Vega G L, Groszek E, Wolf R, Grundy S M
J Lipid Res. 1982 Aug;23(6):811-22.
The mechanisms of the hypocholesterolemic effect of polyunsaturated fats (PUSF) are not well understood. One possibility is that these fats uniquely reduce the cholesterol content of lipoproteins. The present study was carried out to determine specifically whether the ratio of cholesterol-to-protein (or apoB) in LDL (or other lipoproteins) is reduced by PUSF; also, lipoprotein composition was examined for other possible changes. Eight men and two women with different levels of plasma cholesterol were studied on the metabolic ward for 8 weeks. They were given a diet high in saturated fats (SF) for 4 weeks and another rich in PUSF for 4 weeks. On PUSF diets, mean plasma cholesterol decreased by 25% (SF = 296 +/- 27 (SEM) vs. PUSF = 223 +/- 21 mg/dl) as did total plasma apoB (155 +/- 8 vs. 116 +/- 13 mg/dl). LDL-Cholesterol decreased by 26%, and LDL-apoB fell by 29%. The mean ratio of cholesterol-to-apoB did not change significantly (SF = 1.52 +/- 0.04 vs. PUSF = 1.48 +/- 0.07). Likewise, HDL-cholesterol decreased by 15% (SF = 51 +/- 5 vs. PUSF = 43 +/- 4 mg/dl), and total plasma apoA-I was reduced by 19% (95 +/- 15 vs. 77 +/- 6 mg/dl); also, no change in the cholesterol-to-apoA-I in HDL was noted. Finally, there were no changes in cholesterol/apoB or triglyceride/apoB ratios in VLDL despite a 23% decrease in plasma triglycerides on PUSF. Thus, the hypocholesterolemic effect of PUSF was uniform for all lipoproteins and usually was accompanied by a corresponding decrease in concentrations of apoprotein constituents.
多不饱和脂肪（PUSF）降胆固醇作用的机制尚未完全明确。一种可能性是这些脂肪能独特地降低脂蛋白中的胆固醇含量。本研究旨在具体确定PUSF是否会降低低密度脂蛋白（LDL，或其他脂蛋白）中胆固醇与蛋白质（或载脂蛋白B）的比例；同时，还检查了脂蛋白组成是否有其他可能的变化。8名男性和2名女性，血浆胆固醇水平各异，在代谢病房接受了为期8周的研究。他们先食用富含饱和脂肪（SF）的饮食4周，然后再食用富含PUSF的饮食4周。在食用PUSF饮食时，平均血浆胆固醇下降了25%（SF = 296 ± 27（标准误）mg/dl，PUSF = 223 ± 21 mg/dl），血浆总载脂蛋白B也下降了（155 ± 8 mg/dl vs. 116 ± 13 mg/dl）。低密度脂蛋白胆固醇下降了26%，低密度脂蛋白载脂蛋白B下降了29%。胆固醇与载脂蛋白B的平均比例没有显著变化（SF = 1.52 ± 0.04，PUSF = 1.48 ± 0.07）。同样，高密度脂蛋白胆固醇下降了15%（SF = 51 ± 5 mg/dl，PUSF = 43 ± 4 mg/dl），血浆总载脂蛋白A-I下降了19%（95 ± 15 mg/dl vs. 77 ± 6 mg/dl）；此外，高密度脂蛋白中胆固醇与载脂蛋白A-I的比例没有变化。最后，尽管食用PUSF时血浆甘油三酯下降了23%，但极低密度脂蛋白中胆固醇/载脂蛋白B或甘油三酯/载脂蛋白B的比例没有变化。因此，PUSF对所有脂蛋白的降胆固醇作用是一致的，并且通常伴随着载脂蛋白成分浓度的相应降低。
