|"Done,... where is my post-workout coffee?" - Post workout caffeine / chlorogenic acid - good or bad idea?|
Not all are really news-worthy, but aside from today's item on caffeine and chlorogenic acid, there were also posters on nutrient timing, different forms of protein, commercially available supplements and other stuff that's all classic "SuppVersity fodder"?
learn moreCaffeine and chlorogenic acid? Right, that sounds like green coffee bean extract, but in the case of Jason R Beam et al.'s study, we are dealing with an artificial stack of
- 5mg/kg body weight of caffeine plus 75 g of dextrose (CAF),
- 5 mg/kg body weight of chlorogenic acid plus 75 g of dextrose (CGA), or
- 5 mg/body weight of dextrose plus 75 g dextrose (PLA)
"Ok, no caffeine after a workout - right!?"
In the case of caffeine that was to be expected, it has after all been shown to decrease the insulin-induced glucose uptake (Graham. 2001). The fact that the glycemic response was - within the statistically probable margins - still identical, is simply the result that the stimulation of glucose uptake and hepatic, as well as muscular glucose storage is not really necessary as long at the glycogen stores are low. Accordingly, a 2004 study by Battram et al. was unable to show any effect of caffeine ingestion on proglycogen and macroglycogen resynthesis after a workout (Battram. 2004).
If we discard potential negative effects of the caffeine-induced CNS activation on post-exercise nervous system recovery, and take into account that the elevated glucose + insulin AUC Beam observed in the experiments for his dissertation and ISSN conference poster are negligible, the preliminary bottom line for post-workout caffeine intake would be: "If glycogen resynthesis is what you are looking for, do it!"
"The increase [in p-AKT] tended to be higher after the ingestion of caffeine with CHO after both 1 and4hof recovery, but failed to reach statistical significance. Akt seems to regulate glucose uptake by phosphorylating and inhibiting the Rab-GTPase-activating protein AS160. Thus it is tempting to speculate on the role of Akt in glucose transport given that the Akt substrate AS160 has been identified as an important regulator of GLUT4 traffic.
You think you've heard about p-Akt before, but are not sure where? Well, chances are it was here at the SuppVersity, yet probably in a different context, i.e. as part of the Intermittent Thoughts on Building Muscle | read more
We have recently shown that AS160 is phosphorylated in human skeletal muscle after endurance exercise with concomitant phosphorylation of Akt (7), providing correlative evidence to suggest AS160 is an exercise-responsive protein with a role in glucose uptake." (Pederson. 2009)
"What about the effects of chlorogenic acid. Shouldn't the exact opposite happen?"
Now that we've searched for explanations of the effects of caffeine on post-workout glycemia we are still left with the astonishing increase in the two-hour glucose area under the curve, i.e. total glycemia, Beam observed in the glucose + chlorogenic arm of his study.
|Figure 3: Insulin (AUC) for each subject during the placebo, caffeine, and chlorogenic acid trials (Beam. 2013)|
In this particular case the 2 outliers, subject 1 and subject 6 do not simply "ruin" the statistical significance, they are actually the (almost) only reason that insulin response is not virtually identical to the placebo trial.
As far as potential negative consequences of the post-workout consumption of cholorgenic acid goes, you do thus not have to be worried, whether it is actually a good idea to use a supplement that's meant to increase the activity of AMPK in a phase, when the latter is already maximized, is however questionable. In the best case, the additional benefits will be minimal, in the worst case it CGA will ruin the glucose repartitioning effects of the workout by increasing AMPK and thus glucose uptake in the fat cells (Alonso-Castro. 2008).
- Alonso-Castro, A. J., Miranda-Torres, A. C., González-Chávez, M. M., & Salazar-Olivo, L. A. (2008). Cecropia obtusifolia Bertol and its active compound, chlorogenic acid, stimulate 2-NBD glucose uptake in both insulin-sensitive and insulin-resistant 3T3 adipocytes. Journal of ethnopharmacology, 120(3), 458-464.
- Beam, J. (2013). The effect of post-exercise caffeine and chlorogenic acid supplementation on blood glucose disposal and insulin sensitivity.
- Battram, D. S., Shearer, J., Robinson, D., & Graham, T. E. (2004). Caffeine ingestion does not impede the resynthesis of proglycogen and macroglycogen after prolonged exercise and carbohydrate supplementation in humans. Journal of Applied Physiology, 96(3), 943-950.
- Pedersen, D. J., Lessard, S. J., Coffey, V. G., Churchley, E. G., Wootton, A. M., Ng, T., ... & Hawley, J. A. (2008). High rates of muscle glycogen resynthesis after exhaustive exercise when carbohydrate is coingested with caffeine. Journal of Applied Physiology, 105(1), 7-13.