Hudgins L C, Seidman C E, Diakun J, Hirsch J
Rockefeller University, New York, NY 10021, USA.
Am J Clin Nutr. 1998 Apr;67(4):631-9. doi: 10.1093/ajcn/67.4.631.
Using new nonisotopic and isotopic methods, we showed previously that fatty acid synthesis was markedly stimulated in weight-stable normal volunteers by a very-low-fat formula diet with 10% of energy as fat and 75% as short glucose polymers. In this study, we determined whether fatty acid synthesis was equally stimulated by a very-low-fat solid diet made with foods consumed typically. Four normal volunteers consumed the same very-low-fat formula diet for 25 d and then an isoenergetic solid food diet with 10% of energy as fat and 75% as starch, simple sugars, and fiber for 25 d. To measure fatty acid synthesis, the fatty acid compositions of the diets were matched to the composition of each subject's adipose tissue and compared with the composition of VLDL-triacylglycerol. In all subjects, the large increases in newly formed palmitate and decreases in linoleate in VLDL-triacylglycerol were quickly reversed by the solid food diet, and the fraction of de novo synthesized fatty acids in fasting VLDL-triacylglycerol decreased from 30-54% to 0-1%. In a second group of subjects, the stimulation of fatty acid synthesis by the formula diet with 75% glucose polymers was similarly reduced by a formula diet with amounts of fat, starch, and sugar chosen to mimic those of the solid food diet, but persisted after the addition of fiber or a diet with 75% sugar. In conclusion, an increase in fatty acid synthesis and palmitaterich, linoleate-poor VLDL-triacylglycerol induced by very-low-fat, high-sugar diets may be reduced by the substitution of dietary starch for sugar with potentially beneficial effects on cardiovascular health.
我们先前使用新的非同位素和同位素方法表明，对于体重稳定的正常志愿者，一种脂肪供能占10%、75%为短链葡萄糖聚合物的极低脂肪配方饮食可显著刺激脂肪酸合成。在本研究中，我们确定由常见食物制成的极低脂肪固体饮食是否能同样刺激脂肪酸合成。四名正常志愿者先食用相同的极低脂肪配方饮食25天，然后食用一种等能量的固体食物饮食，该饮食脂肪供能占10%，75%为淀粉、单糖和纤维，持续25天。为了测量脂肪酸合成，将饮食中的脂肪酸组成与每个受试者脂肪组织的组成相匹配，并与极低密度脂蛋白三酰甘油（VLDL-三酰甘油）的组成进行比较。在所有受试者中，固体食物饮食迅速逆转了VLDL-三酰甘油中新形成的棕榈酸大幅增加和亚油酸减少的情况，空腹VLDL-三酰甘油中从头合成脂肪酸的比例从30%-54%降至0%-1%。在另一组受试者中，脂肪、淀粉和糖含量经选择以模拟固体食物饮食的配方饮食，同样降低了含75%葡萄糖聚合物的配方饮食对脂肪酸合成的刺激作用，但在添加纤维或含75%糖的饮食后这种刺激作用仍然存在。总之，用膳食淀粉替代糖可能会减少极低脂肪、高糖饮食诱导的脂肪酸合成增加以及富含棕榈酸、缺乏亚油酸的VLDL-三酰甘油的生成，这可能对心血管健康产生有益影响。
