-20% Reduction in Serum Testosterone by 5 Cups of Green Tea. Endocrine Effects Depend on Catechin Composition.

Image 1: Another SuperFood gone bad? More than 2-3 cups of green tea could do more harm than good to health-conscious male tea-consumers.

While I obviously do not know whether you have come in contact with the rumors surrounding the effects of green tea extract (GTE) on the male reproductive system, I assume that many of you (despite the fact that this is obviously not necessary if you read the SuppVersity news everyday ;-) will be active on one of the various health and fitness related bulletin-boards, where - and here I am certain - the issue of reduced testosterone levels from GTE consumption has certainly been addressed at some point. According to a recent study, published in the September issue Indian Journal of Experimental Biology (Chandra. 2011), your favorite anti-oxidant fat burner Camellia sinensis L., in other words, green tea, has in fact to be counted among those therapeutic agents that despite having been used since ancient times, are not as safe as many customers want to believe.

Figure 1: Molecular structure of the four major green tea catechins (from Kao. 2000)

Did you know that a study from the year 2000 by Kao et al. (Kao. 2000) established a differential effect of green tea catechins (cf. fig. 1) on serum testosterone levels of Sprague Dawley (SD), as well as lean (LZ) and obese Zucker (OZ) rats? While EGCG (and ECG) potently suppressed serum testosterone levels (-69% in SD; -72% in LZ; -69% in OZ), the administration of isolated Epicatechin (EC) and Epigallocatechin (EGC) at a dose of 85 mg/kg BW (human equivalent: 14mg/kg) resulted in a statistically significant increase in testosterone levels of +24% (EC) and +31%, respectively.

In view of the fact that a 2006 analysis of 19 commercially available green tea extracts (Seeram. 2006) revealed that major differences in terms of total catechin content and ratios, the individual effect of "your" green tea caps may be either beneficial or detrimental to your testosterone levels depending on the ratio of (EC+EGC)/(ECG+EGCG) - where a higher amount of the pro-testostosterone fraction, i.e. EC + EGC would obviously be preferable.

According to the results of Amar K. Chandra and his colleagues from Calcutta and West Bengal, green tea belongs to the ranks of plants, such as Neem (Azadirachta indica), Tulsi (Ocimum sanctum) and other agents previously mentioned here at the SuppVersity, all of which have conclusively been shown to hamper reproductive functions and that despite the fact that the neuroprotective, cytotoxic and antioxidant effects of Camellia sinensis L. have been well-established.

Figure 2: Reduction in sperm count after 26 days of consumption of green tea equivalent to 5, 10 or 20 cups of green tea (data calculated based on Chandra. 2011)

As the data in figure 2 goes to show, in the course of 26 days, even the consumption of the equivalent of 5 cups of green tea lead to a statistically significant -2% reduction in sperm count in the gonads of the adult rats who were orally administered with standardized doses green tea after it had been steeped for 15 minutes in 100ml of boiling water, then cooled to room temperature and combined with a second infusion from the same 2.5g of green tea, the catechin composition of which I plotted in figure 3.

Figure 3: Catechin composition and pro- to anti-testosterone ratio of the green tea that was used in the study (Chandra. 2011)

The catechin composition of the specific green tea that was used in the study (the green tea came from the Institute of Himilayan Bioresource Technology) is, as you know from my elaborations on the Kao study in the red "Did you know"-box, probably the determining factor for its effect on the rats testosterone levels. Judged by what I called the pro- to anti-testosterone ratio of 0.47, i.e. the ratio of Epicatechin (EC) + Epigallocatechin (EGC), which increased testosterone in the Kao study, to Epicatechin-3-Gallate (ECG) + Epigallocatechin-3-Gallate (EGCG), which decreased testosterone in the Kao study, the overall effect of the green tea on the testosterone levels of the rats should be negative - and in fact, what Chandra et al. found was a decrease in serum testosterone levels in the "GTE treated groups of animals as compared to their respective control", of which the scientists speculate that it was "due to the impaired synthesis of testosterone."

Figure 4: Reduction in serum testosterone after 26 days of consumption of green tea equivalent to 5, 10 or 20 cups of green tea (data calculated based on Chandra. 2011)

These results also shed a different light on the recently reported "anti-obesity" effect of green tea. After all, the lack of androgens could be an alternative explanation for the GTE-induced 7-20% reduction in body weight Pea et al. observed in their 2011 rodent study and the reduced weight gain (-10% and -14% in the 10 and 20 cup groups, respectively) observed in the study at hand.

Weight loss or lack of weight gain, reduced testosterone, increased LH and all the other negative side effects aside, I would be surprised if low to moderate green tea consumption (2-3cups max.) would actually reduce your chance of conception, hamper your gains in the gym or even induce testicular failure. After all, neither Japan nor China or the other Asian Countries, the inhabitants of which have been having their well-deserved daily cup of (green-)tea for centuries, now, seem to have rampant fertility issues ;-)

Chocolicious Statin: One Week "on" 100g/day of 70% Dark Chocolate Improves Cholesterol Profile and Reduces Waist Circumference in "Skinny Fat" Women

With the average German eating 9-10kg of chocolate per year we should be pretty heart healthy... well, if more than 10g of those were dark chocolate, I suppose.

You know what? I am pretty enervated by the reverberations of the notorious "chocolate makes Nobel Laureates" study. Even now, month after the publication, the media hype and the head-shaking on part of anyone who does have the slightest idea of the difference between association and causation, it's still all over the place.

On my part this has lead to a "desensitization" with respect to the word "chocoloate" in medical journals, so that I had almost missed this ground-braking study from the Department of Neuroscience at the University of Tor Vergata in Rome, the National Institute for Mediterranean Diet and Nutrigenomic in Cosenza and the UOS of Pharmacology, Department of Pharmacology at the University Magna Graecia,Roccelletta di Borgia in Catanzaro, Italy (di Renzo. 2013)

Chocolate for the skinny fat

As if it was not already enough that this is a "non-Nobel-Laureate-infected" study on chocolate consumption, it's also study on skinny fats: 15 women in the age of 20-40 years with a normal BMI, but high total body fat mass (FM) percentage (FM% > 30%) and significantly higher values of proinflammatory cytokines, such as IL-1, IL-6, IL-8 and TNF-α. SuppVersity reader what else can you ask for?

Well, ok.... probably you could ask what the study was all about. So, the intervention was pretty simple:After a dark-chocolate-free (DC) washout period, the subjects received 100g of dark chocolate per day for 7-days (50g in the morning another 50g as an afternoon snack or at dinner).The dark chocolate contained (only) 70% cocoa and was provided as an unrestricted gift from Valrhona, Tain l’Hermitage, France. Of the 70% cacao in it, 42.5% were cacao butter with a fatty acid composition of 64.6% saturated fats, 34% monounsaturated fats and only 4.4% PUFA. The sugar in the chocolate was almost exclusively saccharose.

Chronic diet = skinny fat!? (learn more)

Did you know? In previous studies, di Renzo et al. found that 10% of the Italian women fall into the "skinny fat", or as they put it "normal-weight obese" category. These women had similar increased cardiovascular disease (CVD) risk indexes values, as their pre-obese peers, but did not manifest the metabolic syndrome, despite a cluster of metabolic and genetic features associated with increased CV mortality (di Renzo. 2006, 2009, 2010; Marques-Vidal. 2010).

Moreover, the chocolate contained 2% polyphenols, and 0.7% theobromine, as well as 444mg/kg naturally occurring catechins, 908mg/kg epicatechin and 20, 20 and 40mg/kg epigallocatechin gallate epicatechin gallate, Epigallocatechin, respectively.

Improved blood lipids, improved body composition, improved....

The main outcomes of the study were the changes in body composition (DXA), blood pressure, anthropometric measurements, biochemical parameters and plasma levels of some cytokines within the 7-day intervention period.

Figure 1: Changes in lipid and glucose metabolism during the 7-day chocolate intervention (di Renzo. 2013)

And as you can see in figure 1, the results were ambiguous. We have the great and statistical signifcant improvement on the cholesterol side of things, as well as a reduction in specific markers of infallamtion, i.e. IL-6 (-33%), TNF-α (-19%) and IL-1Ra (-33%) and a 1cm reduction in waist circumferene. On the other hand, we do also see increases in fasting insulin and insulin resistance, which did not reach statistical significance, but remind me of the inverse effects on lipid and glucose metabolism we see with so many other agents with cholesterol lowering effects.

Still if we rely on statistics, the overall effects is a beneficial one, but...

There is another string attached, though, due to which I still cannot wholeheartedly recommend to add those 100g of chocolate to your diet, because the scientists did not have the funds for a control group... that's a major bummer. After all, we don't really know if the changes were not brought about by the standardization of the diet, which took place at the beginning of the DC abstinence period and of which the authors write:

Did you know? In another study 40g of dark chocolate consumed on a daily basis for 2 weeks were able to reduced the urinary excretion of the stress hormone cortisol and catecholamines and partially normalized stress-related differences in energy metabolism in 30 human subjects, who were classified in low and high anxiety traits using validated psychological questionnaires. (Martin. 2009)

"Total daily energy content of the diet was determined on an individual basis, calculated using De Lorenzo et al. prediction equation for the Italian population. Initial caloric levels were adjusted, when necessary, to maintain the body weight. All subjects received about 1700 kilocalories/day. The recommended composition of the dietary regimen was as follows: carbohydrates, 55% to 60%; proteins, 15% to 20% (of which about 50% was comprised of vegetable proteins); total fat, 25% (saturated fat acids (SFA), less than 10%, and cholesterol consumption, less than 300 mg per day), and 30 g of fibre.

[...] The composition of the diet in terms of foods and food combinations was planned to obtain an animal to vegetable protein ratio as close to 1:1 as possible. The Italian Recommended Dietary Allowances were incorporated to ensure proper vitamin and mineral intake."

Otherwise, the subjects were were advised "not to consume any other chocolate for the duration of the study" and to make "no further changes to their diet and lifestyle habits" (di Renzo. 2013).

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Bottom line: I do not question the value of adding a chunk of dark chocolate to your diet from now to then and I believe the beneficial effects on your blood lipids is well-established enough to even suggest the supplementation with "pure" chocolate (90%+) just for this porpose.

The EDC Program - Exercise + Diet + Chocolate (learn more)

The question is yet, do you need that? If you are skinny fat, probably. If you work out regularly and have your diet in check, unlikely. So, why would you want to run the risk of being among those of the ladies in the study at hand who must have experienced pretty extreme elevations in fasting insulin. If we were talking about something that happened across the board to all of them, the data would be statistical significant. The way it is, my best bet is that the increase in circulating free fattty acids in response to the combination of catechins + theobromine may be to blame. And this response can very well be very different from one individual to the other. But who knows, maybe it was just the dietary switch (?) to an up to 60% carbohydrate diet that was to blame for these results!?

References:

• Di Renzo L, Bigioni M, Bottini FG, Del Gobbo V, Premrov MG, Cianci R, De Lorenzo A. Normal Weight Obese syndrome: role of single nucleotide polymorphism of IL-1 5Ralpha and MTHFR 677C-->T genes in the relationship between body composition and resting metabolic rate. Eur Rev Med Pharmacol Sci. 2006 Sep-Oct;10(5):235-45. 
• Di Renzo L, Gloria-Bottini F, Saccucci P, Bigioni M, Abenavoli L, Gasbarrini G, De Lorenzo A. Role of interleukin-15 receptor alpha polymorphisms in normal weight obese syndrome. Int J Immunopathol Pharmacol. 2009 Jan-Mar;22(1):105-13.
• Di Renzo L, Galvano F, Orlandi C, Bianchi A, Di Giacomo C, La Fauci L, Acquaviva R, De Lorenzo A. Oxidative stress in normal-weight obese syndrome. Obesity (Silver Spring). 2010 Nov;18(11):2125-30.
• Marques-Vidal P, Pécoud A, Hayoz D, Paccaud F, Mooser V, Waeber G, Vollenweider P. Normal weight obesity: relationship with lipids, glycaemic status, liver enzymes and inflammation. Nutr Metab Cardiovasc Dis. 2010 Nov;20(9):669-75.