Brand-Miller J C, Thomas M, Swan V, Ahmad Z I, Petocz P, Colagiuri S
Human Nutrition Unit, School of Molecular and Microbial Biosciences, University of Sydney, Sydney, NSW, Australia.
J Nutr. 2003 Sep;133(9):2728-32. doi: 10.1093/jn/133.9.2728.
Dietary glycemic load, the mathematical product of the glycemic index (GI) of a food and its carbohydrate content, has been proposed as an indicator of the glucose response and insulin demand induced by a serving of food. To validate this concept in vivo, we tested the hypotheses that 1). portions of different foods with the same glycemic load produce similar glycemic responses; and 2). stepwise increases in glycemic load for a range of foods produce proportional increases in glycemia and insulinemia. In the first study, 10 healthy subjects consumed 10 different foods in random order in amounts calculated to have the same glycemic load as one slice of white bread. Capillary blood samples were taken at regular intervals over the next 2 h. The glycemic response as determined by area under the curve was not different from that of white bread for nine foods. However, lentils produced lower than predicted responses (P < 0.05). In the second study, another group of subjects was tested to determine the effects of increasing glycemic load using a balanced 5 x 5 Greco-Latin square design balanced for four variables: subject, dose, food and order. Two sets of five foods were consumed at five different glycemic loads (doses) equivalent to one, two, three, four and six slices of bread. Stepwise increases in glycemic load produced significant and predictable increases in both glycemia (P < 0.001) and insulinemia (P < 0.001). These findings support the concept of dietary glycemic load as a measure of overall glycemic response and insulin demand.
膳食血糖负荷是食物的血糖指数（GI）与其碳水化合物含量的数学乘积，已被提议作为一份食物所诱导的葡萄糖反应和胰岛素需求的指标。为了在体内验证这一概念，我们检验了以下假设：1）具有相同血糖负荷的不同食物份量会产生相似的血糖反应；以及2）一系列食物的血糖负荷逐步增加会使血糖和胰岛素水平成比例增加。在第一项研究中，10名健康受试者以随机顺序食用10种不同食物，食用量经计算与一片白面包具有相同的血糖负荷。在接下来的2小时内定期采集毛细血管血样。由曲线下面积确定的九种食物的血糖反应与白面包的血糖反应无差异。然而，小扁豆产生的反应低于预期（P < 0.05）。在第二项研究中，另一组受试者接受测试，以使用平衡的5×5希腊-拉丁方设计来确定增加血糖负荷的影响，该设计针对四个变量进行了平衡：受试者、剂量、食物和顺序。两组五种食物以相当于一、二、三、四和六片面包的五种不同血糖负荷（剂量）食用。血糖负荷的逐步增加导致血糖（P < 0.001）和胰岛素水平（P < 0.001）均出现显著且可预测的增加。这些发现支持了膳食血糖负荷这一概念，即作为整体血糖反应和胰岛素需求的一种度量。
