Decaffeinated coffee and glucose metabolism in young men.

doi:10.2337/dc09-1539

Decaffeinated coffee and glucose metabolism in young men.

James A. Greenberg, PhD (jamesg{at}brooklyn.cuny.edu)¹,
David R. Owen, PhD² and
Allan Geliebter, PhD³

1 - Department of Health & Nutrition Sciences, Brooklyn College of the City University of New York, New York City, NY, USA
2 - Department of Psychology, Brooklyn College of the City University of New York, New York City, NY, USA
3 – Department of Psychology, Columbia University & New York Obesity Research Center, St. Luke's-Roosevelt Hospital Center, New York City, NY, USA

Abstract

Objective: The epidemiological association between coffee drinking and decreased risk of type 2 diabetes is strong. However, caffeinated coffee acutely impairs glucose metabolism. We assessed acute effects of decaffeinated coffee on glucose and insulin levels.

Research design and methods: 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 two-hour oral glucose tolerance test (OGTT) in eleven young men.

Results: 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.

Conclusions: Some types of decaffeinated coffee may acutely impair glucose metabolism, but less than caffeine.