Morens C, Sirot V, Scheurink A J W, van Dijk G
Department of Neuroendocrinology, Center for Behavior and Neurosciences, University of Groningen, 9750 AA Haren, The Netherlands.
Am J Physiol Regul Integr Comp Physiol. 2006 Dec;291(6):R1622-9. doi: 10.1152/ajpregu.00128.2006. Epub 2006 Aug 10.
In parallel with increased prevalence of overweight people in affluent societies are individuals trying to lose weight, often using low-carbohydrate diets. Nevertheless, long-term metabolic consequences of those diets, usually high in (saturated) fat, remain unclear. Therefore, we investigated long-term effects of high-fat diets with different carbohydrate/protein ratios on energy balance and fuel homeostasis in obese (fa/fa) Zucker and lean Wistar rats. Animals were fed high-carbohydrate (HC), high-fat (HsF), or low-carbohydrate, high-fat, high-protein (LC-HsF-HP) diets for 60 days. Both lines fed the LC-HsF-HP diet displayed reduced energy intake compared with those fed the HsF diet (Zucker, -3.7%) or the HC diet (Wistar rats, -12.4%). This was not associated with lower weight gain relative to HC fed rats, because of increased food efficiencies in each line fed HsF and particularly LC-HsF-HP food. Zucker rats were less glucose tolerant than Wistar rats. Lowest glucose tolerances were found in HsF and particularly in LC-HsF-HP-fed animals irrespective of line, but this paralleled reduced plasma adiponectin levels, elevated plasma resistin levels, higher retroperitoneal fat masses, and reduced insulin sensitivity (indexed by insulin-induced hypoglycemia) only in Wistar rats. In Zucker rats, however, improved insulin responses during glucose tolerance testing and tendency toward increased insulin sensitivities were observed with HsF or LC-HsF-HP feeding relative to HC feeding. Thus, despite adverse consequences of LC-HsF diets on blood glucose homeostasis, principal differences exist in the underlying hormonal regulatory mechanisms, which could have benefits for B-cell functioning and insulin action in the obese state but not in the lean state.
在富裕社会中，超重人群不断增加，与此同时，也有许多人试图减肥，他们常常采用低碳水化合物饮食。然而，这些通常富含（饱和）脂肪的饮食对长期代谢的影响仍不明确。因此，我们研究了不同碳水化合物/蛋白质比例的高脂肪饮食对肥胖（fa/fa） Zucker大鼠和瘦的Wistar大鼠能量平衡及燃料稳态的长期影响。给动物喂食高碳水化合物（HC）、高脂肪（HsF）或低碳水化合物、高脂肪、高蛋白（LC-HsF-HP）饮食60天。与喂食HsF饮食的大鼠（Zucker大鼠，-3.7%）或HC饮食的大鼠（Wistar大鼠，-12.4%）相比，两种品系喂食LC-HsF-HP饮食的大鼠能量摄入均减少。这与相对于喂食HC饮食的大鼠体重增加较少无关，因为喂食HsF尤其是LC-HsF-HP食物的每个品系食物效率都有所提高。Zucker大鼠的葡萄糖耐量低于Wistar大鼠。无论品系如何，在喂食HsF尤其是LC-HsF-HP的动物中葡萄糖耐量最低，但这仅在Wistar大鼠中与血浆脂联素水平降低、血浆抵抗素水平升高、腹膜后脂肪量增加以及胰岛素敏感性降低（以胰岛素诱导的低血糖为指标）相关。然而，在Zucker大鼠中，相对于喂食HC饮食，喂食HsF或LC-HsF-HP饮食时，在葡萄糖耐量试验中观察到胰岛素反应改善以及胰岛素敏感性有增加的趋势。因此，尽管LC-HsF饮食对血糖稳态有不良影响，但潜在的激素调节机制存在主要差异，这可能对肥胖状态下的B细胞功能和胰岛素作用有益，但对瘦状态则不然。
