title: Epigallocatechin-3-gallate and postprandial fat oxidation in overweight/obese male volunteers: a pilot study Effects of encapsulated green tea and Guarana extracts containing a mixture of epigallocatechin-3-gallate and caffeine on 24 h energy expenditure and fat oxidation in men. Green tea extract reduces blood pressure, inflammatory biomarkers, and oxidative stress and improves parameters associated with insulin resistance in obese, hypertensive patients. The Effects of Epigallocatechin-3-Gallate on Thermogenesis and Fat Oxidation in Obese Men: A Pilot Study Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidation in humans. Green tea catechin consumption enhances exercise-induced abdominal fat loss in overweight and obese adults. The Cochrane Collaboration’s tool for assessing risk of bias in randomised trials Effects of Chinese Green Tea on Weight, and Hormonal and Biochemical Profiles in Obese Patients With Polycystic Ovary Syndrome—A Randomized Placebo-Controlled Trial Supplementation of green tea catechins in dentifrices suppresses gingival oxidative stress and periodontal inflammation. Health effects of green tea catechins in overweight and obese men: a randomised controlled cross-over trial. Effect of green tea extract on obese women: a randomized, double-blind, placebo-controlled clinical trial. Epigallocatechin-3-gallate increases maximal oxygen uptake in adult humans. Cholesterol-lowering effect of a theaflavin-enriched green tea extract: a randomized controlled trial. The effects of EGCG on fat oxidation and endurance performance in male cyclists.
abstract: Objectives : Drinking green tea is associated with many health benefits , including increased fat oxidation . We tested the hypothesis that epigallocatechin-3-gallate ( EGCG ) , the main green tea catechin , increases  fat oxidation in obese men . Methods : Ten healthy overweight/obese males ( body mass index 31.3±0.8 kg/m2 ) were studied in a r and omized , placebo-controlled , double-blind crossover trial . Study supplements were low EGCG ( 300 mg ) , high EGCG ( 600 mg ) , caffeine ( 200 mg ) , EGCG/caffeine ( 300 mg/200 mg ) or placebo and were taken orally for 3 days . At the third day of supplementation , O2 consumption and CO2 production was measured by indirect calorimetry to assess energy expenditure and fat oxidation over 4 h each after overnight fasting and after a st and ardized test meal . Results : Energy expenditure was not affected by any supplementation , neither after overnight fasting nor after the test meal . During the first 2 h after overnight fasting , fat oxidation increased by 7.7 ( not significant , NS ) , 15.2 ( NS ) , 26.3 ( P<0.05 vs placebo ) and 35.4 % ( P<0.01 vs placebo and low EGCG ) , for low EGCG , high EGCG , caffeine and EGCG/caffeine , respectively . During the first 2 h after the meal , the mean increase in fat oxidation was 33.3 ( P<0.05 vs placebo ) , 20.2 ( NS ) , 34.5 ( P<0.05 vs placebo ) and 49.4 % ( P<0.05 vs placebo ) for low EGCG , high EGCG , caffeine and EGCG/caffeine , respectively . Conclusions : Low EGCG increases postpr and ial fat oxidation  in obese men and this to the same extent as 200 mg caffeine , whereas high EGCG does not exert this effect . Fasting fat oxidation is increased only by caffeine ( with or without EGCG ) . There is no synergism of low EGCG and 200 mg caffeine . Energy expenditure is not affected by EGCG It has been reported that green tea has a thermogenic effect , due to its caffeine content and probably also to the catechin , epigallocatechin-3-gallate ( EGCG ) . The main aim of the present study was to compare the effect of a mixture of green tea and Guarana extracts containing a fixed dose of caffeine and variable doses of EGCG on 24 h energy expenditure and fat oxidation .  Fourteen subjects took part to this r and omized , placebo-controlled , double-blind , cross-over study . Each subject was tested five times in a metabolic chamber to measure 24 h energy expenditure , substrate oxidation and blood pressure . During each stay , the subjects ingested a capsule of placebo or capsules containing 200 mg caffeine and a variable dose of EGCG ( 90 , 200 , 300 or 400 mg ) three times daily , 30 min before st and ardized meals . Twenty-four hour energy expenditure increased significantly by about 750 kJ with all EGCG-caffeine mixtures compared with placebo . No effect of the EGCG-caffeine mixture was observed for lipid oxidation . Systolic and diastolic blood pressure increased by about 7 and 5 mmHg , respectively , with the EGCG-caffeine mixtures compared with placebo . This increase was significant only for 24 h diastolic blood pressure . The main finding of the study was the increase in 24 h energy expenditure with the EGCG-caffeine mixtures . However , this increase was similar with all doses of EGCG in the mixtures Green tea ( GT ) consumption is known to be associated with enhanced cardiovascular and metabolic health . The purpose of this study is to examine the hypothesis that supplementation with GT alters insulin resistance and associated cardiovascular risk factors in obese , hypertensive patients . In a double-blind , placebo-controlled trial , 56 obese , hypertensive subjects were r and omized to receive a daily supplement of 1 capsule that contained either 379 mg of GT extract ( GTE ) or a matching placebo , for 3 months . At baseline and after 3 months of treatment , the anthropometric parameters , blood pressure , plasma lipid levels , glucose levels , creatinine levels , tumor necrosis factor α levels , C-reactive protein levels , total antioxidant status , and insulin levels were assessed . Insulin resistance was evaluated according to the homeostasis model assessment -insulin resistance protocol . After 3 months of supplementation , both systolic and diastolic blood pressures had significantly decreased in the GTE group as compared with the placebo group ( P < .01 ) . Considerable ( P < .01 ) reductions in fasting serum glucose and insulin levels and insulin resistance were observed in the GTE group when compared with the placebo group . Serum tumor necrosis factor α and C-reactive protein were significantly lower , whereas total antioxidant status increased in the GTE group compared with the placebo ( P < .05 ) . Supplementation also contributed to significant ( P < .05 ) decreases in the total and low-density lipoprotein cholesterol and triglycerides , but an increase in high-density lipoprotein cholesterol . In conclusion , daily supplementation with 379 mg of GTE favorably influences blood pressure , insulin resistance , inflammation and oxidative stress , and lipid profile in patients with obesity-related hypertension Objectives : The development of obesity is characterized by an increase in adipose tissue mass and by concomitant and profound changes in almost all organ functions leading to diseases such as hypertension , diabetes mellitus and coronary heart disease . Recent data from human studies indicate that the consumption of green tea and green tea extracts may help reduce body weight , mainly body fat , by increasing postpr and ial thermogenesis and fat oxidation . However , human studies investigating the metabolic effects of the most predominant tea catechin , EGCG , alone are absent . Methods : In a r and omized double blind , placebo-controlled , cross-over pilot study , six overweight men were given 300 mg EGCG/d for 2d . Fasting and postpr and ial changes in energy expenditure ( EE ) and substrate oxidation were assessed . Results : Resting EE did not differ significantly between EGCG and placebo treatments , although during the first postpr and ial monitoring phase , respiratory quotient ( RQ ) values were significantly lower with EGCG compared to the placebo . Conclusions : These findings suggest that EGCG alone has the potential to increase fat oxidation in men and may thereby contribute to the anti-obesity effects of green tea . However , more studies with a greater sample size and a broader range of age and BMI are needed to define the optimum dose BACKGROUND Current interest in the role of functional foods in weight control has focused on plant ingredients capable of interfering with the sympathoadrenal system . OBJECTIVE We investigated whether a green tea extract , by virtue of its high content of caffeine and catechin polyphenols , could increase 24-h energy expenditure ( EE ) and fat oxidation in humans . DESIGN Twenty-four-hour EE , the respiratory quotient ( RQ ) , and the urinary excretion of nitrogen and catecholamines were measured in a respiratory chamber in 10 healthy men . On 3 separate occasions , subjects were r and omly assigned among 3 treatments : green tea extract ( 50 mg caffeine and 90 mg epigallocatechin gallate ) , caffeine ( 50 mg ) , and placebo , which they ingested at breakfast , lunch , and dinner . RESULTS Relative to placebo , treatment with the green tea extract result ed in a significant increase in 24-h EE ( 4 % ; P < 0.01 ) and a significant decrease in 24-h RQ ( from 0.88 to 0.85 ; P < 0.001 ) without any change in urinary nitrogen . Twenty-four-hour urinary norepinephrine excretion was higher during treatment with the green tea extract than with the placebo ( 40 % , P < 0.05 ) . Treatment with caffeine in amounts equivalent to those found in the green tea extract had no effect on EE and RQ nor on urinary nitrogen or catecholamines . CONCLUSIONS Green tea has thermogenic properties and promotes fat oxidation beyond that explained by its caffeine content per se . The green tea extract may play a role in the control of body composition via sympathetic activation of thermogenesis , fat oxidation , or both This study evaluated the influence of a green tea catechin beverage on body composition and fat distribution in overweight and obese adults  during exercise-induced weight loss . Participants ( n = 132 with 107 completers ) were r and omly assigned to receive a beverage containing approximately 625 mg of catechins with 39 mg caffeine or a control beverage ( 39 mg caffeine , no catechins ) for 12 wk . Participants were asked to maintain constant energy intake and engage in > or=180 min/wk moderate intensity exercise , including > or=3 supervised sessions per week . Body composition ( dual X-ray absorptiometry ) , abdominal fat areas ( computed tomography ) , and clinical laboratory tests were measured at baseline and wk 12 . There was a trend ( P = 0.079 ) toward greater loss of body weight in the catechin group compared with the control group ; least squares mean ( 95 % CI ) changes , adjusted for baseline value , age , and sex , were -2.2 ( -3.1 , -1.3 ) and -1.0 ( -1.9 , -0.1 ) kg , respectively . Percentage changes in fat mass did not differ between the catechin [ 5.2 ( -7.0 , -3.4 ) ] and control groups [ -3.5 ( -5.4 , 1.6 ) ] ( P = 0.208 ) . However , percentage changes in total abdominal fat area [ -7.7 ( -11.7 , -3.8 ) vs. -0.3 ( -4.4 , 3.9 ) ; P = 0.013 ] , subcutaneous abdominal fat area [ -6.2 ( -10.2 , -2.2 ) vs. 0.8 ( -3.3 , 4.9 ) ; P = 0.019 ] , and fasting serum triglycerides ( TG ) [ -11.2 ( -18.8 , -3.6 ) vs. 1.9 ( -5.9 , 9.7 ) ; P = 0.023 ] were greater in the catechin group . These findings suggest that green tea catechin consumption enhances exercise-induced changes in abdominal fat and serum TG Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more Objectives : To study the effects of green tea on body weight , and biochemical and hormonal profiles in obese Chinese women with polycystic ovary syndrome ( PCOS ) . Methods : Thirty-four obese Chinese women with PCOS were r and omized into either treatment with green tea capsules or placebo for 3 months . The anthropomentric measurements , and biochemical and hormonal profiles before and after treatment in each group were compared . Results : The body weight of the green tea group decreased by a nonsignificant 2.4 % after treatment ; whereas the body weight , body mass index ( BMI ) , and body fat content of the control group were significantly higher after 3 months . There were no differences in any of the hormone levels measured in either group . The biochemical profiles of the two groups were also similar except that there was a small but significant rise in the triglyceride level in the green tea group . Fewer patients in the green tea group remained amenorrhoeic , but this was not significantly different from the control group . Conclusions : Green tea supplementation did not significantly reduce body weight in obese women with PCOS , nor did it alter the glucose or lipid metabolism OBJECTIVE this study examined the effects of a dentifrice containing green tea catechins on  gingival oxidative stress and periodontal inflammation using a rat model . DESIGN twenty-four male Wister rats were r and omly divided into four groups . The first group ( Control group ) received no treatment for 8 weeks . Periodontal inflammation was induced in the second group for 8 weeks . Periodontal inflammation was induced in the last two groups for 8 weeks and dentifrices with or without green tea catechins were topically applied to the gingival sulcus daily for 4 weeks prior to the end of the experimental period . RESULTS rats that had experimental periodontal inflammation showed apical migration of the junctional epithelium , alveolar bone loss and inflammatory cell infiltration in the connective tissue subjacent to the junctional epithelium at 8 weeks , whilst the control group showed no pathologic changes . Topical application of a green tea catechin-containing dentifrice reduced inflammatory cell infiltration in the periodontal lesions to a greater degree than the control dentifrice at 8 weeks . The gingiva in which green tea catechin-containing dentifrice was applied also showed a lower level of expression of hexanoyl-lysine ( a marker of lipid peroxidation ) , nitrotyrosine ( a marker of oxidative protein damage ) , and tumour necrosis factor-α ( an indicator of pro-inflammatory cytokines ) at 8 weeks compared to gingiva in which the control dentifrice was applied . CONCLUSIONS adding green tea catechins to a dentifrice may contribute to prevention of periodontal inflammation by decreasing gingival oxidative stress and expression of pro-inflammatory cytokines Regular consumption of green tea may be cardioprotective . In the present study we investigated the health effects of dietary supplementation with green tea catechins and the potential modifying effect of the catechol-O-methyltransferase ( COMT ) Val/Met genotype . Subjects ( sedentary males , aged 40 - 69 years , with BMI ≥ 28 and ≤ 38 kg/m(2 ) ) were r and omly assigned to consume decaffeinated green tea extract ( DGT ; 530 mg containing about 400 mg total catechins/capsule , twice daily ) and placebo in a complete cross-over design . Ambulatory blood pressure and biomarkers of metabolic function ( cholesterol , TAG , glucose and insulin ) were measured at weeks 0 and 6 . Although a marked increase in the concentration of plasma epigallocatechin gallate ( EGCG ) , urinary epigallocatechin ( EGC ) and urinary 4'-O-methyl EGC was found after DGT treatment , no effect on blood pressure or biomarkers of metabolic function was observed . However , a period × treatment interaction ( P < 0·05 ) was detected for body-weight change . 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 . Additionally , the COMT Val/Met genotype influenced urinary accumulation of EGC and 4'-O-methyl EGC ( P < 0·01 ) . Mean concentrations were lower in individuals homozygous for the high-activity G-allele , possibly reflecting increased metabolic flux and a more rapid conversion to downstream metabolic species , compared with individuals carrying at least one copy of the low-activity A-allele . Additional studies are needed to confirm these findings and further explore the modifying effect of genotype AIMS To examine the effect of green tea extract ( GTE ) on obese women and to explore the relationship between GTE and obesity-related hormone peptides . METHODS A r and omized , double-blind , placebo-controlled clinical trial was conducted from July 2006 to June 2007 in Taipei Hospital , Taiwan . Seventy-eight of 100 obese women aged between 16 and 60 years with BMI > 27 kg/m(2 ) and who had not received any other weight control maneuvers within the last 3 months completed this study . The subjects were r and omly divided into Groups A and B. Group A ( n=41 ) received GTE while Group B ( n=37 ) took cellulose as a placebo , one capsule ( 400 mg ) three times each day for 12 weeks . The body weight ( BW ) , body mass index ( BMI ) and waist circumflex ( WC ) were measured at the beginning of the study and after 12 weeks of treatment with GTE . The data were compared and expressed as % reduction . RESULTS There was only a 0.3 % reduction in BW ( 0.15 kg ) after 12 weeks of treatment with GTE . There was no statistical difference in % reduction in BW , BMI and WC between the GTE and placebo groups . Within group comparison revealed that the GTE group had significant reduction in LDL-cholesterol and triglyceride , and marked increase in the level of HDL-cholesterol , adiponectin and ghrelin . On the other h and , the placebo group showed significant reduction in triglyceride only , and a marked increase in the level of ghrelin alone . CONCLUSIONS This study showed no statistical difference in % reduction in BW , BMI and WC between the GTE and placebo groups after 12 weeks of treatment . The intake of GTE ( 491 mg catechins containing 302 mg EGCG ) for 12 weeks is considered safe as shown by the results UNLABELLED Epigallocatechin-3-gallate ( EGCG ) , a component of green tea , increases endurance performance in animals and promotes fat oxidation during cycle ergometer exercise in adult humans . PURPOSE We have investigated the hypothesis that short-term consumption of EGCG delays the onset of the ventilatory threshold ( VT ) and increases maximal oxygen uptake ( VO2max ) . METHODS In this r and omized , repeated- measures , double-blind study , 19 healthy adults ( 11 males and 8 females , age = 26 ± 2 yr ( mean ± SE ) ) received seven placebo  or seven EGCG ( 135-mg ) pills . Forty-eight hours before data collection , participants began consuming three pills per day ; the last pill was taken 2 h before exercise testing . VT and VO2max were determined from breath-by-breath indirect calorimetry data collected during continuous incremental stationary cycle ergometer exercise ( 20 - 35 W·min(-1 ) ) , from rest until volitional fatigue . Each condition/exercise test was separated by a minimum of 14 d. RESULTS Compared with placebo , short-term EGCG consumption increased VO2max ( 3.123 ± 0.187 vs 3.259 ± 0.196 L·min(-1 ) , P = 0.04 ) . Maximal work rate ( 301 ± 15 vs 301 ± 16 W , P = 0.98 ) , maximal RER ( 1.21 ± 0.01 vs 1.22 ± 0.02 , P = 0.27 ) , and maximal HR were unaffected ( 180 ± 3 vs 180 ± 3 beats·min(-1 ) , P = 0.87 ) . In a subset of subjects ( n = 11 ) , maximal cardiac output ( determined via open-circuit acetylene breathing ) was also unaffected by EGCG ( 29.6 ± 2.2 vs 30.2 ± 1.4 L·min(-1 ) , P = 0.70 ) . Contrary to our hypothesis , EGCG  decreased VO2 at VT ( 1.57 ± 0.11 vs 1.48 ± 0.10 L·min(-1 ) ) , but this change was not significant ( P = 0.06 ) . CONCLUSIONS Short-term consumption of EGCG  increased VO2max without affecting maximal cardiac output , suggesting that EGCG may increase arterial-venous oxygen difference BACKGROUND Tea consumption has been associated with decreased cardiovascular risk , but potential mechanisms of benefit are ill-defined . While epidemiologic studies suggest that drinking multiple cups of tea per day lowers low-density lipoprotein cholesterol ( LDL-C ) , previous trials of tea drinking and administration of green tea extract have failed to show any impact on lipids and lipoproteins in humans . Our objective was to study the impact of a theaflavin-enriched green tea extract on the lipids and lipoproteins of subjects with mild to moderate hypercholesterolemia . METHODS Double-blind , r and omized , placebo-controlled , parallel-group trial set in outpatient clinics in 6 urban hospitals in China . A total of 240 men and women 18 years or older on a low-fat diet with mild to moderate hypercholesterolemia were r and omly assigned to receive a daily capsule containing theaflavin-enriched green tea extract ( 375 mg ) or placebo for 12 weeks . Main outcome measures were mean percentage changes in total cholesterol , LDL-C , high-density lipoprotein cholesterol ( HDL-C ) , and triglyceride levels compared with baseline . RESULTS After 12 weeks , the mean + /- SEM changes from baseline in total cholesterol , LDL-C , HDL-C , and triglyceride levels were -11.3 % + /- 0.9 % ( P = .01 ) , -16.4 % + /- 1.1 % ( P = .01 ) , 2.3 % + /- 2.1 % ( P = .27 ) , and 2.6 % + /- 3.5 % ( P = .47 ) , respectively , in the tea extract group . The mean levels of total cholesterol , LDL-C , HDL-C , and triglycerides did not change significantly in the placebo group . No significant adverse events were observed . CONCLUSION The theaflavin-enriched green tea extract we studied is an effective adjunct to a low-saturated-fat diet to reduce LDL-C in hypercholesterolemic adults and is well tolerated Research ers have long been investigating strategies that can increase athletes ' ability to oxidize fatty acids and spare carbohydrate , thus potentially improving endurance capacity .  Green-tea extract ( epigallocatechin-3-gallate ; EGCG ) has been shown to improve endurance capacity in mice . If a green-tea extract can stimulate fat oxidation and as a result spare glycogen stores , then athletes may benefit through improved endurance performance . Eight male cyclists completed a study incorporating a 3-way crossover , r and omized , placebo-controlled , double-blinded , diet-controlled research design . All participants received 3 different treatments ( placebo 270 mg , EGCG 270 mg , and placebo 270 mg + caffeine 3 mg/kg ) over a 6-day period and 1 hr before exercise testing . Each participant completed 3 exercise trials consisting of 60 min of cycling at 60 % maximum oxygen uptake ( VO2(max ) ) immediately followed by a self-paced 40-km cycling time trial . The study found little benefit in consuming green-tea extract on fat oxidation or cycling performance , unlike caffeine , which did benefit cycling performance . The physiological responses observed during submaximal cycling after caffeine ingestion were similar to those reported previously , including an increase in heart rate  ( EGCG 147 + /- 17 , caffeine 146 + /- 19 , and placebo 144 + /- 15 beats/min ) , glucose at the 40-min exercise time point ( placebo 5.0 + /- 0.8 , EGCG 5.4 + /- 1.0 , and caffeine 5.8 + /- 1.0 mmol/L ) , and resting plasma free fatty acids and no change in the amount of carbohydrate and fat being oxidized . Therefore , it was concluded that green-tea extract offers no additional benefit to cyclists over and above those achieved by using caffeine
target: Changes in FOX did not reach the level of statistical significance .
  Finding showed that EGCG intake moderately accelerates EE and reduces RQ .
  The analyses revealed that the EGCG result ed in difference in RQ and EE but the effect on the other measures of energy metabolism was relatively mild .
  Possibly , EGCG alone has the potential to increase metabolic rate at 300 mg dose .
  Collectively , the outcome supports the findings that EGCG has an effect on metabolic parameters .
background: Green tea catechins ( GTCs ) are known to improve fat oxidation ( FOX ) during fasted , rested and exercise conditions wherein epigallocatechin-3-gallate ( EGCG ) is thought to be the most pharmacologically active and has been studied extensively .
  From the available data of r and omized controlled trials ( RCTs ) on EGCG , we carried out a systematic review and meta- analysis to eluci date whether EGCG consumption indeed increase energy expenditure ( EE ) and promote FOX .