Scribner Kelly B, Pawlak Dorota B, Ludwig David S
Children's Hospital Boston, Department of Medicine, 333 Longwood Avenue, Boston, MA 02115, USA.
Obesity (Silver Spring). 2007 Sep;15(9):2190-9. doi: 10.1038/oby.2007.260.
Non-alcoholic fatty liver disease (NAFLD) is fast becoming a major public health concern, coincident with the increasing prevalence of obesity. Although lifestyle greatly influences development of NAFLD, the specific dietary causes remain largely unknown. The purpose of this study was to determine whether a diet high in rapidly absorbed carbohydrate (RAC) vs. slowly absorbed carbohydrate (SAC), controlled for confounding dietary factors, causes NAFLD in mice with similar body weight. An animal model was chosen because of logistical and ethical challenges to conducting this study in humans.
Male 129SvPas mice were fed diets high in either RAC (amylopectin; high glycemic index) or SAC (amylose; low glycemic index) for 25 weeks. Diets were controlled for macronutrient and micronutrient content, differing only in starch type. Body weight and composition were measured throughout the study. Hepatic and plasma triacylglycerol concentrations were quantified at the end of the study.
Body weight was not significantly different between the two groups. However, total body adiposity increased twice as much, in absolute terms, in the mice fed RAC vs. SAC (12.2 +/- 2.9% vs. 6.1 +/- 4.2%, p < 0.0001). Hepatic triacylglycerol content was 2-fold greater in the RAC group (20.7 +/- 9.4 vs. 9.6 +/- 4.9 mg/g, p = 0.01). In addition, plasma insulin and triacylglycerol concentrations were higher in the RAC group.
A diet high in RAC causes accumulation of fat in liver, adipose tissue, and plasma in mice. Therefore, a low glycemic index diet may help prevent or treat NAFLD in humans.
非酒精性脂肪性肝病（NAFLD）正迅速成为一个主要的公共卫生问题，这与肥胖患病率的上升相一致。尽管生活方式对NAFLD的发展有很大影响，但具体的饮食原因在很大程度上仍不清楚。本研究的目的是确定在控制混杂饮食因素的情况下，高快速吸收碳水化合物（RAC）饮食与缓慢吸收碳水化合物（SAC）饮食相比，是否会导致体重相似的小鼠发生NAFLD。由于在人类中进行这项研究存在后勤和伦理挑战，因此选择了动物模型。
给雄性129SvPas小鼠喂食高RAC（支链淀粉；高血糖指数）或SAC（直链淀粉；低血糖指数）的饮食25周。饮食在常量营养素和微量营养素含量方面得到控制，仅淀粉类型不同。在整个研究过程中测量体重和身体组成。在研究结束时对肝脏和血浆三酰甘油浓度进行定量。
两组之间体重无显著差异。然而，喂食RAC的小鼠总体脂绝对增加量是喂食SAC小鼠的两倍（12.2±2.9%对6.1±4.2%，p<0.0001）。RAC组肝脏三酰甘油含量高2倍（20.7±9.4对9.6±4.9mg/g，p = 0.01）。此外，RAC组血浆胰岛素和三酰甘油浓度更高。
高RAC饮食会导致小鼠肝脏、脂肪组织和血浆中脂肪堆积。因此，低血糖指数饮食可能有助于预防或治疗人类的NAFLD。
