjects incorporating PSE into their usual diets or the Step I Diet, and 3) to determine the time dependence of changes in level of lipids and lipoproteins.