Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota, USA.
Obesity (Silver Spring). 2012 Feb;20(2):349-55. doi: 10.1038/oby.2011.341. Epub 2011 Nov 17.
Dietary interventions that reduce accumulation of body fat are of great interest. Consumption of viscous dietary fibers cause well-known positive metabolic effects, such as reductions in the postprandial glucose and insulin concentrations. However, their effect on body composition and fuel utilization has not been previously studied. To examine this, rats were fed a viscous nonfermentable dietary fiber, hydroxypropyl methylcellulose (HPMC), for 6 weeks. Body composition was measured by dual-energy X-ray absorptiometry (DXA) and fat pad weight. Plasma adipokines, AMP kinase activation, and enzyme and mRNA analysis of key regulators of energetics in liver and soleus muscle were measured. The HPMC diet significantly lowered percent body fat mass and increased percent lean body mass, compared to a cellulose-containing diet (no viscosity). Fasting leptin was reduced 42% and resistin 28% in the HPMC group compared to the cellulose group. Rats fed HPMC had greater activation of AMP kinase in liver and muscle and lower phosphoenolpyruvate carboxykinase (PEPCK) expression in liver. mRNA expression in skeletal muscle was significantly increased for carnitine palmitoyltransferase 1B (CPT-1B), PPARγ coactivator 1α, PPARδ and uncoupling protein 3 (UCP3), as was citrate synthase (CS) activity, in the HPMC group relative to the cellulose group. These results indicate that viscous dietary fiber preserves lean body mass and reduces adiposity, possibly by increasing mitochondrial biogenesis and fatty acid oxidation in skeletal muscle, and thus represents a metabolic effect of viscous fiber not previously described. Thus, viscous dietary fiber may be a useful dietary component to assist in reduction of body fat.
饮食干预措施可减少体脂肪积累，这引起了广泛关注。摄入粘性膳食纤维会产生众所周知的积极代谢效应，如降低餐后血糖和胰岛素浓度。然而，其对身体成分和燃料利用的影响尚未得到研究。为了研究这一问题，我们用粘性不可发酵膳食纤维羟丙基甲基纤维素（HPMC）喂养大鼠 6 周。通过双能 X 射线吸收法（DXA）和脂肪垫重量来测量身体成分。测量血浆 adipokines、AMP 激酶激活以及肝脏和比目鱼肌中能量关键调节剂的酶和 mRNA 分析。与含纤维素的饮食（无粘性）相比，HPMC 饮食显著降低了体脂肪百分比和增加了瘦体重百分比。与纤维素组相比，HPMC 组空腹瘦素降低了 42%，抵抗素降低了 28%。与纤维素组相比，HPMC 喂养的大鼠肝和肌肉中的 AMP 激酶激活增加，肝中磷酸烯醇丙酮酸羧激酶（PEPCK）表达降低。HPMC 组的骨骼肌肉毒碱棕榈酰转移酶 1B（CPT-1B）、过氧化物酶体增殖物激活受体γ共激活因子 1α、PPARδ 和解偶联蛋白 3（UCP3）的 mRNA 表达显著增加，柠檬酸合酶（CS）活性也显著增加。这些结果表明，粘性膳食纤维可保留瘦体重并减少肥胖，这可能是通过增加骨骼肌中线粒体生物发生和脂肪酸氧化实现的，因此代表了以前未描述的粘性纤维的代谢效应。因此，粘性膳食纤维可能是一种有用的饮食成分，有助于减少体脂肪。
