Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Canada.
Am J Clin Nutr. 2010 Jan;91(1):98-105. doi: 10.3945/ajcn.2009.28125. Epub 2009 Nov 18.
The glucose-lowering effect of fat and protein is attenuated or absent in diabetic patients, which suggests that the same may occur in insulin-resistant subjects without diabetes.
The objective was to determine whether the postprandial metabolic responses elicited by fat and protein were influenced by the insulin sensitivity of the subjects and whether fat and protein modulate glucose responses through different mechanisms.
Healthy nondiabetic subjects aged 18-45 y took 50 g oral glucose with 0-30-g doses of canola oil and whey protein on 11 separate mornings after fasting overnight. The subjects were classified into 3 fasting serum insulin (FSI) groups: FSI < 40 pmol/L (n = 9), 40 < or = FSI < 70 pmol/L (n = 8), and FSI > or = 70 pmol/L (n = 8). The relative glycemic response was expressed as the incremental area under the curve (AUC) after each test meal divided by the mean AUC of the glucose control in each subject.
Protein significantly decreased glucose (P < 0.0001) and hepatic insulin extraction (P <0.0001) and increased insulin (P < 0.0001) and glucagon-like peptide 1 (P = 0.004); however, protein had no significant effect on C-peptide (P = 0.69) or on the insulin secretion rate (P = 0.13). No significant FSI x fat (P = 0.19) or FSI x protein (P = 0.08) interaction effects on glucose AUC were observed. In addition, the changes in relative glycemic response per gram of fat (r = -0.05, P = 0.82) or protein (r = -0.08, P = 0.70) were not related to FSI.
The hypoglycemic effect of fat and protein was not blunted by insulin resistance. Protein increased insulin but had no effect on C-peptide or the insulin secretion rate, which suggests decreased hepatic insulin extraction or increased C-peptide clearance.
在糖尿病患者中，脂肪和蛋白质的降糖作用减弱或不存在，这表明在没有糖尿病的胰岛素抵抗患者中可能也会出现这种情况。
本研究旨在确定脂肪和蛋白质餐后代谢反应是否受受试者胰岛素敏感性的影响，以及脂肪和蛋白质是否通过不同的机制调节血糖反应。
健康的非糖尿病受试者年龄为 18-45 岁，在禁食过夜后 11 个不同的早晨分别口服 50 g 葡萄糖，并同时摄入 0-30 g 剂量的菜籽油和乳清蛋白。受试者被分为 3 个空腹血清胰岛素（FSI）组：FSI < 40 pmol/L（n = 9）、40 < FSI < 70 pmol/L（n = 8）和 FSI > = 70 pmol/L（n = 8）。相对血糖反应表示为每个测试餐后曲线下面积（AUC）增量除以每个受试者葡萄糖对照的平均 AUC。
蛋白质显著降低了血糖（P < 0.0001）和肝胰岛素提取（P <0.0001），增加了胰岛素（P < 0.0001）和胰高血糖素样肽 1（P = 0.004）；然而，蛋白质对 C 肽（P = 0.69）或胰岛素分泌率（P = 0.13）没有显著影响。未观察到 FSI 与脂肪（P = 0.19）或 FSI 与蛋白质（P = 0.08）之间的交互作用对血糖 AUC 有显著影响。此外，每克脂肪（r = -0.05，P = 0.82）或蛋白质（r = -0.08，P = 0.70）的相对血糖反应变化与 FSI 无关。
脂肪和蛋白质的降血糖作用不受胰岛素抵抗的影响。蛋白质增加了胰岛素，但对 C 肽或胰岛素分泌率没有影响，这表明肝胰岛素提取减少或 C 肽清除增加。
