Decaffeinated Coffee and Glucose Metabolism

The epidemiological association between coffee drinking and decreased risk of Type 2 diabetes is strong. However, caffeinated coffee acutely impairs glucose metabolism.

This was a randomized, cross-over, placebo-controlled trial of the effects of decaffeinated coffee, caffeinated coffee, and caffeine on glucose, insulin, and glucose-dependent insulinotropic polypeptide (GIP) levels during a 2-h oral glucose tolerance test (OGTT) in 11 young men.

The results showed that within the first hour of the OGTT, glucose and insulin were higher for decaffeinated coffee than for placebo (P < 0.05). During the whole OGTT, decaffeinated coffee yielded higher insulin than placebo and lower glucose and a higher insulin sensitivity index than caffeine. Changes in GIP could not explain any beverage effects on glucose and insulin.

From the results it was concluded that some types of decaffeinated coffee may acutely impair glucose metabolism but less than caffeine.

Diabetes Care February 2010vol. 33 no. 2 278-280