Kassis Amira N, Vanstone Catherine A, AbuMweis Suhad S, Jones Peter J H
School of Dietetics and Human Nutrition, McGill University, Ste-Anne-de-Bellevue, Montréal, Québec, Canada.
Metabolism. 2008 Mar;57(3):339-46. doi: 10.1016/j.metabol.2007.10.008.
Plant sterols (PSs) reduce plasma total and low-density lipoprotein cholesterol (LDL-C) levels by reducing cholesterol absorption; however, it is not known whether the level of dietary cholesterol intake has an impact on the efficacy of PSs on blood lipids. The purpose of this study was to determine the effect of high vs low dietary cholesterol levels on the lipid-lowering efficacy of free PSs. The study was a semirandomized, double-blind, crossover trial consisting of four 28-day feeding phases each separated by a 4-week washout period. Otherwise healthy hypercholesterolemic subjects (n = 22) consumed each of (a) low-cholesterol control (C(-)S(-)), (b) high-cholesterol control (C(+)S(-)), (c) 22 mg PSs per kilogram of body weight with a low-cholesterol diet (C(-)S(+)), and (d) 22 mg PSs per kilogram of body weight with a high-cholesterol diet (C(+)S(+)). Blood was drawn on the first and last 2 days of each phase to measure plasma total cholesterol, LDL-C, high-density lipoprotein cholesterol, and triacylglycerols as well as plasma campesterol and beta-sitosterol concentrations. Dietary cholesterol had no effect on PS efficacy as a cholesterol-lowering agent because no interaction was found between the 2 factors. However, dietary cholesterol and PS intake had significant independent effects on plasma total cholesterol, LDL-C, and high-density lipoprotein cholesterol levels. beta-Sitosterol levels in plasma increased (P < .0001) as a result of PS supplementation. Data from the present study indicate that, although PSs and dietary cholesterol exert independent effects on plasma cholesterol, PS efficacy is not affected by varying levels of cholesterol intake.
植物甾醇（PSs）通过减少胆固醇吸收来降低血浆总胆固醇和低密度脂蛋白胆固醇（LDL-C）水平；然而，尚不清楚膳食胆固醇摄入量是否会影响PSs对血脂的功效。本研究的目的是确定高膳食胆固醇水平与低膳食胆固醇水平对游离PSs降血脂功效的影响。该研究是一项半随机、双盲、交叉试验，包括四个为期28天的喂养阶段，每个阶段之间有4周的洗脱期。其他方面健康的高胆固醇血症受试者（n = 22）分别食用（a）低胆固醇对照饮食（C(-)S(-)）、（b）高胆固醇对照饮食（C(+)S(-)）、（c）每千克体重22毫克PSs加低胆固醇饮食（C(-)S(+)）和（d）每千克体重22毫克PSs加 高胆固醇饮食（C(+)S(+)）。在每个阶段的第1天和最后2天采集血液，以测量血浆总胆固醇、LDL-C、高密度脂蛋白胆固醇和三酰甘油以及血浆菜油甾醇和β-谷甾醇浓度。膳食胆固醇作为一种降胆固醇剂对PSs的功效没有影响，因为未发现这两个因素之间存在相互作用。然而，膳食胆固醇和PSs摄入量对血浆总胆固醇、LDL-C和高密度脂蛋白胆固醇水平有显著的独立影响。补充PSs后，血浆中β-谷甾醇水平升高（P < .0001）。本研究数据表明，虽然PSs和膳食胆固醇对血浆胆固醇有独立影响，但PSs的功效不受胆固醇摄入水平变化的影响。
