Lindsey S, Benattar J, Pronczuk A, Hayes K C
Foster Biomedical Research Laboratory, Brandeis University, Waltham, Massachusetts 02254.
Proc Soc Exp Biol Med. 1990 Nov;195(2):261-9. doi: 10.3181/00379727-195-43145.
In order to examine the qualitative effect of different fats and specific fatty acids on plasma lipids and lipoprotein metabolism, six low fat, cholesterol-free diets were fed to young male hamsters (10/group) for a 4-week period. Fat blends were formulated with coconut oil, palm oil, soybean oil, high oleic acid safflower oil, butter, corn oil, and canola oil. Diets contained 13% energy as fat and dietary polyunsaturate/saturate ratios ranged from 0.12 to 1.04, one of which incorporated the American Heart Association-recommended concentrations of saturates, monoenes, and polyenes and another reflected the current American Fat Blend. In three diets the polyunsaturate/monounsaturate/saturate ratio was held constant while only the 12:0, 14:0, and 16:0 were varied. Plasma lipoproteins and apoproteins were assessed in conjunction with the abundance of specific hepatic and intestinal mRNA for the low density lipoproteins (LDL) receptor and various apolipoproteins associated with cholesterol metabolism. The plasma cholesterol response was lowest with the American Heart Association blend and equally elevated by the more saturated, low polyene diets (polyunsaturate/saturate, 0.12-0.38). Replacing 12:0 plus 14:0 from coconut oil with 16:0 as palm oil induced a significant increase in high density lipoprotein (HDL) cholesterol with a trend toward decreased LDL. These shifts in lipoprotein cholesterol were corroborated by measures of the LDL/HDL ratio, the plasma apolipoprotein B/apolipoprotein A1 ratio, and differences in the synthesis of apolipoproteins and the LDL receptor based on estimates of the mRNA for these proteins in the liver and gut, using specific cDNA probes for apolipoprotein A1, apolipoprotein B, apolipoprotein E, and the LDL receptor. Although it has been suggested that dietary polyenes lower total plasma cholesterol, including HDL, and that saturated fat increases both these pools of cholesterol, the current data represents the first evidence that a specific saturated fatty acid, i.e., palmitic acid, may enhance HDL production.
为了研究不同脂肪和特定脂肪酸对血浆脂质及脂蛋白代谢的定性影响，给年轻雄性仓鼠（每组10只）喂食六种低脂、无胆固醇饮食，为期4周。脂肪混合物由椰子油、棕榈油、大豆油、高油酸红花油、黄油、玉米油和菜籽油配制而成。饮食中脂肪提供13%的能量，膳食多不饱和脂肪酸/饱和脂肪酸比例在0.12至1.04之间，其中一种饮食采用了美国心脏协会推荐的饱和脂肪酸、单不饱和脂肪酸和多不饱和脂肪酸浓度，另一种反映了当前美国的脂肪混合物。在三种饮食中，多不饱和脂肪酸/单不饱和脂肪酸/饱和脂肪酸比例保持恒定，仅改变12:0、14:0和16:0的含量。结合肝脏和肠道中低密度脂蛋白（LDL）受体及与胆固醇代谢相关的各种载脂蛋白的特定mRNA丰度，评估血浆脂蛋白和载脂蛋白。美国心脏协会的混合物使血浆胆固醇反应最低，而饱和度更高、多不饱和脂肪酸含量低的饮食（多不饱和脂肪酸/饱和脂肪酸，0.12 - 0.38）使血浆胆固醇反应同样升高。用棕榈油中的16:0替代椰子油中的12:0加14:0可使高密度脂蛋白（HDL）胆固醇显著增加，同时低密度脂蛋白有降低趋势。通过测量LDL/HDL比例、血浆载脂蛋白B/载脂蛋白A1比例，以及使用载脂蛋白A1、载脂蛋白B、载脂蛋白E和LDL受体的特异性cDNA探针，基于肝脏和肠道中这些蛋白质的mRNA估计值来评估载脂蛋白和LDL受体合成的差异，证实了脂蛋白胆固醇的这些变化。尽管有人提出膳食多不饱和脂肪酸会降低包括HDL在内的总血浆胆固醇，而饱和脂肪会增加这两个胆固醇池，但目前的数据首次证明一种特定的饱和脂肪酸，即棕榈酸，可能会促进HDL的产生。
