Consumption of decaffeinated coffee with milk and sugar added before a high-glycemic-index meal lowers postprandial glucose surge when compared with consuming it after the meal

This study aimed to compare the effect of consuming decaffeinated coffee at different times around a high glycemic index (GI) meal on postprandial glycemic responses. Ten healthy adults completed this randomized, crossover trial. In each session, overnight-fasted participants consumed the test drink, which was a cup of decaffeinated coffee with low-fat milk and white sugar added, at different timepoints before or after a high GI meal. Postprandial levels of glucose, insulin, and nitrotyrosine at individual timepoints, as well as the area-under-curves (AUC), were compared among the treatments using mixed-effect linear model. Results showed that consuming the test drink 30 and 60 min before the high GI meal (glucose AUC ± SE: 862.6 ± 24.8 and 861.4 ± 24.8 mmol * 120 min/L, respectively) led to significantly reduced glycemic responses when compared with consuming it after the meal (952.7 ± 24.8 mmol * 120 min/L, p < 0.05 compared with either treatment). Drinking the test drink at least 30 min before the meal also led to smaller insulinemic responses, while nitrotyrosine levels were not significantly different between different consumption times. These showed that consuming decaffeinated coffee with milk and sugar added at least 30 min before a meal could benefit postprandial glycemic control.