Green Tea Lipids + Statins, PWO CHO + Glycogen, Visceral Fat, Heart Health + Anthrax - Research Update July '17

Matcha releases more antioxidants than tea leaves (Fujioka. 2016).

Only recently, you've read the "Caffeine June 2017 Research Update" [(re-)read it] here at the SuppVersity. Some of the effects of green tea have thus already been discussed. After all, caffeine is one of the health-relevant ingredients of tea; it is, however, not the most important one.

As Yuan Fen et al. explain in their latest meta-analysis of the effects of green tea on blood lipids, tea can be classified as green tea, oolong tea or black tea depending on the manufacturing process" (Fen 2017). What exactly it is that mediates the various health benefits of tea (inflammation, hypertension/heart disease, and cancer | Serafini 2011) and their potency may thus differ slightly from tea to tea.

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For example, "green tea is abundant with kaempferol glycosides, while oolong tea contains more quercetin and myricetin glycosides and black tea is rich in quercetin glycosides" (Fen 2017). Most importantly, however, teas contain substances we call catechins, e.g. epigallocatechin gallate (EGCG), epicatechin gallate (ECG), epigallocatechin (EGC), and epicatechin (EC). EGCG is considered to be is the major and functional component (Fen 2017). Accordingly, hitherto published studies tested or ascribed the health effects of green tea to the high relative amount of EGCG. I have thus chosen both studies using real tea and EGCG/catechin supplements for this SuppVersity Research Update:

• Green tea improves your blood lipids like a statin, but without the side-effect-prone mechanism of blocking cholesterol completely (Fen 2017) -- The effects of green tea consumption on lipid metabolism in people with overweight or obesity was the research interest of the previously cited study by Fen et al. in "Molecular Nutrition & Food Research". Based on 21 published RCTs, the scientists calculated that ...

  

  Figure 1: No clear effect on HDL was observed (Fen 2017).

  "[...] green tea significantly decreased plasma total cholesterol (TC) and low-density lipoprotein cholesterol (LDL) levels in overweight or obese people[, in form of a] 3.38mg/dl [reduction] for TC (95% CI: -6.42, -0.33mg/dl) and -5.29mg/dl [reduction] for LDL (95% CI: -7.92, -2.66mg/dl), respectively" (Fen 2017).

  That sounds great, but the absolute change in LDL is small in comparison to the average statin, which achieves reductions of 69.6 mg/dl (Law 2003).

Warning! EGCG may mess with the efficacy of your statins (and other medications): It's important to note, that EGCG acutely reduces the pharmacokinetics of statins. This has been proven only recently (Kim 2017) for rosuvastatin in healthy volunteers, whose systemic exposure to the drug was reduced by a whopping 19% when EGCG and rosuvastatin were co-administered only once. Interestingly enough, though, two weeks of chronic EGCG supplementation abolished this inhibitory effect. Green tea does that by interacting with a range of intestinal and hepatic organic anion transport peptides (OATPs) and we're yet far from understanding all its drug interactions. Proven have been the previously mentioned interaction with rosuvastatin, as well as interactions with the blood pressure medication (beta blocker) nadolol, and another statin, namely simvastatin, where it had, paradoxically, opposing effects and increased the plasma concentration by inhibiting both, intestinal CYP3A4 and P-gp and hepatic OATP1B1 (Werba 2015).

And there's more. In rodents on high cholesterol diets, scientists from the Hebrew University in Jerusalem have recently been able to demonstrate that the effect of green tea polyphenols on bile acid will overload your livers ability to get rid of cholesterol and thus promote non-alcoholic fatty liver disease (Tirosh 2017) - a phenomenon that has already been observed in human beings, too.

• Accordingly, people who actually need statin drugs because they have a genetically high risk of heart disease would be ill advised to try and replace their medications with green tea - not just, but also because "green tea's effect on plasma TG and HDL must be further evaluated by additional high-quality and large-scale RCTs" (Fen 2017) - also to answer, among others, the following question.
  • the differential effects of caffeinated and decaffeinated green tea on triglycerides (↕ for regular ↘ for decaffeinated green tea)
  • differences in health effects in healthy overweight or obese individuals vs. unhealthy overweight or obese individuals (in whom the scientists' subgroup analyses, for example, showed sign. reductions in triglycerides that were not observed in healthy subjects)
  • age-effects that couldn't be analyzed in the current meta-analysis of studies in which people from all age groups (from children to the elderly) participated
  • the seriousness and root cause of side effects, which were transient, but were still reported in four of the twenty-one trials
  For (lean and obese) individuals who are interested in overall heart health and don't have a genetically determined increased risk of heart disease, the 2-4 cups of green tea (or 300-1500mg green tea extract) the subjects in the 21 RCTs certainly are the better choice for cholesterol control - after all, the reduction in total (TC) and low-density cholesterol/lipoproteins (LDL) occurs in the absence of headaches, flushing, weakened and impaired skeletal muscle, diabetes, and liver injury - all repeatedly reported side effects of statin therapy (Mancini 2011; Chaipichit 2015; Castro 2016).

600mg/day Anything Beyond That and EGCG May Mess W/ Your Liver Health! Scientists Propose 300mg/day Limit for EGCS in Food Supplements (read the SuppVersity Facebook News Post from July 2nd, 2017). While evidence that the real deal, i.e. green tea can damage your liver, things look different for supplements with isolated catechins, esp. EGCG.

Dekant et al. recently reviewed the existing literature and came to the conclusion that EGCG has the potential to induce hepatic damage. Based on the finding that "[i]n clinical intervention studies, liver effects were not observed after intakes below 600mg EGCG/person/day," the researchers propose a "tolerable upper intake level of 300mg EGCG/person/day" which would give you "a twofold safety margin" (Dekant 2017).

• New study questions previously reported beneficial effects of green tea on post-exercise glycogen resynthesis, but... (Tsai 2017) -- You will remember my article from last October in which I outlined that "Green Tea Extract Reduces the Amount of Insulin You Need to Store Your PWO Carbs by ~20%" (read it). A recent study in the British Journal of Nutrition does now suggest that these effects may at least be dose-dependent.
  
  Unlike the previously cited study by Martin et al. (2016) used 3x350mg of green tea extract (GTE) for one week, Tsai et al. administered a significantly lower dose of GTE (500 mg/d) for 8 weeks. Furthermore, the scientists used a low-intensity workout and a carbohydrate-enriched meal, instead of a graded exercise and 75g of pure glucose as post-workout (PWO) nutrition.
  

  

  Figure 2: While the study did not confirm the beneficial effects on PWO glucose metabolism, it found a sign. reduced PWO RER (a), i.e. ratio of CHO:FAT oxidation, due to higher fat oxidation rates w/ GTE (Tsai 2017).

  In all honesty, it is thus not surprising that Tsai et al. observed only one significant benefit of GTE supplementation: it increased exercise-induced muscle GLUT type 4 (GLUT4) protein content of the vastus lateralis and the energy reliance on fat oxidation compared with the placebo trial (P<0·05). That there were no differences in blood glucose and insulin responses between the two trials may simply be a function of the comparatively slow rise in blood glucose in response to the test meal with a GI of "only" 76.6 (23.4% lower than glucose).
• Even on a normal diet, green tea prevents visceral adiposity (Raso 2017) -- While we do have dozens of studies showing that green tea alleviates the (visceral) body fat accumulation in response to unhealthy, hypercaloric diets, the latest rodent study by Raso et al. is the first study to investigated the effects of administering green tea as the main source of hydration on visceral fat accumulation in the long run - in human terms 45 years!
  

  

  Figure 3: Changes in relative (per kg body weight) and absolute visceral fat over the course of what would be 45 years in human beings with either water or green tea as the main source of hydration (Raso 2017).

  And the results are, as you can see in Figure 3, quite significant: While all animals, which were young at the beginning of the study, showed a sign. increase in weight and visceral fat over the course of the 18-week study, the visceral fat gains proportional to the weight of the animals were different between the groups. In that, the green tea group had a significantly smaller gain in visceral fat compared to body weight, resulting in a smaller area of visceral fat per kilogram body weight at the end of the experiment compared to the control group (p < 0.01).

Table 1: Research overview (Oz 2017 | free full text)

SuppVersity Suggested Read: "Chronic Inflam-matory Diseases and Green Tea Polyphenols" (free full-text). It is well known that green tea polyphenols (GrTPs) are potent antioxidants with important roles in regulating vital signaling pathways. This review summarizes how they act on transcription nuclear factor-kappa B and related proteins to ameliorate the surge of inflammatory markers like cytokines and production ofcyclooxygenase-2.

• Anthrax? Green tea can kill Bacillus anthracis the etiologic agent of the infamous infective disease anthrax that has been used to threaten people and governments by terrorists before (Falcinelli 2017) -- 10 days, that's the time that you have left on earth if you're infected with anthrax spores, spores that can infect you if you touch infected meat or breath in anthrax spores. The corresponding ease of infection is one the reasons that politicians and researchers fear the possible future use of B. anthracis as a bioterrorism agent.
  

  

  Figure 4: Green tea inhibits growth and kills Bacillus anthracis in Luria Broth. CFU/ml of bacilli grown for 4 h in the presence of 10% black tea or 10% green tea. n = 3. p = 0.08, black tea. *p < 0.01, green tea (Falcinelli 2017)

  This fear has resulted in an impetus to develop more effective protective measures and therapeutics. In their latest study, Falcinelli, et al. show that green tea inhibits the growth of B. anthracis - albeit yet only in vitro.
  
  As you probably already expected, it's epigallocatechin-3-gallate (EGCG) that was shown to be responsible for this activity. Yet even though EGCG was clearly bactericidal against both the attenuated B. anthracis ANR and the virulent, encapsulated strain B. anthracis Ames strain, future studies will have to show if and how green tea and EGCG can be used in human beings to prevent or battle anthrax infections... which reminds me to remind you, that GTE has also been shown to be a useful natural disinfectant able to limit enteric viral contaminations conveyed by food and food-contact surface (Randazzo 2017).

Can green tea "fix" Alzheimer's? Latest review of the efficacy of Epigallocatechin-3-gallate (EGCG from green tea) in the treatment of Alzheimer’s disease says that even though "in recent years, natural compounds, due their antioxidants and anti-inflammatory properties have been largely studied and identified as promising agents for the prevention and treatment of neurodegenerative diseases, including AD," the authors highlight that the "promising results" come exclusively from "pre-clinical" studies, so that "drawn clinical trials are extremely needed" (Cascella 2017) before we can tell how useful EGCG is whether it has preventive effects, only or can also be used to ameliorate if not curative Alzheimer's when someone is already experiencing symptoms.

• Part of the heart health benefits of green tea are not about EGCG and green tea extracts don't help with blood flow either, while real tea does (Lorenz 2017) -- In a randomized crossover study, a single dose of 200 mg EGCG was applied in three different formulas (as green tea beverage, green tea extract (GTE), and isolated EGCG) to 50 healthy men. Flow-mediated dilation (FMD) and endothelial-independent nitro-mediated dilation (NMD) was measured before and two hours after ingestion. Plasma levels of tea compounds were determined after each intervention and correlated with FMD.
  
  

  

  Figure 5: Only green tea increased flow-mediated dilation (FMD). Subjects consumed 200 mg of EGCG as isolated EGCG, GTE, or green tea after fasting overnight. An equal volume of hot water served as control. Green tea significantly increased FMD compared to GTE, EGCG, and water as control. Water slightly decreased FMD, whereas EGCG and GTE had little effects. Data are means ± SEM from n = 50 subjects. All p-values by repeated measures ANOVA followed by post hoc Bonferroni (Lorenz 2017).

  FMD significantly improved after consumption of green tea containing 200 mg EGCG (p < 0.01). However, GTE and EGCG had no significant effect on FMD. NMD did not significantly differ between interventions. EGCG plasma levels were highest after administration of EGCG and lowest after consumption of green tea.
  
  Even though the plasma levels of caffeine increased after green tea consumption, caffeine is not exactly the most likely among the various candidate ingredients that could take EGCG's place as an active ingredient responsible for green tea's (drink) ability to improve flow-mediated dilation. After all, previous studies suggest that coffee rather decreases than increases FMD (Papamichael 2005). Since similar effects have been observed by Heiss et al. in 2007 for a high-flavanol cocoa drink, other phenolic constituents of green tea, which obviously cannot be found in green tea extracts are much likelier candidates.

Hot or not? That could be a matter of health or ah... well almost death ;-) Learn why in my previous article "To Boil or Not to Boil? What's Going to Make Your Tea the Healthiest? Recent Study: It Depends on the Type of Tea"

How do I prepare the healthiest green tea? Now that you've learned that a DIY water-extract from green tea is better than commercially available extracts in pills or capsules (at least for FMD), this question is probably preying on your minds.

The answer to this important question comes from a study that will not be officially published before November this year. A study that shows that increasing the extraction temperature will also increase the polyphenol content of your tea. Thi sin turn enhances not just the antioxidant activity of the brew, it will also boost its ability to inhibit α-glucosidase and α-amylase, in vitro. In vivo, however, green tea steeped at 60°C had significantly stronger glucose uptake inhibitory activity (p<0.05) than green tea that was prepared at 100°C.

The answer to the previously raised question "Hot to brew the perfect tea?" is thus both, context- and, as previously discussed research suggested, also type-dependent | Comment.

References:

• Chaipichit, Nataporn, et al. "Statin adverse effects: patients’ experiences and laboratory monitoring of muscle and liver injuries." International Journal of Clinical Pharmacy 37.2 (2015): 355-364.
• Cascella, Marco, et al. "The efficacy of Epigallocatechin-3-gallate (green tea) in the treatment of Alzheimer’s disease: an overview of pre-clinical studies and translational perspectives in clinical practice." Infectious Agents and Cancer 12.1 (2017): 36.
• Castro, M. Regina, et al. "Statin use, diabetes incidence and overall mortality in normoglycemic and impaired fasting glucose patients." Journal of general internal medicine 31.5 (2016): 502-508.
• Dekant, et al. "Safety assessment of green tea based beverages and dried green tea extracts as nutritional supplements." Toxicol Lett. 2017 Jun 24. pii: S0378-4274(17)30233-3. doi: 10.1016/j.toxlet.2017.06.008. [Epub ahead of print]
• Falcinelli, S.D. et al. "Green tea and epigallocatechin-3-gallate are bactericidal against Bacillus anthracis." FEMS Microbiol Lett. 2017 Jun 12. doi: 10.1093/femsle/fnx127. 
• Fujioka K, et al. "The Powdering Process with a Set of Ceramic Mills for Green Tea Promoted Catechin Extraction and the ROS Inhibition Effect." Molecules. 2016 Apr 11;21(4):474. doi: 10.3390/molecules21040474.
• Heiss, Christian, et al. "Sustained increase in flow-mediated dilation after daily intake of high-flavanol cocoa drink over 1 week." Journal of cardiovascular pharmacology 49.2 (2007): 74-80.
• Kim, Tae-eun, et al. "effect of epigallocatechin-3-gallate, major ingredient of green tea, on the pharmacokinetics of rosuvastatin in healthy volunteers." Drug design, development and therapy 11 (2017): 1409.
• Lorenz, Mario, et al. "Tea-induced improvement of endothelial function in humans: No role for epigallocatechin gallate (EGCG)." Scientific Reports 7 (2017).
• Mancini, GB John, et al. "Diagnosis, prevention, and management of statin adverse effects and intolerance: proceedings of a Canadian Working Group Consensus Conference." Canadian Journal of Cardiology 27.5 (2011): 635-662.
• Papamichael, Chris M., et al. "Effect of coffee on endothelial function in healthy subjects: the role of caffeine." Clinical Science 109.1 (2005): 55-60.
• Randazzo, W. et al. "Effect of green tea extract on enteric viruses and its application as natural sanitizer." Food Microbiol. 2017 Sep;66:150-156. doi: 10.1016/j.fm.2017.04.018. Epub 2017 May 3.
• Raso, et al. "Effects of chronic consumption of green tea on weight and body fat distribution of Wistar rats evaluated by computed tomography." Acta Cir Bras. 2017 May;32(5):342-349. doi: 10.1590/s0102-865020170050000003.
• Serafini, Mauro et al. "Health Benefits of Tea" in Herbal Medicine: Biomolecular and Clinical Aspects. 2nd edition. Benzie IFF, Wachtel-Galor S, editors. Boca Raton (FL): CRC Press/Taylor & Francis; 2011.
• Shahid, Saleem Ullah, et al. "Effect of SORT1, APOB and APOE polymorphisms on LDL-C and coronary heart disease in Pakistani subjects and their comparison with Northwick Park Heart Study II." Lipids in health and disease 15.1 (2016): 83.
• Tehrani, H.G. et al.  "Effect of green tea on metabolic and hormonal aspect of polycystic ovarian syndrome in overweight and obese women suffering from polycystic ovarian syndrome: A clinical trial." J Educ Health Promot. 2017 May 5;6:36. doi: 10.4103/jehp.jehp_67_15. eCollection 2017.
• Tirosh, Oren, et al. "OP-17-Tea Extracts-induced Liver Injury: Lipotoxic Interaction Between Lipids and Polyphenols." Free Radical Biology and Medicine 108 (2017): S8.
• Tsai, et al. "Effect of green tea extract supplementation on glycogen replenishment in exercised human skeletal muscle." Br J Nutr. 2017 Jun 20:1-8. doi: 10.1017/S0007114517001374. [Epub ahead of print]
• Werba, Jose, P et al. "Overview of green tea interaction with cardiovascular drugs." Current pharmaceutical design 21.9 (2015): 1213-1219.

May I Salt & Roast My Nuts? Plus: If Catechins Boost One's Energy Expenditure by 400% Why Don't They Work for Me?

One article, two questions, two science-based answers.

If you're like me I bet that you've been asking yourself previously, whether the cheap roasted nuts at the supermarket have the same health benefits as the expensive "raw" nuts from the health-food store... guess what: a recent study by scientists from the Singapore Institute for Clinical Sciences and the University of Otago confirms: "Dry roasting and lightly salting nuts do[es] not appear to negate the cardioprotective effects observed with raw nut consumption, and both forms of nuts are resistant to [dietary] monotony" and thus similarly recommendable health-foods.

Along with the latest "green tea for thermogenesis"-study, which finally answers the important question "If Catechins Boost One's Energy Expenditure by 400% Why Don't They Work for Me?", the Chinese-New-Zealand co-production is one of the two studies in today's SuppVersity article.

Learn more about the effects of your diet on your health at the SuppVersity

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All About Cheese, Your Health, Per-formance & More

• You can roast and salt your nuts (all puns intended) and still see health benefits (Tey 2016): Unless you're like the average seventh-grader and misunderstand the previous statement, roasted and salted nuts display no health risk whatsoever.
  
  In fact, Siew Ling Tey and colleagues were recently able to show in a randomized crossover study with 72 perfectly healthy participants, who were asked to consume 30 g/day of either raw or dry roasted, lightly salted hazelnuts for 28 days, each that the CVD risk factors the scientists assessed still improved significantly (sign. changes in body composition were not recorded - just for the record: body fat declined by 100-200g, muscle mass increased by ca. 100g).
  

  

  Figure 1: Changes in biochemical parameters in the two groups; only the change in triglycerides (trigs) showed a probably random, yet statistically significant inter-group difference (in favor of the roasted nuts | Tey 2016)

  Furthermore, neither the "raw" nor the "roasted nut"-group saw a decline in their "desire to consume" and "overall liking" of the hazelnuts, which constitute, due to their relatively high omega-6 and extremely high PUFA content, an excellent study object for the potentially negative effects of roasting (one would expect a potential oxidation of PUFAs and downstream ill health effects). Moreover, studies "examining the health effects of consuming hazelnuts are", as the authors point out "relatively sparse despite the fact that hazelnuts are the second most common nut produced worldwide" (Tey 2016).
  
  One downside of roasted nuts I do not want to withhold, though, is the slight decrease in alpha-tocopherol during the roasting process, of which the results of the study do, however, indicate that it had no health-relevant consequences.
• Human study confirms: Green tea + caffeine set your brown fat on fire... assuming that you do have functional brown fat (Yoneshiro 2017) -- In rodents, it's not news that the combination of catechins and caffeine will promote brown adipose tissue thermogenesis. In humans, however, the effect has rarely been observed directly and is, as Yoneshiro et al. point out, "poorly understood".
  
  Reason enough for the Japanese scientists to recruit 15 healthy male volunteers, subject them to fluorodeoxyglucosepositron emission tomography and thus assess their BAT activity before and after a single oral ingestion of a beverage containing 615 mg catechin and 77 mg caffeine, as well as after the chronic ingestion of the same beverage 2 times/d for 5 wk in 10 of the subjects.
  

  

  Figure 2: (A) Study protocol of the acute trial. (B) Study protocol chronic trial. Both of the trials were single-blinded, randomized, placebo-controlled, season-matched crossover studies (Yoneshiro 2017).

  To complicate, ah... I mean to make the study more comprehensive the scientists also evaluated the cold-induced thermogenesis (CIT) after 2 h of "cold" exposure at cozy 19°C. Both the acute and chronic trials were single-blinded, randomized, placebo-controlled, season-matched crossover studies.
  

  

  Figure 3: Change in energy expenditure (adj. for FFM) after the ingestion of the test beverages (left). Thermogenic effects of the catechin or placebo beverage expressed as iAUC of EE (right | Yoneshiro 2017).

  What the authors found was in line with the observations in rodent studies - the effect size, however, was, as it was to be expected, magnitudes smaller; and, more importantly, occurred only in those subjects who were blessed with highly active brown fat depots:
  • A single ingestion of the catechin beverage increased EE in 9 subjects who had metabolically active BAT (mean ± SEM: +15.24 6 1.48 kcal, P < 0.01) but not in 6 subjects who had negligible activities (mean ± SEM: +3.42 6 2.68 kcal).
  • The ingestion of a placebo beverage containing 82 mg caffeine produced a smaller and comparative EE response in the 2 subject groups.
  The scientists multivariate regression analysis revealed a significant interaction between BAT and catechin on EE (b = 0.496, P = 0.003). In other words: The acute effects on your energy expenditure depend on the presence and activity of brown fat cells (see Figure 4).
  

  

  Figure 4: (A) Representative FDG-PET/CT images of the high- and low-BAT subjects. (B) Quantitative BAT activity as the SUV of the high- (n = 9) and low-BAT (n = 6) subjects (Yoneshiro 2017).

  Unfortunately, these fat cells which are already scarce in normal-weight human beings are quasi-non-existent (or dysfunctional, that's not 100% clear) in those people who'd need the fat-burning effects of green tea the most: the obese.
  
  Accordingly, it is important to point out that the beneficial effects of chronic GTE + caffeine intake on the thermogenic response to "cold" (19°C) exposure in the 10 normal-weight Japanese subjects may (and I would dare say that it "will") turn out poorly in the average obese individual.

This FDG-PET image shows where the average (lean) human has active BAT stores (van der Lans 2014).

So what's the verdict? While it is nice to know that roasting and (lightly) salting doesn't turn a health-food like nuts to poisonous trash, I guess that Yoneshiro's study sends the more important message to the fitness community. After all, they finally demonstrated that the answer to the question why green tea extracts don't work for you could be as simple as this: "That's because you don't have the brown fat that's responsive to the effects of the catechins."

That's huge because it shows that (a) the usefulness of green tea catechin supplements depends on the individuals and that (b) those who need "fat burners" the most, i.e. those who are still obese or struggling with their weight, are least likely to benefit from it.

After all, previous studies clearly indicate that the majority of morbidly obese (and older | Sacks 2013) subjects have virtually no brown fat/adipose tissue (Vijgen 2011 | or if they have it, it doesn't respond even to treatment w/ cold, insulin or ephedrine | Orava 2013; Carey 2013). In conjunction with the observation that there's a clear correlation between having active brown fat and having no weight problems (ibid.), as well as the realization that the activity of brown fat in the obese only increases after weight loss (Vijgen 2012), it is thus not surprising that many catechin users are disappointed | Comment on Facebook!

References:

• Carey, Andrew L., et al. "Ephedrine activates brown adipose tissue in lean but not obese humans." Diabetologia 56.1 (2013): 147-155.
• van der Lans, Anouk AJJ, et al. "Cold-activated brown adipose tissue in human adults: methodological issues." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 307.2 (2014): R103-R113.
• Orava, Janne, et al. "Blunted metabolic responses to cold and insulin stimulation in brown adipose tissue of obese humans." Obesity 21.11 (2013): 2279-2287.
• Sacks, Harold, and Michael E. Symonds. "Anatomical Locations of Human Brown Adipose Tissue." Diabetes 62.6 (2013): 1783-1790.
• Tey, Siew Ling, et al. "Do dry roasting, lightly salting nuts affect their cardioprotective properties and acceptability?." European journal of nutrition (2016): 1-12.
• Vijgen, Guy HEJ, et al. "Brown adipose tissue in morbidly obese subjects." PloS one 6.2 (2011): e17247.
• Vosselman, Maarten J., Wouter D. van Marken Lichtenbelt, and Patrick Schrauwen. "Energy dissipation in brown adipose tissue: from mice to men." Molecular and cellular endocrinology 379.1 (2013): 43-50.
• Yoneshiro, Takeshi, et al. "Tea catechin and caffeine activate brown adipose tissue and increase cold-induced thermogenic capacity in humans." The American Journal of Clinical Nutrition (2017): ajcn144972.

Green Tea Extract Reduces the Amount of Insulin You Need to Store Your PWO Carbs by ~20% + Discussed: What are the Potential Benefits During Bulking and Cutting?

The beneficial effects of green tea won't occur if you just put some GTE into your post-workout shake... well, at least they didn't occur in response to acute supplementation in the study at hand, where 3x350mg/d consumed for 7 days before a std. exercise + oral glucose tolerance test did the insulin lowering trick.

While green tea has a record of promoting the metabolic and overall health of the obese and sick, its benefits in healthy individuals are still an object of ongoing research. Research such as the latest study from the McMaster University, in which Brian J. Martin et al. (2016) evaluated the effect of supplementation with green tea extract (GTE) on the plasma glucose kinetics of eleven healthy, sedentary men (21±2 y; BMI=23±4 kg/m², VO2peak=38±7 ml/kg/min; mean±SD).

Now, this alone would probably not be SuppVersity newsworthy, but unlike other studies that assessed the effects of GTE on glucose management, Martin's study tested the effects specifically during the post-workout window - a fact that makes the study particularly interesting for SuppVersity readers.

Another important determinant of your 24h insulin levels is your meal frequency:

Grazin' Bad For the Obese!

Largest Meal For Lunch = Winner!?

Regularity is Key to Leanness

Optimal Meal Freq. 4 Kids?

8 Meals = Stable, But High Insulin

Are 6 Meals Better Than 2?

In contrast to what the study's title, "Green tea extract does not affect exogenous glucose appearance but reduces insulinemia with glucose ingestion in exercise recovery", suggests, we are not talking about an acute response study, here.

Simply adding some green tea extract to your PWO drink, alone, is thus unlikely to produce the same results. Rather than that you'd  better mirror the study protocol by consuming 350 mg of a standardized green tea extract thrice daily. After 7 days, which was the timespan after which Martin et al. conducted their oral glucose tolerance test, you should then be able to stash away a significantly larger amount of glucose with a given insulin load than before.

Figure 1: Post-workout glucose kinematics in response to a beverage containing 75g of glucose after 7 days of thrice daily green tea extract supplementation at a dosage of 3x350 mg (Martin. 2016).

As you can see in Figure 1 the chronic intake of GTE decreased the amount of insulin that was required to stash away the 75g of glucose the subjects consumed after participating in a graded exercise test (=cycling to exhaustion at ever-increasing intensities) was reduced by a statistically significant and practically relevant ~20%.

Why did GTE not improve the glucose AUC and the rates of glucose appearance and disappearance? Even though the experiment was not designed to elucidate this hypothesis, it is very likely that the lack of decreases of the amount of glucose in the blood, as well as its absorption kinetics, is probably the logical consequence of the fact that the uptake and storage already took place at the maximal physiological pace - though at sign. lower insulin levels w/ GTE.

Even though neither the glucose AUC, i.e. the amount of glucose that appeared in the blood, nor the glucose rate of appearance and disappearance decreased / increased significantly, said reduction in insulin is a clear indicator of a significantly improved insulin sensitivity - and that during a time-window where your cells' ability to take up and store glucose is already especially high, anyway.

Figure 2: Insulin is the most potent anabolic hormone known, and promotes the synthesis and storage of carbohydrates, lipids and proteins, while inhibiting their degradation and release into the circulation. Insulin stimulates the uptake of glucose, amino acids and fatty acids into cells, and increases the expression or activity of enzymes that catalyse glycogen, lipid and protein synthesis, while inhibiting the activity or expression of those that catalyse degradation (Saltiel. 2001).

In conjunction with the likewise improved oxidation of fatty acids during the workout, said reduction in insulin requirements may be an advantage during both cutting and bulking:

• cutting - during the former part of a "get jacked"-cycle, the reduced insulin excursions could shorten the time period during which elevated insulin levels suppress the release and oxidation of fatty acids from your fat stores while being in a caloric deficit
• bulking - during the latter part of the cycle, a reduced level of insulin could reduce the risk of fat storage while being in a caloric surplus

Eventually, it is important to note the italicization of "could" in the previously outlined hypotheses. Until their accuracy will have been proven in future studies, you better don't overestimate the results you may see from taking GTE supplements. Insulin is, after all, not half as obesogenic as Gary Taubes and co would have it... speaking of insulin: you probably don't have to be afraid to miss out on its beneficial effects on satiety and its ability to inhibit skeletal muscle protein breakdown - if the glucose AUC didn't change, it is after all very unlikely that the efficacy of insulin on other target organs wasn't increased to a similar degree so that you will experience the same satiety improving anti-catabolic effects with 20% less insulin; and yes, this means that, eventually, you could also experience the same degree of fat storage (luckily, though, PWO lipogenesis is → ZERO, anyway).

It may sound boring, but the classic combination of GTE and caffeine is probably the best fat burner left on the OTC supplement market | more

Bottom line: While future studies are, as so often, highly warranted, the study at hand provides initial evidence of the potential usefulness of green tea supplements in people who exercise regularly.

Whether the potential benefits, i.e. increased fat loss during cuts and decreased fat storage during bulks will actually occur in the everyday practice of athletic training and bodybuilding, however, is something that needs further research - research of which I'd hope that the guys at the McMaster University conduct it in the not all-too-distant future. After all, most of you will probably be more interested in the real world results than the mechanism of which Martin et al. write in the conclusion of the study at hand that it warrants further study | Comment on Facebook!

References:

• Martin, B.J. et al. "Green tea extract does not affect exogenous glucose appearance but reduces insulinemia with glucose ingestion in exercise recovery." Journal of Applied Physiology Published ahead of print on October 7, 2016 - DOI: 10.1152/japplphysiol.00657.2016
• Saltiel, Alan R., and C. Ronald Kahn. "Insulin signalling and the regulation of glucose and lipid metabolism." Nature 414.6865 (2001): 799-806.

Caffeine + Green Tea = Plus 10% Fat Oxidation & Energy Expenditure at Rest and During Sprint Interval Exercise

From a health perspective it may be good that green tea does not contain all-too much caffeine. From a fat loss perspective, it clearly lacks caffeine.

When it comes to dietary supplements, people like to pay tons of money for unproven ingredients with funky names and dubious or non-existent safety profiles; agents that have been scientifically proven to work, are safe and cheap, on the other hand, are non-sellers or at least considered to be non-effective.

Obviously, I cannot really explain why that is the case (I suspect it is because people effect drug-like effects without drug-like side-effects from supps and are thus always on the lookout for the "next big"... hoax), I can tell you, though, that a recent study that is going to be published in one of the upcoming issues of the Journal of Strength and Conditioning Research (Jo. 2015) shows that caffeine and green tea, two supplements that belong to the previously described category, are everything but useless.

You can learn more about coffee at the SuppVersity

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Caffeine Resis- tance - Does It Even Exist?

In said study, Edward Jo and colleagues investigated the effects of a caffeine + green tea polyphenol mix (250mg caffeine + 400mg of a green tea extract with 50% EGCG and 5mg of caffeine per serving) on (a) metabolic rate and fat oxidation at rest, as well as following a bout of sprint interval exercise (SIE) and (b) the performance during a standardized sprint-interval test.

The study was a double-blind, randomized, placebo-controlled, crossover study that involvd 12 subjects (male: n=11; female:1 n=1) whose antroprometric data, i.e "body mass=76.1±2.2 kg; height= 169.8±1.6 cm; BMI= 22.7±3.0 kg/m2; body fat %= 21.6±2.0% [DXA data]" (Jo. 2015), already tell you that they were healthy recreationally active, but not necessarily athletic (it may be worth mentioning that they were relatively stim-naive with an intake of < 201mg of caffeine per day).

Figure 1: Energy expenditure (kcal/h) and fat oxidation (g/day) measure before (at rest) and during (during SIE) the sprint interval exercise 10 and 55 minutes after the ingestion of caffeine + GTE or placebo (Jo. 2015).

During the two testing sessions at the Human Performance Research Laboratory of the California State Polytechnic University, the subjects' resting energy expenditure (REE) was measured for 45 minutes starting 10 minutes after the ingestion of the aforementioned caffeine + polyphenol mix - a mix that was consumed on an empty stomach after an 8-h overnight fast (don't be fooled by the way the scientists report their data in "g/day" and kcal/day - I changed the latter, already but the values for fat in g would have become to small - we are talking about 45 + 30 min and a 24h measurement here).

Don't confuse increases in fat oxidation w/ fat loss: I guess we have to credit the supplement industry for propagating the myth that the ratio of fat to glucose you were burning was in anyway directly related to losing body fat. I am not sure how often I've written this on this blog or told someone in the gym: that is not the case. You can burn 20% more fat and still store more body fat if you increase your energy intake from exactly enough to already too much. The connection between fatty acid oxidation which would actually be a better term for the phenomenon we are talking about is complicated and a decreasing respiratory exchange ratio, i.e. a reduction of the ratio of glucose to fat that's used to fuel your metabolism is not a reliable predictor of fat loss.

After the initial 45-minutes, during which the subjects' resting energy expenditure had been measured, the subjects were placed on a computer-integrated cycle ergometer on which they performed a standardized 30 minute sprint interval exercise (SIE) protocol., the scientists describe as follows:

"Sprint-Interval Exercise Protocol. The SIE protocol was performed on the Velotron DynaFit Pro cycle ergometer and comprised of four 30-second maximal effort intervals each separated by 5 minutes of low-intensity, constant workload cycling (Figure 2). First, the ergometer was properly adjusted for the subject. Adjustment specifications for each subject was recorded during their familiarization visit and repeated for all experimental trials. Subjects initiated the SIE protocol with a 5-minute interval of low-intensity cycling at a constant workload of 75W. Immediately after, subjects cycled with maximal effort for 30 seconds against an added resistance that is 7.5% of BW for males and 7.2% for females. These two intervals were repeated three additional times. After the last 30-second sprint interval, the subjects performed an additional low-intensity 75W interval plus an extra 3 minutes of cool-down at a constant workload of 30W. The total duration of the SIE protocol was 30 minutes" (Jo. 2015).

A workout that had little effect on the effect of the caffeine + green tea combo which did, as you can see, when you compare the "at rest" and "during SIE" values in Figure 1, increase the energy at rest and during sprint interval training to a similar extent. More specifically, the increase in energy expenditure and fat oxidation was - within the margin of inter-individual variability - in the range of +10% during both conditions.

Figure 2: Illustration of the sprint interval exercise test performed 55 min after ingesting the supplement (Jo. 2015).

In view of the fact that we may safely assume that this effect should last for at least 2-3h this can be a practically relevant effect if it is complemented by a reduced energy intake and a caloric deficit. If the latter is not present, even the extremest increases in fat oxidation and energy expenditure will fizzle out and be as irrelevant as the effect of the caffeine + green tea combination on exercise average and peak power (W) during the sprint training, Jo et al. observed in their study... and "Yes!", that is disappointing, but in view of the low dose of caffeine and the non-existent effects of green tea on performance during a test like this not really surprising.

Did you know this SuppVersity Calssic? "Post-Workout Coffee Boosts Glycogen Repletion by Up to 30% and May Even Have Sign. Glucose Partitioning Effects | learn more!

Bottom line: I admit, they certainly sound less exciting as the latest exotic herb from the rain-forest or a substance that is listed only under its funky chemical name on the label, but unlike your average "innovative breakthrough metabolic activator" caffeine and green tea will deliver. The 10% increase in metabolic rate and the accompanying increase in fat oxidation won't make you lose slabs of body fat, but the effects are pronounced enough to expect a measurable effect on the success of your next diet / cut. A cut, by the way, that will still require a significant reduction in energy intake, even if your energy expenditure and fat oxidation. So, don't be a fool and confuse a 10% increase in fat oxidation w/ a 10% increase in fat loss that occurs in the absence of dieting on an ad-libitum diet | Comment!

References:

• Jo et al. "Dietary Caffeine And Polyphenol Supplementation Enhances Overall Metabolic Rate And Lipid Oxidation At Rest And After A Bout Of Sprint Interval Exercise." Journal of Strength & Conditioning Research: Post Acceptance: November 23, 2015. doi: 10.1519/JSC.0000000000001277

Fat-Blocker Effect of Tea Catechins Confirmed (?) in Man - Sign. Abdominal Fat Loss (5-8%) in 12 Weeks W/Out Diet

Tea catechins (which can also be found in black and jasmin tea | see Figure 3) can help you keep particularly unhealthy abdominal fat (Després. 2012) at bay.

It is one thing to have in-vitro and rodent data that green tea can inhibit the digestion of dietary fat (reported previously in the SuppVersity Facebook News); it is another thing, however, to have a human study like the one Makoto Kobayashi and colleagues are about to publish in the peer-reviewed scientific journal Food & Function that shows that the "[i]ngestion of a green tea beverage enriched with catechins with a galloyl moiety (THEA-FLAN 90S) during a high-fat meal reduces body fat in moderately obese adults" (Kobayashi. 2015).

Ok, the abdominal fat loss does not, as the previous quote from the conclusion appears to suggest, occur instantly right after you've consumed your first tea w/ a single meal.

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Rather than that, 124 subjects (two of the initially 126 subjects 2 dropped out for personal reasons unrelated to the trial), 53 men, 71 women, who consumed similar, albeit non-standardized diets (see Figure 1 | note: physical activity was also identical) and began the study with body fat levels of ca. 31-35% had to consume the previously mentioned tea beverage that contained tea catechins (250 mL with 215.3 mg green tea catechins containing 211.0 mg green tea catechins with a galloyl moiety) twice or three times daily during mealtimes for 12 weeks, before the significant reduction in body fat became visible.

Figure 1: Macronutrient composition (in g an % of energy) of the non-energy reduced diets the subjects consumed; the values in the left pie chart represent a group average of all three intervention groups. Since the data is based on food records with photographs, it is probably more reliable than in your average diet study (Kobayashi. 2015).

Now, in view of the fact that this is not the first study to demonstrate weight loss effects in overweight subjects consuming green tea or, as in most other studies, green tea extracts, the word "during" and thus the fact that the green tea beverage was consumed with at least two of the three meals per day should be highlighted as a specific feature of the study at hand that is highly relevant to its interpretation.

Figure 2: Detailed analysis of the rel. change in fat area in the abdominal depot of the subjects (Kobayashi. 2015)

It is after all the requirement that the green tea beverage had to be consumed with a (preferable high fat) meal that allows the authors to conclude that the significant fat loss Kobayashi et al. measured by the means of computer tomography predominantly in the abdominal area are the result of an inhibition or slowing of the intestinal fat absorption and thus warrant the conclusion that "the ingestion of green tea beverages enriched with CGM together with high-fat meals may be an effective strategy for reducing body fat in moderately obese adults" (Kobayashi. 2015) - an observation of which I would like to add that the underlying mechanism is not 100% certain.

What about weight and, even more importantly, muscle loss? No, losing lean mass was not an issue in, because weight loss (-0.6 and -0.8% in the low and high dose group, respectively | measured by bio-electrical impedance vs. computer tomography as it was the case for the abdominal fat area) was actually not an issue, either. If you want to measure your success on the scale, green tea is thus not going to be the "diet tool of choice" (unless you use it alongside an energy-reduced diet)... however, if you take into account that the placebo group actually did what the average Westerner does, these days, i.e. gain weight and body fat over the 12-week study period, you may argue that you can still see the results on the scale which could finally stand still after years of displaying subtle, but eventually relevant increases in body weight.

The authors base their conclusion that it is "unlikely that absorbed green tea CGM leads to increased energy expenditure, followed by reduced abdominal body fat area" (Kobayashi. 2015) on two reasonable, but experimentally (in this study) not confirmed assumptions which are that little to no catechins actually made it into the bloodstream, because ...

1. the low caffeine content of the beverage limits the bioavailability of EGCG & co (caffeine enhances its bioavailability | Nakagawa. 2009) and
2. the ingestion of the beverage with a meal has been shown to significantly reduce the bioavailability of green tea catechins in comparison to the fasted state (Chow. 2005).

The assumption that its just a blockade of the digestion of fat becomes even more questionable, if you (re-)read my 2014 article on the carb blocking effects of tea... Well, eventually, though, you may argue that it does not matter if the reduction in abdominal fat was due to thermogenic effects, thermogenic and fat-blocking effects or, as the scientists believe, mediated exclusively an "inhibit[ion] or slowing [of the subjects'] intestinal fat absorption" (Kobayashi. 2015). And let's be honest, I guess you're right. What matters is that there were significant reduction ins abdominal fat (visceral, subcutaneous and total abdominal fat area). Reduction of which the data in Figure 2 tells you that ...

1. 

   Table 1: Catechin composition of the test beverages.

   the fat loss in the abdominal area was dose dependent - even if the differences between the low and high dose group did not reach statistical significance (for the exact catechin composition see Table 1 on the right) - and that 
2. roughly 50% of the benefits were lost within only 5 weeks when the subjects stopped consuming the green tea beverage, even though their diet didn't change at all (in fact, they consumed minimally less energy in the withdrawal phase from week 12-17).

Now, (b) is obviously good news for green tea lovers, but bad news for those who cannot imagine consuming green tea containing beverages "for the rest of their lives".

Green tea forever, it is then!? Well, as usual we have to consider what limits the generalizability of the results. Firstly, we are dealing with a group of people who have more than a few pounds of extra-weight on their hips. An abdominal fat loss of 8% in 12 weeks is thus not impossible, but not exactly likely to be seen in someone who starts at a body fat percentage of 15% or less (which is half what the subjects in the study at hand began with).

Figure 3: Catechin content (mg/10ml) of black, green and jasmine tea prepared from commercial tea w/ different infusion times (Bronner. 1998).

The second thing we have to keep in mind is the beverage itself. As you've previously read, it has been enhanced with catechins with a galloyl moiety (CGMs | EGCG, ECG, GCG, CG). Does this mean that you cannot achieve similar results if you simply drink green tea? Luckily, data from Bronner, et al. (1998) suggests otherwise. As you can see in Figure 3, it would take only 100 ml of commercially available freshly brewed (infusion time 3 min) green tea and even less black tea to achieve similar concentrations of EGCG and the other catechins with a galloyl moiety in your tea. Accordingly, the second obstacle to the gene- relizability of the study is actually irrelevant.

Third- and lastly, there's yet still the fast reversal of the effects which suggests that it is necessary to become a habitual tea drinker to see long-term / lasting benefits of green tea (or as the data in Figure 3 suggests even catechin containing tea in general) on your body weight and, more importantly, body fat you're carrying around | Comment on Facebook!

References:

• Bronner, W. E., and G. R. Beecher. "Method for determining the content of catechins in tea infusions by high-performance liquid chromatography." Journal of Chromatography A 805.1 (1998): 137-142.
• Chow, HH Sherry, et al. "Effects of dosing condition on the oral bioavailability of green tea catechins after single-dose administration of Polyphenon E in healthy individuals." Clinical Cancer Research 11.12 (2005): 4627-4633.
• Després, Jean-Pierre. "Body fat distribution and risk of cardiovascular disease an update." Circulation 126.10 (2012): 1301-1313.
• Kobayashi, Makoto, et al. "Green tea beverages enriched with catechins with a galloyl moiety reduce body fat in moderately obese adults: a randomized double-blind placebo-controlled trial." Food & Function (2016).
• Nakagawa, Kiyotaka, et al. "Effects of co-administration of tea epigallocatechin-3-gallate (EGCG) and caffeine on absorption and metabolism of EGCG in humans." Bioscience, biotechnology, and biochemistry 73.9 (2009): 2014-2017.