Robertson Tracey M, Clifford Michael N, Penson Simon, Chope Gemma, Robertson M Denise
1Department of Nutritional Sciences,University of Surrey,Guildford GU2 7WG,UK.
2Department of Primary Production and Processing,Campden BRI,Chipping Campden GL55 6LD,UK.
Br J Nutr. 2015 Oct 28;114(8):1218-25. doi: 10.1017/S0007114515002640. Epub 2015 Aug 28.
Previous studies regarding the acute effects of coffee on glycaemic control have used a single large dose of coffee, typically containing the caffeine equivalent of 2-4 servings of coffee. This study investigates whether the acute effects of coffee are dose-dependent, starting with a single serving. A total of ten healthy overweight males participated in a two-part randomised double-blind cross-over study. In the first part, they ingested 2, 4 or 8 g instant decaffeinated coffee (DC) dissolved in 400 ml water with caffeine added in proportion to the DC (total 100, 200 or 400 mg caffeine) or control (400 ml water) all with 50 g glucose. In the second part, they ingested the same amounts of DC (2, 4, 8 g) or control, but with a standard 100 mg caffeine added to each. Capillary blood samples were taken every 15 min for 2 h after each drink and glucose and insulin levels were measured. Repeated measures ANOVA on glucose results found an effect when caffeine was varied in line with DC (P=0·008). Post hoc analysis revealed that both 2 and 4 g DC with varied caffeine content increased the glycaemic response v.
There was no effect of escalating doses of DC when caffeine remained constant at 100 mg. These results demonstrate that one standard serving of coffee (2 g) is sufficient to affect glucose metabolism. Furthermore, the amount of caffeine found in one serving (100 mg) is sufficient to mask any potential beneficial effects of increasing other components. No dose-dependent effect was found.
以往关于咖啡对血糖控制急性影响的研究使用的是单一大剂量咖啡，通常含有相当于2至4份咖啡的咖啡因量。本研究从单份咖啡开始，探究咖啡的急性影响是否具有剂量依赖性。共有10名健康超重男性参与了一项两部分的随机双盲交叉研究。在第一部分中，他们摄入溶解于400毫升水中的2克、4克或8克速溶脱咖啡因咖啡（DC），并按DC的比例添加咖啡因（咖啡因总量分别为100毫克﹑200毫克或400毫克），或摄入对照物（400毫升水），所有饮品均搭配50克葡萄糖。在第二部分中，他们摄入相同量的DC（2克、4克、8克）或对照物，但每种都添加标准的100毫克咖啡因。每次饮用后每隔15分钟采集毛细血管血样，持续2小时，并测量葡萄糖和胰岛素水平。对葡萄糖结果进行重复测量方差分析发现，当咖啡因随DC变化时存在效应（P = 0·008）。事后分析显示，咖啡因含量不同的2克和4克DC均使血糖反应增加，与对照组相比：当咖啡因保持在100毫克不变时，DC剂量增加没有影响。这些结果表明，一份标准咖啡（2克）足以影响葡萄糖代谢。此外，一份咖啡中所含的咖啡因量（100毫克）足以掩盖增加其他成分可能带来的任何有益影响。未发现剂量依赖性效应。
