Vanstone Catherine A, Raeini-Sarjaz Mahmoud, Parsons William E, Jones Peter J H
School of Dietetics and Human Nutrition, McGill University, Ste Anne-de-Bellevue, Quebec, Canada.
Am J Clin Nutr. 2002 Dec;76(6):1272-8. doi: 10.1093/ajcn/76.6.1272.
Plant sterols, in various forms, have been shown to reduce total and LDL-cholesterol concentrations. Particularly controversial at present is the effect of the degree of hydrogenation of the plant sterols on cholesterol-lowering efficacy and the responsible mechanisms.
Our goal was to examine the effect of supplementation with unesterified plant sterols and stanols on plasma lipid and phytosterol concentrations and cholesterol absorption, synthesis, and turnover.
Fifteen otherwise healthy hypercholesterolemic subjects consumed each of 4 dietary treatments in a randomized crossover design. Unesterified sterols and stanols were blended into the butter component of the diet at a dosage of 1.8 g/d. The diets contained plant sterols (NS), plant stanols (SS), a 50:50 mixture of sterols and stanols (NSS), or cornstarch (control).
Plasma total cholesterol concentrations were 7.8%, 11.9%, and 13.1% lower (P < 0.01) in the NS, SS, and NSS groups, respectively, than in the control group. LDL-cholesterol concentrations were 11.3%, 13.4%, and 16.0% lower (P < 0.03) in the NS, SS, and NSS groups, respectively, than in the control group. Plasma triacylglycerols and HDL-cholesterol concentrations did not differ significantly across diets. Cholesterol absorption efficiency was 56.0%, 34.4%, and 48.9% lower (P < 0.001) in the NS, SS, and NSS groups, respectively, than in the control group. The fractional synthesis rate was higher by 45.5% (P < 0.003) in the NSS group than in the control group. Plasma campesterol and sitosterol concentrations were higher (P < 0.01) in the NS group and sitosterol concentrations were lower (P < 0.01) in the SS group than in the control group.
These data indicate that, in their free unesterified form, sterols and stanols lower plasma LDL cholesterol equivalently in hypercholesterolemic persons by suppressing cholesterol absorption.
多种形式的植物甾醇已被证明可降低总胆固醇和低密度脂蛋白胆固醇浓度。目前，植物甾醇的氢化程度对降胆固醇功效及相关机制的影响存在特别大的争议。
我们的目标是研究补充未酯化植物甾醇和甾烷醇对血浆脂质和植物甾醇浓度以及胆固醇吸收、合成和周转的影响。
15名其他方面健康的高胆固醇血症受试者采用随机交叉设计，分别食用4种饮食疗法。将未酯化的甾醇和甾烷醇以1.8 g/d的剂量混入饮食的黄油成分中。饮食包括植物甾醇（NS）、植物甾烷醇（SS）、甾醇和甾烷醇的50:50混合物（NSS）或玉米淀粉（对照）。
NS、SS和NSS组的血浆总胆固醇浓度分别比对照组低7.8%、11.9%和13.1%（P<0.01）。NS、SS和NSS组的低密度脂蛋白胆固醇浓度分别比对照组低11.3%、13.4%和16.0%（P<0.03）。不同饮食之间血浆三酰甘油和高密度脂蛋白胆固醇浓度无显著差异。NS、SS和NSS组的胆固醇吸收效率分别比对照组低56.0%、34.4%和48.9%（P<0.001）。NSS组的分数合成率比对照组高45.5%（P<0.003）。NS组的血浆菜油甾醇和谷甾醇浓度高于对照组（P<0.01），SS组的谷甾醇浓度低于对照组（P<0.01）。
这些数据表明，以游离未酯化形式存在的甾醇和甾烷醇通过抑制胆固醇吸收，可同等程度地降低高胆固醇血症患者的血浆低密度脂蛋白胆固醇。
