Caffeine increases ambulatory glucose and postprandial responses in coffee drinkers with type 2 diabetes.

R ecent laboratory studies demonstrated that caffeine exaggerates glucose and insulin responses to standardized carbohydrate loads in habitual coffee drinkers who have type 2 diabetes (1–3). Similar postprandial effects in everyday life could disrupt clinical efforts to maintain glucose control in patients with type 2 diabetes. The aim of this study was to examine the effects of a moderate dose of caffeine on glucose levels and postprandial glucose responses in free-living coffee drinkers with type 2 diabetes. We specifically predicted that caffeine administration would increase glucose concentrations during the day and exaggerate the glucose increases that followed meals when habitual coffee drinkers with type 2 diabetes were monitored during everyday life.