Possible Interaction: Caffeine and Insulin

“The mean plasma glucose AUC2h was 28% larger and the mean plasma insulin AUC2h was 19% larger after administration of caffeine than after administration of placebo.”

“ Caffeine ingestion negatively affects insulin sensitivity during an oral glucose tolerance test (OGTT) in lean and obese men, but this has not been studied in individuals with type 2 diabetes.”

“ Insulin area under the curve was 25% greater (P < 0.05) after caffeine than after placebo ingestion.”

“CONCLUSIONS Ca feine ca n decrease ins ulin se nsitivity in healthy humans, possibly as a result of elevated plasma epinephrine levels.”

“RESULTS Ca feine de creased ins ulin se nsitivity by 15% (P < 0.05 vs. placebo).”

“We hypothesized that caffeine reduces insulin sensitivity, either due to catecholamines and/or as a result of blocking adenosine-mediated stimulation of peripheral glucose uptake.”

“ Caffeine also reduced (P < 0.05) GS activity before and during insulin infusion in both legs.”

“Exercise increased insulin sensitivity of leg glucose uptake in both caffeine and placebo.”

“We conclude that 1) caffeine impairs insulin-stimulated glucose uptake and GS activity in rested and exercised human skeletal muscle; 2) caffeine-induced …, or GSK-3alpha but may be associated with increases in epinephrine and intramuscular cAMP concentrations; and 3) exercise reduces the detrimental effects of caffeine … insulin action ….”

“Sal increased basal blood glucose and both Sal and Caf induced significant higher plasma insulin concentrations at rest, at the end of the mock test and during the recovery compared to Pla.”

“The data support our hypothesis that caffeine ingestion results in a greater increase in insulin concentration during an OGTT.”

“Plasma insulin and norepinephrine were lower after caffeine ingestion, whereas an increase in plasma free fatty acids was noted.”

“ Insulin increased uptake by 3.86 ± 1.11 fold when tested alone at 100 nM, and by 3.21 ± 0.80 when combined with caffeine.”

“There is strong evidence that caffeine reduces insulin sensitivity in skeletal muscle and this may be due to a combination of direct antagonism of A(1) receptors and indirectly β-adrenergic stimulation as a result of increased sympathetic activity.”

“The complexity of the latter is illustrated by the observation that insulin counteracted the depression in ATP levels induced not only by adrenaline but by caffeine as well.”