Division of Nutritional Sciences, University of Illinois, Urbana, IL 61801, USA.
Nutr Metab (Lond). 2011 Mar 4;8(1):13. doi: 10.1186/1743-7075-8-13.
The Dietary Reference Intakes (DRI) established acceptable macronutrient distribution ranges (AMDR) for carbohydrates and protein, however little is known about differences in glycemic regulations and metabolic signaling across this range. This study examined metabolic outcomes associated with intake of two diets differing in carbohydrate:protein ratios representing the upper and lower ends of the AMDR.
Adult, male rats were fed either a high carbohydrate (CHO) diet (60% of energy from carbohydrates, 12% protein, 28% fat; n = 30) or a high protein (PRO) diet (35% carbohydrate, 35% protein, 30% fat; n = 30). Rats were meal-fed 3x/d the respective diets for 10 d and then terminated after overnight food deprivation or 30, 60, 90, 120 min post-prandial (PP). Plasma was collected at each of these points to provide a time course for glucose, insulin and C-peptide. Skeletal muscle and adipose tissues were collected at 0, 30 and 90 min for measurements of basal, early and delayed activation of Akt, p70S6K and Erk 1/2. Data were analyzed by two-way ANOVA.
The CHO group produced a consistently elevated response in plasma glucose, insulin and C-peptide following the meal through the 120 min time course. In addition, Akt and Erk 1/2 activation in adipose was much higher than in skeletal muscle. Conversely, the PRO group PP glucose response was minimal and insulin maintained a response similar to a biphasic pattern. Tissue responses for the PRO group were greater for Akt and p70S6K signaling in skeletal muscle compared with adipose.
Taken together these data suggest that altering CHO:PRO ratios within the AMDR produce different glycemic response patterns accompanied by differential metabolic signaling in skeletal muscle and adipose.
膳食参考摄入量（DRI）为碳水化合物和蛋白质确定了可接受的宏量营养素分布范围（AMDR），然而，人们对这个范围内的血糖调节和代谢信号差异知之甚少。本研究考察了两种不同碳水化合物：蛋白质比例饮食摄入与代谢结果的关系，这两种饮食分别代表 AMDR 的上限和下限。
成年雄性大鼠分别喂食高碳水化合物（CHO）饮食（碳水化合物供能 60%，蛋白质 12%，脂肪 28%；n = 30）或高蛋白（PRO）饮食（碳水化合物 35%，蛋白质 35%，脂肪 30%；n = 30）。大鼠每天 3 次进食相应的饮食 10 天，然后在隔夜禁食或餐后 30、60、90、120 分钟时终止。在这些时间点采集血浆，提供血糖、胰岛素和 C 肽的时间过程。在 0、30 和 90 分钟时采集骨骼肌和脂肪组织，用于测量 Akt、p70S6K 和 Erk 1/2 的基础、早期和延迟激活。数据采用双因素方差分析进行分析。
CHO 组在餐后 120 分钟的时间过程中，血浆葡萄糖、胰岛素和 C 肽持续升高。此外，脂肪组织中的 Akt 和 Erk 1/2 激活比骨骼肌高得多。相反，PRO 组的餐后血糖反应很小，胰岛素保持类似双相的反应模式。与脂肪组织相比，PRO 组骨骼肌中的 Akt 和 p70S6K 信号对组织的反应更大。
总的来说，这些数据表明，在 AMDR 内改变 CHO：PRO 比例会产生不同的血糖反应模式，并伴有骨骼肌和脂肪代谢信号的差异。
