T Nation

Caffeine=Larger Insulin Response?

Am I understanding this study wrong? Does this mean I shouldn’t be drinking my green tea with meals?

Author

Graham, T E; Sathasivam, P; Rowland, M; Marko, N; Greer, F; Battram, D

Title
Caffeine ingestion elevates plasma insulin response in humans during an oral glucose tolerance test.

Appears In
CANADIAN JOURNAL OF PHYSIOLOGY AND PHARMACOLOGY. vol. 79, no. 7 (2001 Jul): 559-65.

Abstract
We tested the hypothesis that caffeine ingestion results in an exaggerated response in blood glucose and (or) insulin during an oral glucose tolerance test (OGTT). Young, fit adult males (n = 18) underwent 2 OGTT. The subjects ingested caffeine (5 mg/kg) or placebo (double blind) and 1 h later ingested 75 g of dextrose. There were no differences between the fasted levels of serum insulin, C peptide, blood glucose, or lactate and there were no differences within or between trials in these measures prior to the OGTT. Following the OGTT, all of these parameters increased (P < or = 0.05) for the duration of the OGTT. Caffeine ingestion resulted in an increase (P < or = 0.05) in serum fatty acids, glycerol, and plasma epinephrine prior to the OGTT. During the OGTT, these parameters decreased to match those of the placebo trial. In the caffeine trial the serum insulin and C peptide concentrations were significantly greater (P < or = 0.001) than for placebo for the last 90 min of the OGTT and the area under the curve (AUC) for both measures were 60 and 37% greater (P < or = 0.001), respectively. This prolonged, increased elevation in insulin did not result in a lower blood glucose level; in fact, the AUC for blood glucose was 24% greater (P = 0.20) in the caffeine treatment group. The data support our hypothesis that caffeine ingestion results in a greater increase in insulin concentration during an OGTT. This, together with a trend towards a greater rather than a more modest response in blood glucose, suggests that caffeine ingestion may have resulted in insulin resistance.

I wouldnt worry about it.

Firstly, at 5 mg/kg of caffeine, a 180lb person would be consuming about 400 mg of caffeine (about 4 cups of coffee) compared to about 20 mg in an 8 oz serving of green tea. Secondly, A 75g serving of dextrose is a relatively high glycemic load as well - even for post workout.

Lastly, here is an article that paints a different picture: http://www.sciencenews.org/articles/20040117/food.asp

Have you read the Caffine Roundtable article here at T-Nation?

If you haven’t, be sure to do so. It provides a lengthy and balanced discussion of this issue.

My two cents: I don’t drink coffee with meals because I find that it elevates insulin slightly, and more markedly with already high-GI meals. I don’t drink it postworkout, partly because I’ve heard that it interferes with glycogen uptake, but mostly because post-workout is a time for relaxation, not more stimulus. I drink coffee in between meals. That’s more like three cents. Hope it helped.

Thanks guys!

I really, really appreciate all the help and links!!

I’ve always felt that the anti-oxidant anti-cancer effects of green tea by far outweigh the problems of a slightly larger insulin response - I think that everybody should have 2-3 cups every day.