Human Study

ABSTRACT:

Coffee consumption is associated with a lower risk of type 2 diabetes. We tested the hypothesis that this is mediated by incretin hormones by measuring the acute effects of decaffeinated coffee and coffee components on GLP-1 and GIP concentrations. A randomized cross-over trial of the effects of 12 g decaffeinated coffee, 1 g chlorogenic acid, 500 mg trigonelline, and placebo on total and intact GLP-1 and GIP concentrations during an oral glucose tolerance test took place in fifteen overweight men. No treatment significantly affected the overall GLP-1 or GIP secretion pattern following an OGTT relative to placebo. Decaffeinated coffee slightly increased total GLP-1 concentration 30 minutes after ingestion (before the OGTT) relative to placebo (2.7 pmol/L, p = 0.03), but this change did not correspond with changes in glucose or insulin secretion. These findings do not support the hypothesis that coffee acutely improves glucose tolerance through effects on the secretion of incretin hormones. Chronic effects of coffee and its major components still need to be investigated.