A randomized controlled trial of 16-week consumption of caffeinated and decaffeinated instant coffee on glucose metabolism in overweight men

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 780-806-Determinants of Insulin Resistance & Associated Metabolic Disturbances
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-805
Keizo Ohnaka*, Michiko Kohno, Masahiro Adachi, Hisaya Kawate, Masatoshi Nomura, Suminori Kono and Ryoichi Takayanagi
Kyushu Univ, Fukuoka, Japan
Objective: Observational studies have shown a protective association between coffee consumption and type 2 diabetes mellitus whereas caffeine or caffeinated coffee acutely deteriorates glucose tolerance. We investigated the effects of chronic drinking of instant coffee on glucose and insulin concentrations during a 75g oral glucose tolerance test (OGTT). Methods: Overweight Japanese men aged 40-69 years with a mild-to-moderate elevation of fasting plasma glucose were randomly allocated to a 16-week intervention of consuming 5 cups of caffeinated (n = 17) or decaffeinated (n = 15) instant coffee per day or no coffee (n = 13). Measurement of body composition, blood sampling, and a 75g OGTT were performed at weeks of 0, 8, and 16. Results: No significant difference was observed at baseline characteristics in the three groups. The caffeinated coffee group showed statistically significant decreases in the 2-hour concentrations and the area under the curve of glucose during a 75g OGTT at 16 weeks, while neither decaffeinated coffee nor coffee group showed such a change. Waist circumstance decreased in the caffeinated coffee group, increased in the decaffeinated coffee group, and did not change in the non-coffee group (P = 0.002). With adjustment for the change in waist circumference, caffeinated and decaffeinated coffee consumption were associated with a modest decrease in the postload glucose levels. Conclusion: Both caffeinated and decaffeinated coffee may be protective against deterioration of glucose tolerance.

Nothing to Disclose: KO, MK, MA, HK, MN, SK, RT

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