正常胰岛素血症和高胰岛素血症受试者在摄入高脂肪、低碳水化合物和低脂肪、高碳水化合物等能量饮食时的肝脏从头脂肪生成。

Hepatic de novo lipogenesis in normoinsulinemic and hyperinsulinemic subjects consuming high-fat, low-carbohydrate and low-fat, high-carbohydrate isoenergetic diets.

作者信息

Schwarz Jean-Marc, Linfoot Peter, Dare Doris, Aghajanian Karmen

机构信息

Department of Nutritional Sciences and Toxicology, University of California, Berkeley 94720-3104, USA.

出版信息

Am J Clin Nutr. 2003 Jan;77(1):43-50. doi: 10.1093/ajcn/77.1.43.

DOI:10.1093/ajcn/77.1.43

PMID:12499321

Abstract

BACKGROUND

Hypertriglyceridemia is associated with increased risk of cardiovascular disease. Until recently, the importance of hepatic de novo lipogenesis (DNL) in contributing to hypertriglyceridemia was difficult to assess because of methodologic limitations.

OBJECTIVE

We evaluated the extent of the contribution by DNL to different conditions associated with hypertriglyceridemia.

DESIGN

After 5 d of an isoenergetic high-fat, low-carbohydrate diet, fasting DNL was measured in normoinsulinemic (<or= 85 pmol/L) lean (n = 9) and obese (n = 6) and hyperinsulinemic (>or= 115 pmol/L) obese (n = 8) subjects. Fasting DNL was measured after a low-fat, high-carbohydrate diet in normoinsulinemic lean (n = 5) and hyperinsulinemic obese (n = 5) subjects. Mass isotopomer distribution analysis was used to measure the fraction of newly synthesized fatty acids in VLDL-triacylglycerol.

RESULTS

With the high-fat, low-carbohydrate diet, hyperinsulinemic obese subjects had a 3.7-5.3-fold higher fractional DNL (8.5 +/- 0.7%) than did normoinsulinemic lean (1.6 +/- 0.5%) or obese (2.3 +/- 0.3%) subjects. With the low-fat, high-carbohydrate diet, normoinsulinemic lean and hyperinsulinemic obese subjects had similarly high fractional DNL (13 +/- 5.1% and 12.8 +/- 1.4%, respectively). Compared with baseline, consumption of the high-fat, low-carbohydrate diet did not affect triacylglycerol concentrations. However, after the low-fat, high-carbohydrate diet, triacylglycerols increased significantly and DNL was 5-6-fold higher than in normoinsulinemic subjects consuming a high-fat diet. The increase in triacylglycerol after the low-fat, high-carbohydrate diet was correlated with fractional DNL (P < 0.01), indicating that subjects with high DNL had the greatest increase in triacylglycerols.

CONCLUSIONS

These results support the concept that both hyperinsulinemia and a low-fat diet increase DNL, and that DNL contributes to hypertriglyceridemia.

摘要

背景

高甘油三酯血症与心血管疾病风险增加相关。直到最近，由于方法学上的局限性，肝脏从头脂肪生成（DNL）在导致高甘油三酯血症中的重要性难以评估。

目的

我们评估了DNL对与高甘油三酯血症相关的不同情况的贡献程度。

设计

在进行5天等能量高脂肪、低碳水化合物饮食后，测量正常胰岛素水平（≤85 pmol/L）的瘦人（n = 9）和肥胖者（n = 6）以及高胰岛素水平（≥115 pmol/L）的肥胖者（n = 8）的空腹DNL。在正常胰岛素水平的瘦人（n = 5）和高胰岛素水平的肥胖者（n = 5）进行低脂、高碳水化合物饮食后测量空腹DNL。采用质量同位素异构体分布分析来测量极低密度脂蛋白 - 三酰甘油中新合成脂肪酸的比例。

结果

采用高脂肪、低碳水化合物饮食时，高胰岛素水平的肥胖者的DNL分数（8.5±0.7%）比正常胰岛素水平的瘦人（1.6±0.5%）或肥胖者（2.3±0.3%）高3.7 - 5.3倍。采用低脂、高碳水化合物饮食时，正常胰岛素水平的瘦人和高胰岛素水平的肥胖者的DNL分数同样高（分别为13±5.1%和12.8±1.4%）。与基线相比，高脂肪、低碳水化合物饮食的摄入未影响三酰甘油浓度。然而，在低脂、高碳水化合物饮食后，三酰甘油显著增加，且DNL比食用高脂肪饮食的正常胰岛素水平受试者高5 - 6倍。低脂、高碳水化合物饮食后三酰甘油的增加与DNL分数相关（P < 0.01），表明DNL高的受试者三酰甘油增加最多。