van Raaij J M, Katan M B, Hautvast J G, Hermus R J
Am J Clin Nutr. 1981 Jul;34(7):1261-71. doi: 10.1093/ajcn/34.7.1261.
The effects of casein and soy protein on serum cholesterol levels and lipoprotein composition were studied in 69 healthy volunteers (18 to 28 yr of age) under strict dietary control. Subjects were fed for 6 wk on diets containing 13% of energy as protein, 38% as fat (P/S ratio = 0.6) and about 380 mg cholesterol per day. Of the protein in the diets 65% consisted of casein or soy protein or a 2:1 mixture of casein and soy protein. After a control period of 10 days during which all the subjects received the casein-soy diet, 20 subjects continued on this diet for the next 4 wk as a base-line control, 25 subjects switched to the casein diet, and the remaining 24 subjects switched to the soy diet. Both food records and chemical analysis of double portions revealed that the diets were completely identical except for the type of protein. Average serum cholesterol levels at the end of the control period were 152 +/- 27 mg/dl (3.93 +/- 0.69 mmol/l) and 153 +/- 23 mg/dl (3.95 +/- 0.60 mmol/l) (mean +/- SD) for the casein and soy group, respectively. At the end of the test period the levels were 149 +/- 24 and 150 +/- 23 mg/dl, respectively; thus there was no significant change on either diet. On the casein diet there was no change in the low-density lipoprotein cholesterol concentration, and only a slight, nonsignificant increase in the high-density lipoprotein cholesterol concentration. On the soy diet, however, there was a significant decline in low-density lipoprotein-cholesterol (-6.6 mg/dl; -0.17 mmol/l) and a significant increase in high-density lipoprotein-cholesterol (+5.8 mg/dl; +0.15 mmol/l). The decline in low-density lipoprotein cholesterol in the soy group was significantly different from the small change in the casein group, but the difference in increase in high-density lipoprotein cholesterol in the soy and the casein group was only weakly significant. This suggest that soy protein could have a slight beneficial effect on the distribution of cholesterol over the various lipoprotein fractions, even at constant total cholesterol concentration.
在严格的饮食控制下，对69名健康志愿者（18至28岁）研究了酪蛋白和大豆蛋白对血清胆固醇水平及脂蛋白组成的影响。受试者食用了6周的饮食，其中蛋白质提供13%的能量，脂肪提供38%的能量（P/S比值 = 0.6），每天约含380毫克胆固醇。饮食中的蛋白质65%由酪蛋白或大豆蛋白或酪蛋白与大豆蛋白2:1的混合物组成。在10天的对照期内，所有受试者都食用酪蛋白 - 大豆饮食，之后，20名受试者继续食用这种饮食4周作为基线对照，25名受试者转而食用酪蛋白饮食，其余24名受试者转而食用大豆饮食。食物记录和双份食物的化学分析均显示，除蛋白质类型外，这些饮食完全相同。酪蛋白组和大豆组在对照期末的平均血清胆固醇水平分别为152±27毫克/分升（3.93±0.69毫摩尔/升）和153±23毫克/分升（3.95±0.60毫摩尔/升）（均值±标准差）。在试验期末，水平分别为149±24和150±23毫克/分升；因此，两种饮食均无显著变化。食用酪蛋白饮食时，低密度脂蛋白胆固醇浓度没有变化，高密度脂蛋白胆固醇浓度仅有轻微的、不显著的升高。然而，食用大豆饮食时，低密度脂蛋白胆固醇显著下降（-6.6毫克/分升；-0.17毫摩尔/升），高密度脂蛋白胆固醇显著升高（+5.8毫克/分升；+0.15毫摩尔/升）。大豆组低密度脂蛋白胆固醇的下降与酪蛋白组的微小变化有显著差异，但大豆组和酪蛋白组高密度脂蛋白胆固醇升高的差异仅为微弱显著。这表明，即使在总胆固醇浓度恒定的情况下，大豆蛋白对胆固醇在各种脂蛋白组分中的分布可能有轻微的有益作用。
