Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Canada.
Am J Clin Nutr. 2010 Apr;91(4):966-75. doi: 10.3945/ajcn.2009.28406. Epub 2010 Feb 17.
Dairy protein ingestion before a meal reduces food intake and, when consumed with carbohydrate, reduces blood glucose.
The objective was to describe the effect of whey protein (WP) or its hydrolysate (WPH) when consumed before a meal on food intake, pre- and postmeal satiety, and concentrations of blood glucose and insulin in healthy young adults.
Two randomized crossover studies were conducted. WP (10-40 g) in 300 mL water was provided in experiment 1, and WP (5-40 g) and WPH (10 g) in 300 mL water were provided in experiment 2. At 30 min after consumption, the subjects were fed an ad libitum pizza meal (experiment 1) or a preset pizza meal (12 kcal/kg, experiment 2). Satiety, blood glucose, and insulin were measured at baseline and at intervals both before and after the meals.
In experiment 1, 20-40 g WP suppressed food intake (P < 0.0001) and 10-40 g WP reduced postmeal blood glucose concentrations and the area under the curve (AUC) (P < 0.05). In experiment 2, 10-40 g WP, but not WPH, reduced postmeal blood glucose AUC and insulin AUC in a dose-dependent manner (P < 0.05). The ratio of cumulative blood glucose to insulin AUCs (0-170 min) was reduced by > or =10 g WP but not by 10 g WPH.
WP consumed before a meal reduces food intake, postmeal blood glucose and insulin, and the ratio of cumulative blood glucose to insulin AUCs in a dose-dependent manner. Intact WP, but not WPH, contributes to blood glucose control by both insulin-dependent and insulin-independent mechanisms. This trial was registered at clinicaltrials.gov as NCT00988377 and NCT00988182.
餐前摄入乳蛋白可减少食物摄入量，与碳水化合物同时摄入可降低血糖。
本研究旨在描述健康年轻成年人餐前摄入乳清蛋白（whey protein，WP）或其水解产物（whey protein hydrolysate，WPH）对食物摄入、餐前和餐后饱腹感以及血糖和胰岛素浓度的影响。
进行了两项随机交叉研究。在实验 1 中，受试者在 30 min 内饮用 300 mL 水，其中含有 10-40 g WP；在实验 2 中，受试者在 30 min 内饮用 300 mL 水，其中含有 5-40 g WP 和 10 g WPH。摄入后 30 min，受试者可随意食用一份比萨饼餐（实验 1）或一份预设的比萨饼餐（实验 2，12 kcal/kg）。在基线和餐前及餐后的不同时间点测量饱腹感、血糖和胰岛素。
在实验 1 中，20-40 g WP 可抑制食物摄入（P < 0.0001），10-40 g WP 可降低餐后血糖浓度和曲线下面积（area under the curve，AUC）（P < 0.05）。在实验 2 中，10-40 g WP 可剂量依赖性地降低餐后血糖 AUC 和胰岛素 AUC（P < 0.05），但 WPH 无此作用。0-170 min 时，累积血糖与胰岛素 AUC 比值降低≥10 g WP，但 10 g WPH 无此作用。
餐前摄入 WP 可剂量依赖性地减少食物摄入、餐后血糖和胰岛素以及累积血糖与胰岛素 AUC 比值。完整的 WP 而非 WPH 通过胰岛素依赖和非胰岛素依赖机制来控制血糖。本试验在 clinicaltrials.gov 登记，编号为 NCT00988377 和 NCT00988182。
