Green Tea Extracts for Building Strength & Size and Losing Weight - Fact or Fraud? Or, Why It is Always Worth Taking a Look at the Data that Is NOT in the Abstract.

Image 1: If the watery green tea is healthy, then a potent extract must be even more healthy, right? This may well be just another instance of "supplementational idiocy"...

I know people love their Green Tea! After all, Camellia sinensis is one of the staples that has not yet been debunked as another hoax of the supplement of pharmaceutical industry - a real healthfood, right!? Well, you will probably be familiar with my skepticisms towards the notion that taking tons of the polyphenols you are "supposed" to get in relatively small quantities from 2-3 cups of green tea in supplemental form must necessarily be a good thing, just because epidemiological data suggests that people who consume green tea (for those who only now this stuff in capped form: Green tea is actually a beverage ;-) in moderation are overall healthier than people who abstain from drinking hot water extracts (=tea) from minimally oxidized (=green) Camellia sinensis leaves.

Did you miss my previous blogposts on the negative effects of high dose green tea extracts on testosterone levels and male fertility? If so, I suggest you read up on that one before adopting the (stupid) more-is-more principal and popping the whole box of green tea caps at once.

Two recent studies do confirm the notion that green tea, even as a supplement, may be a worthwile addition to your dietary (I suggest you drink the tea not use the supplement) or supplemental (if you cannot stand the taste of the brew) regimen. The first one comes from scientists from the University of Warsaw in Poland (Jówoko. 2011). In a small-scale study with 35 subjects, Ewa Jówoko and her co-workers investigated the effect of 1280mg of green tea polyphenols (from a standardized GTE supplement by Olimp Sports) had on the adaptational response to a standardized 4-week strength training regimen (cf. figure 1)

Figure 1: Summary of the study design - participant characteristics, training and supplementation regimen.

If you look at the summary of the study protocol in figure 1, you may notice that there are two factors which contribute to the real-world significance of the study. Firstly, the subjects followed a semi-standardized diet (90g protein; 270g carbs; 104g fat), because they had to eat at the University's cafeteria. Secondly, the training, as well as the supplementation protocol are similar to what a real beginner would be doing in the gym, when he strives to build lean muscle tissue. On the other hand, this also means that we will probably see different (I would bet even less pronounced) results in trained athletes / advanced strength trainees with an optimized diet and a highly sophisticated supplement regimen - so bare that in mind, when you interpret the following results.

Figure 2: Changes in back squat and bench press 1-RM max and repetition max after 4-weeks of strength training with and without GTE supplement (data calculated based on Jówoko. 2011).

It should not surprise you that 4 weeks of training led to increases in squat and bench press performance. The inter-group differences, as well as the increase in maximal repetition number on the bench, however, did not reach statistical significance. In other words, what we are seeing here are effects of the exercise regimen, independent of GTE supplementation.

Figure 3: Changes in blood pH, base excess and lacate subsequent to the initial (Term I) and post (Term II) muscular endurance and max strength tests (data calculated based on Jówoko. 2011).

Similarly, the changes in blood ph, base excess and lacate subsequent to the initial (Term I) and post (Term II) muscular endurance and max strength tests (cf. figure 3), were not statistically different between groups. But if you followed the SuppVersity news lately, you will already know that blood ph is the domain of plain baking soda... so why even bother with green tea in this regards? After all its not even supposed to be a H+ buffer, but a powerful anti-oxidant, so what we should see are decreased rates of oxidation...

Figure 4: Lipid hydroxyperoxides at rest, 5min and 24h after a strength and endurance test before and after the 4-week intervention (data based on Jówoko. 2011).

And in fact, if you take a very close look at the data in figure 3, you may be able to see (I highlighted the bar for you ;-) why the title of the study, "Green tea extract supplementation gives protection against exercise-induced oxidative damage in healthy men", is not totally off: The degree of lipid peroxidation at rest(!) remained constant (within statistical margin) in the GTE group, while it increased by +27% in the non-supplemented group. In view of the non-existent differences in terms of strength or endurance gains between the groups, it is yet very questionable whether this "protective" effect is worth the 16$ (based on the price of the original supplement used in the study that is only available in Europe) it would cost to mimic the supplementation regimen used in the study - especially for someone who does meet the dietary requirements for vitamin E, which is something the study participants with their cafeteria food didn't.

Scientific fraud in the name of marketing

The results of the second study, which investigated the effects of decaffeinated green tea extract (DGE: 2x530mg per day; 800mg catechins per day, total) on body weight changes in 69 overweight subjects (sedentary males, aged 40–69 years, with BMI > 28 and < 38 kg/m²) are similarly dazzling. In their abstract, A. L. Brown and his collegues from Unilever (do I have to say anything else) summarize the results of their 6-week placebo controlled cross-over study as follows (Brown. 2011):

Despite a similar increase in estimated energy intake during intervention period 1, body weight decreased by 0.64 (SD 2.2) kg and increased by 0.53 (SD 1.9) kg in the DGT and placebo groups, respectively (P< 0.025), suggesting a protective effect of green tea catechins on weight gain.

Does not sound earth shattering, but -0.6kg weight loss does at least appear to be more desirable than +0.53kg weight gain. But even if you do not have access to the full-text (as I do) and are thus able to debunk this as a blatant manipulation of the facts (which, by the way, is the result of selecting data from the more favorable 2 weeks of the 6-week study period), the standard-deviations of 2.2kg in the DGE and the 1.9kg in the placebo group should ring an alarm. If you do have the full-text, and take a closer look at table 3 (cf. excerpt)...

Table 1: Excerpt from table 3 in Brown, 2011

... you should start sensing fraud. After all, the table clearly states that the mean body weight loss over the whole study period was -0.038kg for the placebo and -0.327kg for the decaffeinated green tea group. If you now scroll a few pages down and read the last paragraph...

The authors are all employed by Unilever Research & Development, which is a division of Unilever plc, a company which has a significant commercial interest in tea. Unilever plc provided all funding for the study.

... it should become obvious that, even in the case of something as "innocent" as green tea, you better not believe everything you hear and read about "superfood" and respective extracts on the Internet. So, instead of buying decaffeinated capped bullshit from Unilever, you better go to your local grocery store, get yourself some quality green tea and make tea-time a relaxing part of your probably hectic daily routine ;-)

Can 5 Cups of Coffee Boost Testosterone to Estrogen Ratio in Overweight Men Transiently by Almost 200%? Plus: SHBG Its Own Receptor and Its Role in Prostate & Breast Cancer

Testosterone booster in men and estrogen amplifier in women? As if there were not already enough good reasons to get your daily dose of the 'kingly' brew ;-)

You would not have to be a diligent student of the SuppVersity to know: Coffee is a truly remarkable brew. Even mainstream media has gotten wind of the multitude of beneficial effects a moderate intake of the former drink of the kings and popes can have on your health and if it was not for the authors and newscasters blind reliance on whatever the press release guys are telling them, it would probably not even have been necessary for me to broach the beneficial effects coffee can have on your metabolic health and overall well-being in posts like "Coffee - 3 Cups a Day Keep Insulin at Bay", "Pre-Workout Caffeine: Fat Liberator, Substrate Modulator, Trans-Fatty Acid Eliminator & Performance Upregulator!" and many more.

So what is it this time? What else can coffee do for you?

I guess something only few people others than SuppVersity readers will be aware of is the fact that caffeine  and therefore coffee makes a nice testosterone booster (Beavon. 2008; study was discussed briefly as part of a longer post on June 20, 2012 an mentioned previous times in other posts) -- at least if you stick to moderate doses of ~300-400 mg before a workout. So, unless you are a newbie or missed the respective news, you should not be surprised that a recent study from the Harvard School of Public Health (Wedick. 2012), which had actually been designed mainly to investigate the effects of 5x 6-ounze cups caffeinated and decaffeinated coffee (both instant coffees; brand: Nestlé’s Taster’s Choice) on serum levels of sex hormone-binding globulin (SHBG), found that the consumption of both 'real' and 'fake' (=decaffeinated) instant coffee did lead to increases in total and free testosterone and profound decreases in estradiol (bound and free).

Figure 1: Levels of SHBG, testosterone, free testosterone, estradiol, free estrogen, the testosterone to estrogen ratio and DHEA in the male participants of the study expressed relative to a caffeine abstinent control group (based on Wedick. 2012)

As the data in figure 1 goes to show these changes were unfortunately transient and the impressive +189% increase in the testosterone to estrogen ratio which occurred during the first month of treatment totally disappeared within the next four weeks. On the other hand, the effects on SHBG the scientists had expected based on the assumption that both SHBG and caffeine intake have been found to be associated with lower risk of type II diabetes in large epidemiological studies, was non-existent in the first and second 4 weeks of the study... at least in the male subjects who were all overweight, nonsmokers and habitually coffee consumers, who had been required to abstain from caffeine intake for at least 2 weeks before the study was conducted.

Figure 2: Levels of SHBG, testosterone, free testosterone, estradiol, free estrogen, the testosterone to estrogen ratio and DHEA in the female participants of the study expressed relative to a caffeine abstinent control group (based on Wedick. 2012)

If you take a look at the data from the female participants (likewise overweight non-smokers, habitual caffeine consumers and, at the beginning of the study, 'dried out'; see figure 2), a different image emerges, in the women we do in fact see a transient rise in SHBG, which goes hand in hand with a decrease in testosterone, de to which the T/E ratio drops by -36% and -54% in the groups drinking caffeinated and noncaffeinated coffee respectively. Just as in their male counterparts, the levels did go back up in the second part of the study so that all values, including the SHBG levels were back in to normal after 8 weeks (please note changes in the 20% range are irrelevant and could be due to having a meal before the test, bad sleep, whatever).

The relative data tells only part of the story

Figure 4: Absolute values of the testosterone to estrogen ratio after 4 and 8 weeks; baseline levels were 16.2, 15.8, 18.2 in the caffeinated coffee, decaffeinated coffee and control group respectively. The data clearly shows: Coffee needs a PCT ;-)

If we do now take a closer look at the actual data and discard the comparison to the control group the scientists the picture becomes even more complex. After all the data in figure 4 clearly indicates that we are dealing with a combined effect here. It is correct that the ingestion of the caffeinated beverage had pronounced effects on the T/E ratio especially in the male participants, what the data in figure 1 does yet not tell you is the fact that this effect was also so pronounced, because simply stopping to drink caffeine reduced the T/E ratio from 18.1 to 8.4, i.e. by 54%(!).

Now this certainly reduces the effect size, but it does not totally negate the effect. After all the 'real' coffee drinkers (w/ caffeine) did still increase their T/E ratio from 16.2 to 24.2 -- a certainly likewise noteworthy increase of +29% that is however still far away from the exorbitant +189% increase compared to the poor guys who did not just lose their coffee, but also their virility.

So what does this tell use?

How cares about SHBG anyways? You should! After all there is relatively conclusive evidence that normal (not exorbitantly high!) SHGB levels have a protective effect against breast cancer in women and mechanistic evidence that they increase the risk of prostate cancer in men. In both cases SHBG acts independently via the largely ignored SHBG receptor that modulates the action of estrogens. Co-activation of SHBG and estrogen receptor in the prostate induces similar effect on prostate specific antigen secretion as DHT (Nakhla. 1997). Since estrogen alone does not have this effect, it is no wonder that stinging nettle root (Urtica dioica), with its SHGB inhibiting effect is a viable tool in the treatment of benign prostatic hyperplasia (Hryb. 1995). In the female breast, on the other hand, SHBG seems to " trigger a 'biologic' anti-estrogenic pathway" (Fortunati. 1999) and does therefore exert anti-instead of pro-carcinogenic effects.

I guess there are more than just the following three lessons to learn from this study, but at the moment these appear to be the most important ones for me:

1. The beneficial effects habitual coffee intake has on type II diabetes risk are, contrary to the scientists hypothesis, not mediated by its effect on SHBG.
2. In overweight men caffeine has a very shortlived beneficial effect on testosterone and the testosterone to estrogen ratio. After 4 weeks the levels do yet return to baseline, so this cannot explain the long-term benefits of habitual caffeine consumption either (maybe you should cycle caffeine instead of testosterone booster < I am just kidding ;-).
3. In overweight women, there is a similar, yet negative effect on testosterone levels, which is likewise transient and lasts less than 8 weeks. 
4. The caffeine ads to the 'pro-testosterone' effects, but even decaffeinated coffee has some effects.
5. Stopping "cold turkey" is not a good idea, when you are "on caffeine"

Now, what is important here is that we are dealing with overweight individuals, in whom the endocrine millieu is usually off. In particular, men tend to have reduced, women tend to have increased androgen levels (think PCOS). The effects we see after short-term withdrawal and the subsequent consumption of a non-negligible amount of 5 cups of coffee everyday could actually have corrective effects on the endocrine milieu, of which both, men and women could benefit, if they would last for more than 4-6 weeks. The detrimental effects of stopping, on the other hand, could be due to the sudden absence of the benefits of caffeine.

Regardless of whether you stop or start drinking coffeine, the endocrine "disturbances" are relatively short-lived and only further testimony to the fact that our bodies will always try to find a new "steady state" in what they consider normal.

Bottom line: There are a myriad of good reasons to drink coffee, getting more manly or more feminine is yet not one of them. Disappointed? Well, on the other hand this means coffee is no endocrine disruptor - and at least in this overweight population it seems to have a marginally beneficial baseline effects (thus the detrimental effects of abstinence).

References:

• Beaven CM, Hopkins WG, Hansen KT, Wood MR, Cronin JB, Lowe TE. Dose effect of caffeine on testosterone and cortisol responses to resistance exercise. Int J Sport Nutr Exerc Metab. 2008 Apr;18(2):131-41. 
• Fortunati N, Becchis M, Catalano MG, Comba A, Ferrera P, Raineri M, Berta L, Frairia R. Sex hormone-binding globulin, its membrane receptor, and breast cancer: a new approach to the modulation of estradiol action in neoplastic cells. J Steroid Biochem Mol Biol. 1999 Apr-Jun;69(1-6):473-9.
• Hryb DJ, Khan MS, Romas NA, Rosner W. The effect of extracts of the roots of the stinging nettle (Urtica dioica) on the interaction of SHBG with its receptor on human prostatic membranes. Planta Med. 1995 Feb;61(1):31-2.
• Nakhla AM, Romas NA, Rosner W. Estradiol activates the prostate androgen receptor and prostate-specific antigen secretion through the intermediacy of sex hormone-binding globulin. J Biol Chem. 1997 Mar 14;272(11):6838-41.
• Wedick NM, Mantzoros CS, Ding EL, Brennan AM, Rosner B, Rimm EB, Hu FB, van Dam RM. The effects of caffeinated and decaffeinated coffee on sex hormone-binding globulin and endogenous sex hormone levels: a randomized controlled trial. Nutr J. 2012 Oct 19;11(1):86.

Coffee, Tea, Cacao, Caffeinated Sodas & Breast Cancer: 5+ Cups/Day?! Study & Meta-Analysis Show, It May Take More Coffee Than Previously Thought to Ward Off Breast Cancer

While you don't have to bath in coffee, one cup per day is probably not enough to protect your mammary glands.

Initially today's SuppVersity post was just about coffee and breast cancer risk. Today, a couple of days and a hand full of news on other interesting papers that are piling up by dozens in my archive, I found that the paper has proliferated ;-o

Well, not exactly, but in conjunction with a recent meta-analysis on the potential anti-breast-cancer effects of coffee today's news certainly covers data from almost 380,000 women world-wide and will thus probably yield somewhat more reliable data on whatever relation may exist between a woman's coffee / caffeine consumption and her risk of developing breast cancer.

It takes Canadian women at least 5 cups of coffee to elicit significant reductions in breast cancer risk

Against that background, both the detailed 7-item sub-analysis of the data from the Women’s Diet and Health Study and the unique inclusion of information on the cytochrome P450 1A2 (CYP1A2; the enzyme that's responsible for the metabolism of caffeine) gene variant of the 25 to 74 year old women distinguish the soon-to-be-published epidemiological study by Elizabeth C. Lowcock and her Canadian (resident) who found that there is no general association with coffee and caffeine consumption on the one, and breast cancer risk on the other hand.

"[H]owever, a significant reduction in risk was observed with the highest category of coffee consumption [≥5 cups per day vs. never, multivariate-adjusted odds ratio (MVOR)=0.71, 95% confidence interval (CI): 0.51, 0.98]." (Lowcock. 2013)

Interestingly, the ~30% reduction in breast cancer risk the scientists observed in their cohort of Ontarian women, did not depend on the gene variant of the aforementioned caffeine metabolizing enzyme from the cytochrome P450 enzyme cascade. coffee consumption, but not total caffeine" (Lowcock. 2013) that's associated with a reduced risk of both estrogen receptor positive and post-menopausal breast cancers.

Figure 1: Multivariate-adjusted odds ratios for breast cancer and coffee, decaffeinated coffee and caffeine intake w/out correction for CYP1A2 (rs762551) genotype (Lowcock. 2013)

In conjunction with the actual data from the 7-item analysis, this observation supports the scientists hypothesis that it is "coffee consumption, but not total caffeine" (Lowcock. 2013) that's associated with a reduced risk of both estrogen receptor positive and post-menopausal breast cancers.

If that is true, i.e. if it's not the main active ingredient caffeine, but one of or the complete spectrum of polyphenols the dark brew has to offer, it seems logical that such an exuberant amount of coffee is necessary to benefit from the purported protective effects (remember we are still talking about associations of consumption and breast cancer incidence - not mechanisms) of coffee. Why? Well, despite the fact that a comparison on a mere weight-to-weight ratio is obviously overtly simplistic, the amount of whatever flavenoid or other ingredient may turn out to be responsible for the anti-cancer effect is almost certainly at least one, if not several magnitudes smaller than those 100-200mg of caffeine your "average" (whatever that may be today) cup of coffee has to offer.

2% risk reduction per two cups? Looks like more was really better.

The notion that "more helps more" is indeed supported by another a meta-analysis of 37 international studies, Wenjie Jiang, Yili Wu and Xiubo Jiang from the Medical College of Qingdao University in Shandong have conducted (Jiian. 2013).

Suggested read: "Only 'Real', Yet Not Decaffeinated Instant Coffee Increases Fatty Acid Oxidation. Plus: Revisited, Caffeine's Dose-Dependent Effect on the Exercise Induced Changes to the ratio of Testosterone to Cortisol" (read more)

According to the study, which is going to find it's way into one of the next issues of Gynecologic Oncology, the collective data of 966,263 study participants (59,018 breast cancer cases) does not warrant the conclusion that either coffee or caffeine consumption (yes vs. no) is associated with a significant reduction in breast cancer risk:

• coffee -- 3% risk reduction, p = 0.09
• decaffeinated coffee -- 2% risk reduction p = 0.55 
• caffeine - 1% risk reduction,  p = 0.73

In fact, the p-value, i.e. the probability that a result is mere coincidence, passes the magic p < 0.05 (meaning there is a <5% chance of the observed association being mere coincidence) hurdle only in postmenopausal coffee concessionaires, whose risk of developing breast cancer is 6% lower than that of their non-coffee guzzling peers.

What's particularly intriguing, though, is the fact that Jiang, Wu & Jiang found a linear dose-response relationship for breast cancer risk with coffee and caffeine, with

"the risk of breast cancer decreas[ing] by 2% (P=0.05) for every 2 cups/day increment in coffee intake, and 1% (P= 0.52) for every 200 mg/day increment in caffeine intake, respectively." (Jiang. 2013)

If we do the math this yield a 10% reduction in breast cancer risk for the 5 cups which gave the Canadian women a 30% edge over their non-coffee drinking peers.

In view of the fact that the number of people consuming this amount of coffee on a daily base (3% in the Women's Diet & Health Study) is in epidemiological terms comparatively low, the "small" deviation of 20% is nothing that would negate the existence of a surprisingly profound protective effect of coffee on the development of breast cancer.

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Bottom line: I don't want to be a spoilsport, but as a versed SuppVersity reader you should by now be aware that anything beyond 400-500mg of caffeine (for a woman, for a man maybe 500-600mg) can produce a couple of nasty heart and central nervous system related side effects in view of which the regular / chronic consumption of more than 5 cups of coffee is nothing I would suggest as a means of cancer protection. And since the currently available data does not confirm similar beneficial effects for decaffeinated coffee (see figure 1 red button for likely explanations), you should consider different means of breast cancer protection. Which means that would be? Well, ...

Even one cup of hot chocolate per week could help reduce your risk of developing breast cancer by 15% (learn more about the health effects of cacao & chocolate)

• cut your intake of caffeinated soft-drinks to zero and thus reduce your breast cancer risk (compared to drinking 2 cans per day) by 24% or a statistically hardly significant, but still worth mentioning -7% vs. consuming only one can per week (Lowcock. 2013)
• drink some black tea for a change, and achieve a 13% reduction in breast cancer risk with 3-5 cups per day (Lowcock. 2013)
• never pass on a delicious cup of cacao, even one cup of hot chocolate per week can decrease your breast cancer risk (due to the low number of cacao drinkers the -15% reduction is yet not significant, Lowcock. 2013)

• lose weight and visceral fat to avoid the +107% increase in breast cancer risk non-hispanic white women with a BMI >30kg/m² have compared to their non-obese fellow females (Connor. 2013)

If you work out and stick to a whole foods diet, that's about as much as you can do for the health of your mammary glands. Well,... maybe aside from taking synthetic estrogen and progestin combos to battle the symptoms of menopause (read more about this in the SuppVersity Facebook news).

References:

• Connor AE, Baumgartner RN, Pinkston C, Baumgartner KB. Obesity and Risk of Breast Cancer Mortality in Hispanic and Non-Hispanic White Women: The New Mexico Women's Health Study. J Womens Health (Larchmt). 2013 Mar 26.
• Jiang W, Wu Y, Jiang X. Coffee and caffeine intake and breast cancer risk: An updated dose-response meta-analysis of 37 published studies. Gynecol Oncol. 2013 Mar 24.
• Lowcock EC, Cotterchio M, Anderson LN, Boucher BA, El-Sohemy A. High Coffee Intake, but Not Caffeine, is Associated with Reduced Estrogen Receptor Negative and Postmenopausal Breast Cancer Risk with No Effect Modification by CYP1A2 Genotype. Nutr Cancer. 2013 Apr;65(3):398-409.

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.