Wednesday, March 14, 2012

Only "Real", Not Decaffeinated Instant Coffee Increases Fatty Acid Oxidation. Revisited: Caffeine's Dose-Dependent Effects on Testosterone & Cortisol Response to Exercise

Image 1: Coffee is made of coffee beans! Hard to believe if you look at what remains of this precious superfood in a sachet with instant "coffee", right? But is instant, let alone "decaf" + instant really as bad as its rep?
Although I know that probably not everyone is going to agree with that, I personally believe that coffee is one of the few real "superfood"... if it still is coffee and not some sort of adulterated lifestyle drink with synthetic caffeine and coffee-aroma. Those of you who like to enjoy their morning coffee (or tea) with tiny dose of SuppVersity news, will probable remember the "Warding Off Holiday Weight Gain"-posts in which I already broached the issue of the metabolic benefits of real coffee. With a coffee and a caffeine arm, the said rodent study did yet not provide any clues about the benefits or downsides of "decaf", i.e. de-caffeinated coffee, the supposedly "healthier" alternative to the stimulating brown brew, which has once been a prerogative of kings and popes and has as of late been turned into a lifestyle drink by the clever marketing campaigns of Starbucks & Co.

Instant Defac before exercise? That does not make sense, right?

In their study, Donrawee Leelarungrayub, Maliwan Sallepan and Sukanya Charoenwattana from the Chiang Mai and Burapha Universities in Thailand tried to get to the bottom of the question of whether or not the acute ingestion of coffee (not caffeine or stimulant loaden pre-workout products) would exert any beneficial or detrimental effects on the energy utilization and antioxidant capacity of 26 healthy and normal-weight, but non-athletic (=mainly sedentary ;-) men. The subjects who were assigned to one out of three study groups
  1. regular coffee - at a dose that would deliver 5mg/kg body weight (for a 70kg Thai this would be 350mg or 1-2 large cups of coffee)
  2. decaffeinated coffee - at an identical dose, yet prepared with instant freeze dried decaffeinated  coffee from Expressor, Thailand
  3. placebo - unfortunately the scientists do give any further information on the placebo group, other than stating that they received "no supplement", if this means that groups 1 and 2 ingested fluids, while group 3 did not, this would be a minor flaw in the study design
and performed a standardized exercise protocol on the treadmill where speed and slope were increased in three-minute intervals Directed VO2 and RER (respiratory exchange ration = measure of carbohydrate to fat oxidation; lower values indicate higher fat oxidation) were analysed automatically by the Breeze-Suit Software program.

Real men (and women) drink real coffee... at least if their goal is fat loss ;-)

The VO2 and RER values you see in figure 1 were taken, when the heart rate of the subjects had climbed to 80% of their maximal heart rate and could be interpreted as being indicative of what you would see during the high intensity phases of a short high intensity (yet not all out) interval training (HIIT) regimen. Unfortunately trial 1 (without coffee) and trial 2 (with coffee) were performed subsequently, it is thusly no wonder that the oxygen consumption increased and the RER dropped in all three conditions - a similar effect is seen, when you perform your "cardio" training after your resistance training sessions, when the decreased glucose availability forces your body to burn more fat.
Figure 1: Differences in VO2 consumption, respiratory exchange ratio (RER), blood glucose and malondialdehyde (MDA) in trial one (unsupplemented) vs. trial two (supplemented; data based on Leelarungrayub. 2012)
The statistical insignificance of the changes in the control and decaffeinated coffee group do yet suggest that the respective increases and decreases in the "real" coffee (with caffeine) group are independent of any kind of "priming" effect due to previous exercise - an assumption that is reinforced by the >4% higher post-exercise glucose levels (compared to the non-supplemented trial) in the caffeinated coffee trial and the oppositional decrease of the latter in the decaf and the control groups.

If you just want the antioxidant effects, decaffeinated coffee seems to be fine, though

What is yet somewhat unresting is the profound +71% increase in MDA levels in the regular coffee group. And while the change in total antioxidant capacity (TAC; not shown in figure 1) was not statistically significant in either of the groups, it is still quite telling that - all statistical shenanigan aside - the subject who consumed the decaffeinated coffee were the only ones, where the TAC values increased from the pre- (control) to the post (supplementation) test.
Image 2: If you still belive that temporary increases in testosterone build muscle and cortisol needs to be eradicated at all costs, you better (re-)read the Intermittent Thoughts
Whenever the topic "caffeine and exercise", it is more or less imperative that someone is going to ask about its effects on cortisol (and testosterone), thusly I would like to take this opportunity to briefly cite the results of one of the few studies which actually deals with the effects of different amounts of caffeine on the testosterone and cortisol responses to exercise: The study was conducted with 24 professional rugby players who were randomly assigned to receive 0, 200, 400 or 800mg of caffeine 1h before performing a standardized resistance training protocol (Beavan. 2008). Contrary to what bro-science has been suggesting for years (meanwhile many bros are aware of this study, so that this is about to change ;-) the ingestion of the lower doses 200mg and 400mg) of caffeine did not lead to statistically significant increases in cortisol, but blunted its decrease half-way into the workout. Against that background and in view of the fact that all three doses of caffeine increased the testosterone response to the workout (+15% increase in testosterone in the 200mg and 400mg group and an additional +21% in the 800mg group), the "small" amount of 200mg still appears to be the most prudent (and sustainable!) way to promote fatty acid oxidation (as shown in the study at hand) and exercise performance (by avoiding the potentially ergolytic drop in cortisol levels during the workouts). That the temporary increase in testosterone levels around workouts is not worth a penny, is something you, as an educated SuppVersity reader should be aware of, anyhow (if not re-read the Intermittent Thoughts on Building Muscle series, please)
If we assume that none, or at least only insignificant amounts of the other bioactive components of the coffee got lost during the decaffeination process, this is yet another clear-cut evidence that at least some of the discrepancies between various studies on the potential benefits and down-sides of coffee consumption could simply be attributed to the fact that many of the coffee-skeptics base their arguments on caffeine-only studies. A recent study from Horticulture and Food Research Institute of New Zealand, in which the researchers used a caffeine and diterpenoid rich Colombian coffee extract as a means to attenuated impairment in glucose tolerance, hypertension, cardiovascular remodeling, and nonalcoholic fatty liver disease without changing abdominal obesity and dyslipidemia in a rodent model of metabolic syndrome (Panchal. 2012), does yet prove that there are scientists who appreciate the value of complex natural nutrient matrices and start to exploit the value of (in the broadest sense) medicinal effects of whole foods instead of trying to isolate their allegedly "effective" ingredients.