Table 1

Glucose, insulin, and GIP concentrations and AUC during an OGTT following ingestion of placebo, decaffeinated coffee, caffeinated coffee, and caffeine in 11 healthy young men

T = −90T = −60T = 0T = 10T = 30T = 60T = 90T = 1203-h AUC
Glucose (mmol/l)
    Placebo4.50 ± 0.154.25 ± 0.144.35 ± 0.194.57 ± 0.20a6.66 ± 0.28a7.38 ± 0.706.95 ± 0.795.45 ± 0.574.35 ± 1.01a,b
    Decaffeinated coffee4.55 ± 0.174.34 ± 0.164.44 ± 0.185.25 ± 0.28b8.13 ± 0.41b6.86 ± 0.615.99 ± 0.485.09 ± 0.454.1 ± 0.67b
    Caffeinated coffee4.29 ± 0.144.29 ± 0.094.62 ± 0.115.51 ± 0.26b7.63 ± 0.39b8.11 ± 0.437.14 ± 0.325.96 ± 0.355.63 ± 0.38a,b
    Caffeine4.33 ± 0.134.18 ± 0.144.31 ± 0.125.04 ± 0.18b7.44 ± 0.26b7.87 ± 0.757.00 ± 0.696.05 ± 0.645.39 ± 0.80a
Insulin (Φmol /l)
    Placebo105.3 ± 33.385.1 ± 25.671.2 ± 17.4124.8 ± 21.7a331.2 ± 51.8a421.4 ± 44.0a413.4 ± 51.2296.4 ± 55.2489.4 ± 75.8a
    Decaffeinated coffee114.7 ± 28.480.2 ± 11.071.0 ± 9.9231.0 ± 54.8b537.4 ± 97.1b518.1 ± 56.7b489.8 ± 99.7316.3 ± 54.5705.5 ± 109.8b
    Caffeinated coffee102.7 ± 22.787.7 ± 10.775.7 ± 9.1238.4 ± 59.1b544.7 ± 97.4b626.2 ± 109.6b692.3 ± 140.7457.2 ± 110.0884.9 ± 159.4b
    Caffeine113.3 ± 29.0103.7 ± 30.176.9 ± 10.8202.9 ± 32.8b555.8 ± 85.6b717.8 ± 127.3b669.8 ± 140.1480.8 ± 124.8882.0 ± 185.9b
GIP (pg/ml)
    Placebo68.8 ± 15.365.0 ± 14.658.4 ± 16.9a106.7 ± 17.7157.3 ± 18.2164.6 ± 17.1166.0 ± 18.4143.2 ± 17.9164.9 ± 23.0a
    Decaffeinated coffee131.0 ± 31.991.3 ± 18.544.2 ± 7.1b130.4 ± 13.4187.4 ± 24.7173.8 ± 20.4160.1 ± 19.0136.9 ± 16.9109.4 ± 35.6a
    Caffeinated coffee83.5 ± 24.972.3 ± 14.043.8 ± 8.5a,b120.2 ± 22.0158.3 ± 23.2148.1 ± 17.8134.1 ± 12.9124.0 ± 13.4112.7 ± 30.2a
    Caffeine88.0 ± 29.177.7 ± 19.667.2 ± 10.8a141.3 ± 28.3174.6 ± 27.3166.8 ± 20.5159.3 ± 21.7139.2 ± 21.7150.8 ± 34.6a
  • Data are means ± SEM. n = 11. T denotes time point in minutes. Initial values (T = −90 min) are fasting values. Beverage ingested at T = −60 min. OGTT started at T = 0 min. ISI was based on the formula of Belfiore et al. (11). Three-hour AUC was calculated between T = −60 and T = 120. Means in a column with different letter superscripts differ significantly (P < 0.05), by two-way repeated-measures ANOVA for glucose and insulin and by one-way repeated-measures ANOVA for 3-h AUC. Post-hoc tests adjusted for multiple comparisons by means of a Tukey test.