Lichtenstein A H
Lipid Metabolism Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA.
J Cardiopulm Rehabil. 2000 May-Jun;20(3):143-6. doi: 10.1097/00008483-200005000-00001.
Trans fatty acids are unsaturated fatty acids that contain at least one double bond in the trans configuration. In the diet they occur at relatively low levels in meat and dairy products as a by-product of fermentation in ruminant animals or in hydrogenated fats as a consequence of the hydrogenation process. In general, dietary hydrogenated fat/trans fatty acids have been reported to increase LDL cholesterol levels relative to oil in the natural state or cis fatty acids. In contrast, dietary hydrogenated fat/trans fatty acids have been reported have to have little effect or decrease HDL cholesterol levels, the later observation restricted to relatively high intakes of trans fatty acids. These two effects result in higher, therefore less favorable, total or LDL cholesterol/HDL cholesterol ratios. Significant increases in Lp(a) levels have been reported after consumption of diets relatively high in trans fatty acids compared with either unsaturated or saturated fatty acids. However, the magnitude of the change is for the most part small and the physiological significance of this observation has yet to be resolved. Data related to the mechanism by which hydrogenated fat/trans fatty acids alter serum lipid levels and other risk factors for cardiovascular disease are in the nascent stages. At this time it would appear prudent that public health recommendations should be aimed at encouraging the moderate consumption of products low in saturated fat or minimally hydrogenated. Trans fatty acids intake should not be stressed at the expense of saturated fat but should augment it.
反式脂肪酸是指含有至少一个反式构型双键的不饱和脂肪酸。在饮食中，它们在肉类和奶制品中含量相对较低，是反刍动物发酵的副产品，或者是氢化过程中氢化脂肪的产物。一般来说，据报道，与天然状态的油脂或顺式脂肪酸相比，饮食中的氢化脂肪/反式脂肪酸会使低密度脂蛋白胆固醇水平升高。相比之下，据报道，饮食中的氢化脂肪/反式脂肪酸对高密度脂蛋白胆固醇水平影响很小或会使其降低，后一种观察结果仅限于反式脂肪酸摄入量相对较高的情况。这两种作用导致总胆固醇或低密度脂蛋白胆固醇/高密度脂蛋白胆固醇的比值升高，因而更不理想。与食用不饱和脂肪酸或饱和脂肪酸的饮食相比，食用反式脂肪酸含量相对较高的饮食后，脂蛋白(a)水平会显著升高。然而，这种变化的幅度在很大程度上较小，这一观察结果的生理意义尚未得到解决。与氢化脂肪/反式脂肪酸改变血脂水平及心血管疾病其他危险因素的机制相关的数据尚处于初期阶段。目前看来，审慎的公共卫生建议应旨在鼓励适度食用饱和脂肪含量低或氢化程度最低的产品。不应以牺牲饱和脂肪为代价来强调反式脂肪酸的摄入量，而应增加饱和脂肪的摄入量。
