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Oolong Tea Increases Metabolic Rate and Fat Oxidation in Men
Abstract
According to traditional Chinese belief, oolong tea is effective in the control of body weight. Few controlled studies, however, have been conducted to measure the impact of tea on energy expenditure (EE) of humans. A randomized cross-over design was used to compare 24-h EE of 12 men consuming each of four treatments: 1) water, 2) full-strength tea (daily allotment brewed from 15 g of tea), 3) half-strength tea (brewed from 7.5 g tea) and 4) water containing 270 mg caffeine, equivalent to the concentration in the full-strength tea treatment. Subjects refrained from consuming caffeine or flavonoids for 4 d prior to the study. Tea was brewed each morning; beverages were consumed at room temperature as five 300 mL servings. Subjects received each treatment for 3 d; on the third day, EE was measured by indirect calorimetry in a room calorimeter. For the 3 d, subjects consumed a typical American diet. Energy content of the diet was tailored to each subject's needs as determined from a preliminary measure of 24-h EE by calorimetry. Relative to the water treatment, EE was significantly increased 2.9 and 3.4% for the full-strength tea and caffeinated water treatments, respectively. This increase over water alone represented an additional expenditure of 281 and 331 kJ/d for subjects treated with full-strength tea and caffeinated water, respectively. In addition, fat oxidation was significantly higher (12%) when subjects consumed the full-strength tea rather than water.
... Green tea or its individual constituents have been shown to alter resting energy metabolism. Several short-term (< 3 days) supplementation studies have found an increase in resting energy expenditure [3][4][5][6]; however, this has not always been the case [7][8][9]. In studies that have found increased energy expenditure, this was related to an increase in lipid metabolism [4,6]. ...
... Several short-term (< 3 days) supplementation studies have found an increase in resting energy expenditure [3][4][5][6]; however, this has not always been the case [7][8][9]. In studies that have found increased energy expenditure, this was related to an increase in lipid metabolism [4,6]. For example, green tea ingestion (EGCG 245 mg.d −1 , caffeine 270 mg.d −1 ) increased resting energy expenditure by 2.9% and lipid oxidation rates by 12% higher over the 24-h period compared with water [6]. ...
... In studies that have found increased energy expenditure, this was related to an increase in lipid metabolism [4,6]. For example, green tea ingestion (EGCG 245 mg.d −1 , caffeine 270 mg.d −1 ) increased resting energy expenditure by 2.9% and lipid oxidation rates by 12% higher over the 24-h period compared with water [6]. Some studies have demonstrated no change in resting energy expenditure but found an increased lipid oxidation rate [7,9]. ...
Purpose
Physical exercise is shown to mitigate catecholamine metabolites; however, it is unknown if exercise-induced increases in sympatho-adrenal activity or catecholamine metabolites are influenced by ingestion of specific catechins found within green tea. This study explored the impact of epigallocatechin gallate (EGCG) ingestion on catecholamine metabolism during graded cycle exercise in humans.
Methods
Eight males (22.4 ± 3.3 years, BMI:25.7 ± 2.4 kg.m ² ) performed a randomised, placebo-controlled, single-blind, cross-over trial after consumption (1450 mg) of either EGCG or placebo (PLAC) and performed graded cycling to volitional exhaustion. Venous bloods were taken at rest, 2 h post-ingestion and after every 3-min stage. Blood variables were analysed for catecholamines, catecholamine metanephrines and metabolic variables at rest, 2 h post-ingestion (POST-ING), peak rate of lipid oxidation (FATpeak), lactate threshold (LT) and peak rate of oxygen consumption ( V O 2 peak). Data were analysed using SPSS (Version 26).
Results
Resting catecholamine and metanephrines were similar between trials. Plasma adrenaline (AD) was lower in ECGC treatment group between trials at FATpeak ( P < 0.05), LT ( P < 0.001) and V O 2 peak ( P < 0.01). Noradrenaline (NA) was lower under EGCG at POST ( P < 0.05), FATpeak ( P < 0.05), LT ( P < 0.01) and V O 2 peak ( P < 0.05) compared to PLAC. Metanephrines, glucose and lactate increased similarly with exercise intensity in both trials. Lipid oxidation rate was 32% lower in EGCG at FATpeak (EGCG 0.33 ± 0.14 vs. PLAC 0.49 ± 0.11 g.min ⁻¹ , P < 0.05). Cycle time to exhaustion was similar (NS).
Conclusion
Acute EGCG supplementation reduced circulating catecholamines but not; metanephrine, glucose or lactates, response to graded exercise. Lower circulating catecholamines may explain a lower lipid oxidation rate.
... The effects of tea on energy metabolism have been assessed in parallel with the effects of caffeine. Many studies report that accumulated energy expenditure over 24 h is increased by caffeine ingestion [2][3][4], although one study found no effect [5]. The effect of caffeine ingestion on accumulated fat oxidation over 24 h, however, was not examined in any of these four studies [2][3][4][5]. ...
... Many studies report that accumulated energy expenditure over 24 h is increased by caffeine ingestion [2][3][4], although one study found no effect [5]. The effect of caffeine ingestion on accumulated fat oxidation over 24 h, however, was not examined in any of these four studies [2][3][4][5]. Ingestion of green tea extract increases 24-h energy expenditure and decreases the 24-h respiratory quotient (RQ) [5]. Another study found that 3 days of oolong tea ingestion increased the accumulated energy expenditure and fat oxidation over 24 h, whereas caffeine alone did not significantly increase 24-h fat oxidation [4]. ...
... Ingestion of green tea extract increases 24-h energy expenditure and decreases the 24-h respiratory quotient (RQ) [5]. Another study found that 3 days of oolong tea ingestion increased the accumulated energy expenditure and fat oxidation over 24 h, whereas caffeine alone did not significantly increase 24-h fat oxidation [4]. Thus, unidentified ingredient(s) of tea other than caffeine affects energy metabolism, particularly fat oxidation. ...
Ingesting oolong tea or caffeine acutely increases energy expenditure, and oolong tea, but not caffeine, stimulates fat oxidation. The acute effects of caffeine, such as increased heart rate and interference with sleep, diminish over 1-4 days, known as caffeine tolerance. During each 14-day session of the present study, 12 non-obese males consumed oolong tea (100 mg caffeine, 21.4 mg gallic acid, 97 mg catechins and 125 mg polymerized polyphenol), caffeine (100 mg), or placebo at breakfast and lunch. On day 14 of each session, 24-h indirect calorimetry and polysomnographic sleep recording were performed. Caffeine and oolong tea increased fat oxidation by~20% without affecting energy expenditure over 24-h. The decrease in the respiratory quotient by oolong tea was greater than that by caffeine during sleep. The effect of oolong tea on fat oxidation was salient in the post-absorptive state. These findings suggest a role of unidentified ingredients in oolong tea to stimulate fat oxidation, and this effect is partially suppressed in a postprandial state. Two weeks of caffeine or oolong tea ingestion increased fat oxidation without interfering with sleep. The effects of subacute ingestion of caffeine and oolong tea differed from the acute effects, which is a particularly important consideration regarding habitual tea consumption.
... Five human studies (n = 66 males, n = 16 females) conducted in metabolic chambers used caffeine doses of 150 to 600 mg with varying amounts of green tea catechins and epigallocatechin-3-gallate (EGCG) (240 to 1200 mg) [7][8][9][10][11]. Increases in 24 h energy expenditure (24 h EE) with catechin-caffeine mixtures varied from 2% to 8% and were related more or entirely to the caffeine portion of the supplement. ...
... Ingestion of catechin-caffeine mixtures may increase fat oxidation better than caffeine alone, but this finding has not been consistently supported in the few studies available. Two of the five studies showed that relative to placebo, catechin-caffeine mixtures stimulated fat oxidation above levels linked to caffeine alone [7,8], with three studies showing null effects [9][10][11]. High inter-individual variation was a common finding across these studies, with Rudelle et al. [10] reporting that six of 31 study participants did not respond with increased 24 h EE to the supplement dose (300 mg caffeine, 540 mg catechins, and 282 mg EGCG). ...
... Male participant numbers in metabolic chamber-based studies have been low (n = 10 to 15 per study), and only one study included females (n = 16) [10]. Study designs and dosing Nutrients 2019, 11, 2665 3 of 12 regimens have varied considerably, with two of the five studies including a 3 day supplementation period with measurements only on the third day [8,10]. ...
This randomized, double-blinded, crossover study measured the acute effect of ingesting a mixed flavonoid-caffeine (MFC) supplement compared to placebo (PL) on energy expenditure (EE) and fat oxidation (FATox) in a metabolic chamber with premenopausal women (n = 19, mean ± SD, age 30.7 ± 8.0 year, BMI 25.7 ± 3.4 kg/m2). The MFC supplement (658 mg flavonoids, split dose 8:30, 13:00) contained quercetin, green tea catechins, and anthocyanins from bilberry extract, and 214 mg caffeine. Participants were measured twice in a metabolic chamber for a day, four weeks apart, with outcomes including 22 h EE (8:30–6:30), substrate utilization from the respiratory quotient (RQ), plasma caffeine levels (16:00), and genotyping for the single-nucleotide polymorphism (SNP) rs762551. Areas under the curve (AUC) for metabolic data from the MFC and PL trials were calculated using the trapezoid rule, with a mixed linear model (GLM) used to evaluate the overall treatment effect. The 22 h oxygen consumption and EE were significantly higher with MFC than PL (1582 ± 143, 1535 ± 154 kcal/day, respectively, p = 0.003, trial difference of 46.4 ± 57.8 kcal/day). FATox trended higher for MFC when evaluated using GLM (99.2 ± 14.0, 92.4 ± 14.4 g/22 h, p = 0.054). Plasma caffeine levels were significantly higher in the MFC versus PL trial (5031 ± 289, 276 ± 323 ng/mL, respectively, p < 0.001). Trial differences for 22 h EE and plasma caffeine were unrelated after controlling for age and body mass (r = −0.249, p = 0.139), and not different for participants with the homozygous allele 1, A/A, compared to C/A and C/C (p = 0.50 and 0.56, respectively). In conclusion, EE was higher for MFC compared to PL, and similar to effects estimated from previous trials using caffeine alone. A small effect of the MFC on FATox was measured, in contrast to inconsistent findings previously reported for this caffeine dose. The trial variance for 22 h EE was not significantly related to the variance in plasma caffeine levels or CYP1A2*1F allele carriers and non-carriers.
... These findings are supported by different research, wherein wholesome volunteers received a green tea extract containing 270 -300 mg EGCG reduced the frame weight by means of 1.2% [31] to 1.5% [32]. In a randomized cross-over trial of Oolang tea, which contained 244 mg of EGCG and 270 mg of caffeine, fat oxidation additionally expanded by means of 12% above the manipulate amongst 12 wholesome volunteers, who consumed this tea day by day [79]. ...
... Specifically, the effect of green tea EGCG on EE and fat oxidation in human beings has obtained a lot of interest. Even as a few have located will increase in EE and fats oxidation by means of 4 and 35%, respectively, after supplementation with inexperienced tea extract containing 270 mg EGCG and 150 mg caffeine [74], others pronounced 2.nine% and 12% for the same parameters after ingesting Oolang tea containing 244 mg EGCG and 270 mg caffeine [79]. The overall fashion of elevated fat oxidation (3.3%) and thermogenesis (4.6%) in response to a beverage containing inexperienced tea EGCG (282 mg), calcium (633 mg) and caffeine (300 mg) is supported by Rudelle et al. [84]. ...
... The dosage of EGCG utilized in various research ranged from a hundred mg/day [31] to 540 mg/day [38], whilst the duration of the research various from someday to thirteen weeks [81]. The test objects had been administered both within the shape of tablets containing inexperienced tea extract up to 6tablets/day [74] or beverages at as much as 1500 ml/day [79]. the general fine results suggests that the choicest dose and period time for green tea catechins or EGCG administration lies with an affordable variety that may be easily integrated into a weight control programme. ...
... O chá proveniente das folhas da planta Camellia sinensis pode ser classificado em três tipos dependendo do grau de fermentação: chá verde, amplamente consumido em países da Ásia, não sofre fermentação durante seu processamento, mantendo desta forma a cor original das suas folhas; chá oolong, muito consumido na China, é parcialmente fermentado, resultando em uma chá verde-preto; e chá preto, muito popular na América do Norte e Europa, é mais fermentado do que o chá oolong, possuindo assim uma coloração mais escura e sabor característico [17][18][19]. ...
... Dentre as catequinas do chá verde, a EGCG é a mais abundante, constituindo cerca de um terço do seu peso seco total e a esta são atribuídas importantes propriedades contra o câncer, obesidade, diabetes e inflamações [18,19]. Este componente é considerado o maior componente bioativo para redução de peso, tendo como efeito a diminuição da diferenciação e proliferação dos adipócitos durante a lipogênese [23]. ...
Objetivo: O chá verde é rico em polifenois e sua utilização parece estar associada í redução da gordura corporal. O objetivo do estudo foi revisar a influência dos polifenois do chá verde na obesidade. Fonte de dados: Este artigo de revisão baseou-se em artigos selecionados por sua relevância, e provenientes de bases de dados como Science Direct, Pubmed, Bireme e Portal da Capes publicados entre 1992 e 2015. A busca contemplou as seguintes palavras-chave: polifenois, Camellia sinensis, perda de peso, obesidade. Síntese dos dados: O chá verde é uma bebida rica em polifenois, principalmente as catequinas, tendo como principal componente a epigalocatequina galato. Entre uma variedade de efeitos benéficos í saúde atribuídos ao consumo do chá verde, grande atenção tem sido dada aos seus efeitos anti-obesidade por promover aumento da oxidação de ácidos graxos, estimulação da lipólise e melhora da termogênese. Entretanto, os mecanismos de como o chá verde atua na redução de gordura corporal não estão completamente esclarecidos. Conclusão: O chá verde, aliado a um plano alimentar equilibrado, além da prática de atividade física, pode contribuir para melhora da obesidade.Palavras-chave: polifenois, Camellia sinensis, perda de peso, obesidade.
... However, the strength of such anti-obesity effects differs depending on the variety and functional components. Rumpler et al. observed that oolong tea extract intake significantly increased the energy expenditure in a group of young males (18). Since then, clinical trials have reported the effects of tea preparations on increasing energy expenditure, fat oxidation, weight loss, fat mass, and weight maintenance after weight loss (19)(20)(21). ...
... Since then, clinical trials have reported the effects of tea preparations on increasing energy expenditure, fat oxidation, weight loss, fat mass, and weight maintenance after weight loss (19)(20)(21). Oolong tea extracts decreased weight and body fat gain in rodent models in several studies (18,22). Kuo in tea-leaf-fed groups in the following order: oolong tea > pu-erh tea > black tea > green tea (23). ...
Background
Several studies have evaluated the effects of oolong tea extracts on obesity. However, only few studies focused on the anti-obesity effect of specific components of oolong tea.
Objective
This study investigated the specific anti-obesity capabilities of oolong tea polysaccharide (TPS) and tea polyphenols (TPP) in high-fat diet-induced Sprague–Dawley rats.
Methods
Oolong tea water extract, TPS, TPP, and polysaccharide mixed with polyphenol (TPSM) given at doses of 400 or 800 mg/kg were administered to rats fed with high-fat diet for 6 weeks to explore the anti-obesity effects of the treatments.
Results
TPS and TPP were responsible for the suppressive effect on body fat accumulation. TPSM exhibited the highest effect on body weight reduction, and TPS and TPP effectively reduced serum leptin levels and significantly improved blood lipid and antioxidant levels. Moreover, microarray analysis of hepatic and adipose gene expression profiles revealed that TPP and TPS inhibited obesity through effects on the pathways of fatty acid biosynthesis, steroid hormone biosynthesis, unsaturated fatty acid biosynthesis, fatty acid elongation, glycerolipid metabolism, and glycerophospholipid metabolism.
Conclusions
TPSM might be a potential therapy for the treatment of obesity.
... An increase in the EE in response to the consumption of different doses of caffeine, compared with green or oolong tea products was observed. Further, regression analysis suggested that the intake of caffeine-containing products associated with EGCG promotes an even greater increase in the EE, when compared to caffeine alone [77,[82][83][84]. ...
... Taken together, these data suggest the possibility that, in humans, the thermogenic effects of green tea reside in the synergistic interactions between catechins, caffeine and sympathetic release of NA [81]. Additionally, it has been observed that green tea products containing caffeine and catechins reduced the respiratory quotient (indicative of increased fat oxidation) [77,82,83,88]. The thermogenic effects of green tea might be, at least in part, related with the increase in fat oxidation, which contributes to both, the effectiveness on abdominal fat loss observed in clinical trials [89,90], and weight loss maintenance [91]. ...
Obesity is a health problem worldwide, and energy imbalance has been pointed out as one of the main factors responsible for its development. As mitochondria are a key element in energy homeostasis, the development of obesity has been strongly associated with mitochondrial imbalance. Polyphenols are the largest group of phytochemicals, widely distributed in the plant kingdom, abundant in fruits and vegetables, and have been classically described as antioxidants owing to their well-established ability to eliminate free radicals and reactive oxygen species (ROS). During the last decade, however, growing evidence reports the ability of polyphenols to perform several important biological activities in addition to their antioxidant activity. Special attention has been given to the ability of polyphenols to modulate mitochondrial processes. Thus, some polyphenols are now recognized as molecules capable of modulating pathways that regulate mitochondrial biogenesis, ATP synthesis, and thermogenesis, among others. The present review reports the main benefits of polyphenols in modulating mitochondrial processes that favor the regulation of energy expenditure and offer benefits in the management of obesity, especially thermogenesis and mitochondrial biogenesis.
... Polyphenols of tea are powerful antioxidants and could decrease LDL oxidation (40). Green tea may increase energy expenditure and ability to maintain body fat of individuals (41). Green tea also plays a role in thermogenesis and fat oxidation and thus has the potential effect to influence body weight (41). ...
... Green tea may increase energy expenditure and ability to maintain body fat of individuals (41). Green tea also plays a role in thermogenesis and fat oxidation and thus has the potential effect to influence body weight (41). Soya is a rich source of protein, fiber, vitamins, minerals, and isoflavonoids, and has low saturated fat content, which can reduce total cholesterol, LDL and inflammatory markers (1). ...
Background:
There are no investigations regarding the effects of consuming low-energy-dense diets rich in multiple functional foods on weight-loss maintenance, inflammatory markers, and cardiovascular disease (CVD) risk factors simultaneously.
Method:
This randomized controlled trial design was conducted on 90 men and women who were under a previous weight loss diet. Three months of intervention with recruitment at Allzahra Hospital, Isfahan, Iran, was done. Intervention was conducted following achieving 7-11 kg weight loss. Participants were encouraged to consumed these three: an isocaloric control diet (50% of energy from carbohydrate, 35% from fat, 15% from protein), a low-glycemic-index diet (LE) (60% from carbohydrate, 25% from fat, and 15% from protein), and a low-glycemic-index diet rich in multiple functional foods (LE + FF) (60% from carbohydrate, 25% from fat, and 15% from protein). Fasting blood glucose, serum insulin level, lipid profiles, inflammatory markers, adiponectin, systolic and diastolic blood pressure, and anthropometric measurements were assessed using standard guidelines.
Results:
The percent changes of weight, waist, and body mass index (BMI), systolic and diastolic blood pressure, malondialdehyde (MDA), high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor (TNF) α, total cholesterol, low-density lipoprotein (LDL) cholesterol, triglyceride, and fasting blood glucose (FBS) were substantially more decreased in the LE + FF group compared to the LE and control groups (p ≤ 0.03). Percent change of adiponectin among the LE + FF group was significantly more enhanced (7.29 ± 0.10) compared with the LE group (1.28 ± 0.20) (p = 0.001). Significantly more increment in the percent change of total antioxidant capacity (TAC) (6.91 ± 0.10) was obtained among the LE + FF group compared to the LE group (1.79 ± 0.04).
Conclusions:
This study provides established evidence supporting the beneficial effects of a low-energy-dense diet rich in multiple functional foods diet on improving weight-loss maintenance, inflammation, and cardiovascular risk factors.
... However, the strength of such anti-obesity effects differs depending on the variety and functional components. Rumpler et al. observed that oolong tea extract intake significantly increased the energy expenditure in a group of young males (18). Since then, clinical trials have reported the effects of tea preparations on increasing energy expenditure, fat oxidation, weight loss, fat mass, and weight maintenance after weight loss (19)(20)(21). ...
... Since then, clinical trials have reported the effects of tea preparations on increasing energy expenditure, fat oxidation, weight loss, fat mass, and weight maintenance after weight loss (19)(20)(21). Oolong tea extracts decreased weight and body fat gain in rodent models in several studies (18,22). Kuo in tea-leaf-fed groups in the following order: oolong tea > pu-erh tea > black tea > green tea (23). ...
Background: Several studies have evaluated the effects of oolong tea extracts on obesity. However, only few studies focused on the anti-obesity effect of specific components of oolong tea. Objective: This study investigated the specific anti-obesity capabilities of oolong tea polysaccharide (TPS) and tea polyphenols (TPP) in high-fat diet-induced Sprague–Dawley rats. Methods: Oolong tea water extract, TPS, TPP, and polysaccharide mixed with polyphenol (TPSM) given at doses of 400 or 800 mg/kg were administered to rats fed with high-fat diet for 6 weeks to explore the anti-obesity effects of the treatments. Results: TPS and TPP were responsible for the suppressive effect on body fat accumulation. TPSM exhibited the highest effect on body weight reduction, and TPS and TPP effectively reduced serum leptin levels and significantly improved blood lipid and antioxidant levels. Moreover, microarray analysis of hepatic and adipose gene expression profiles revealed that TPP and TPS inhibited obesity through effects on the pathways of fatty acid biosynthesis, steroid hormone biosynthesis, unsaturated fatty acid biosynthesis, fatty acid elongation, glycerolipid metabolism, and glycerophospholipid metabolism. Conclusions: TPSM might be a potential therapy for the treatment of obesity.
... Some possible explanations include reduced fat absorption, inhibition of pre-adipocyte differentiation and proliferation, and stimulation of lipolysis and apoptosis of existing adipocytes 1, 4-6 . Recent human studies suggest that underlying mechanisms associated with the anti-obesity effects of phytochemicals may be partly attributable to increased fatty acid oxidation 7, 8 . ...
... Dulloo and colleagues 7 found that supplementing with green tea extract for 24 h increases resting fatty acid oxidation by 9.9%. Moreover, Rumpler et al. 8 showed that intake of catechin-rich oolong tea for three days increases fatty acid oxidation by 12%. In agreement with those findings, Gahreman et al. 29 found that fatty acid oxidation is significantly increased after supplementing with catechin-rich green tea extract containing 187.5 mg polyphenols and 125 mg EGCG for one day. ...
[Purpose]
The purpose of this review is to discuss current views regarding the acute effects of phytochemicals, exercise, and exercise plus phytochemicals on fatty acid oxidation.
[Methods]
Data acquired from human and animal studies were comprehensively assessed to determine the single and combined effects of phytochemicals and exercise on fatty acid oxidation. In addition, underlying mechanisms associated with those conditions that may contribute to the regulation of fat metabolism are discussed.
[Results]
Although not all phytochemicals are effective at increasing fatty acid oxidation, some significantly improve the rate of fatty acid oxidation at rest. In addition, dietary supplementation of p-synephrine, catechins, or anthocyanins in combination with moderately intense exercise has the additive effect of increasing fatty acid oxidation, but not total energy expenditure during exercise.
[Conclusion]
The data reported from current reviewed studies suggest positive outcomes regarding facilitation of fatty acid oxidation from the combined effects of certain phytochemicals with exercise. Those data provide new insight for developing a strategy to boost fat loss and control weight in obese patients.
... Therefore, genes encoding the molecular components of this system might play a role in the development of obesity and related disorders [99], including leptin, the leptin receptor, POMC, and the melanocortin 4 receptor [100]. Among the components of oolong tea, caffeine is recognised as a particularly potent anti-obesity agent [101]. Research has shown that caffeine can decrease food intake [102] and enhance thermogenesis, thereby contributing to weight loss [103]. ...
Obesity has become a global health concern, with its prevalence steadily increasing in recent decades. It is associated with numerous health complications, including cardiovascular diseases, diabetes, and certain types of cancer. The aetiology of obesity is multifactorial, involving genetic, environmental, and lifestyle factors. In recent years, oxidative stress has emerged as a potential contributor to obesity and its related metabolic disorders. Dietary antioxidants, which can counteract oxidative stress, have gained significant attention for their potential role in preventing and managing obesity. This comprehensive review aims to explore the impact of dietary antioxidants on obesity and its associated metabolic dysregulations, discussing the underlying mechanisms and highlighting the potential therapeutic implications.
... Theasinensin is one of the active compounds in oolong tea, which has been shown to have high antiinflammatory activity by reducing the levels of pro-inflammatory mediators such as interleukins and tumor necrosis factors [8,9]. Due to the presence of theasinensin, oolong tea is a potential drug for obesity and fatty liver because of its inhibitory action on pancreatic lipase activity and the enhancing effect of caffeine on noradrenaline-induced lipolysis in adipose tissue [10,11]. Oolong tea extract also has high anti-cariogenic activity [10,12] and is effective against cardiovascular diseases [13]. ...
Background:-
Camellia sinensis, or oolong tea, is a partially fermented version of tea used in Asian countries. The remarkable reduction activity of the tea extract can potentially be used for synthesizing nanoparticles. Recently, Camellia sinensis has gained popularity for the formulation of some metal nanoparticles.
Aim
To formulate green synthesis of copper oxide nanoparticles (CuONPs) mediated by Camellia sinensis (oolong tea) and assess its cytotoxicity and antioxidant properties.
Materials & Methods
Oolong tea extract is prepared and added to CuSO4 solution to synthesize CuO nanoparticles (CuONPs). The centrifugation pellet of CuONPs is collected and subjected to DPPH (2,2 - diphenyl -1- picrylhydrazyl hydrate) and H2O2 assays. The cytotoxicity screening is performed using zebrafish embryos.
Results
The reducing activity of oolong tea successfully synthesizes the copper nanoparticles. High values are obtained in DPPH (63% inhibition at 10µL concentration, 73% inhibition at 20µL, 80% at 30µL, 85% at 40µL and 90% at 50µL concentrations) and H2O2 (50% inhibition at 10µL concentration, 65% at 20µL, 68% at 30µL, 75% at 40µL and 80% at 50µL concentrations) assays. There are no morphological deformities in the zebrafish and no loss of cell viability or delayed hatching at low concentrations (below 4-8 µL), as shown by the viable embryos with no morphological deformities.
Conclusion
The study has evidenced high antioxidant activity and minimal cytotoxicity of CuO nanoparticles produced using Camellia sinensis, thus proving it to be a good biomaterial for a wide range of biological applications.
... Oolong tea is a semi-fermented tea produced from green shoots of a variety of tea plants and is worldwide considered a health drink. The frequent consume of oolong tea has been associated with alleviating cardiovascular disease, cancer and obesity [151]. Therefore, lipase inhibitors present in oolong tea were investigated using an affinity-based screening method [152]. ...
Enzyme inhibitors represent a substantial fraction of all small molecules currently in clinical use. Therefore, the early stage of drug-discovery process and development efforts are focused on the identification of new enzyme inhibitors through screening assays. The use of immobilized enzymes on solid supports to probe ligand-enzyme interactions have been employed with success not only to identify and characterize but also to isolate new ligands from complex mixtures. Between the available solid supports, magnetic particles have emerged as a promising support for enzyme immobilization due to the high superficial area, easy separation from the reaction medium and versatility. Particularly, the ligand fishing assay has been employed as a very useful tool to rapidly isolate bioactive compounds from complex mixtures, and hence the use of magnetic particles for enzyme immobilization has been widespread. Thus, this review provides a critical overview of the screening assays using immobilized enzymes on magnetic particles between 2006 and 2021.
... These results may also be related to theobromine and other methylxanthines present in chocolate that have been shown to increase thermogenesis and lipid oxidation, 39 or to flavanols (epicatechin or catechin), other foods or beverages with similar contents of epicatechin or catechin that have been shown to increase fat oxidation. 40 As adipose tissue contributes to lipid oxidation, 41 these differences in substrate oxidation may be accounting for the decrease in waist circumference when chocolate was eaten in the morning. Literature shows that good weight loss responders have higher lipid oxidation rates than those experiencing weight relapse, 42 and reduced lipid to carbohydrate oxidation ratio represents the most important factor (more important than other behavioral and physiological factors) in regaining body weight following successful weight loss. ...
Eating chocolate in the morning or in the evening/at night, may differentially affect energy balance and impact body weight due to changes in energy intake, substrate oxidation, microbiota (composition/function), and circadian‐related variables. In a randomized controlled trial, postmenopausal females (n = 19) had 100 g of chocolate in the morning (MC), in the evening/at night (EC), or no chocolate (N) for 2 weeks and ate any other food ad libitum. Our results show that 14 days of chocolate intake did not increase body weight. Chocolate consumption decreased hunger and desire for sweets (P < .005), and reduced ad libitum energy intake by ~300 kcal/day during MC and ~150 kcal/day during EC (P = .01), but did not fully compensate for the extra energy contribution of chocolate (542 kcal/day). EC increased physical activity by +6.9%, heat dissipation after meals +1.3%, and carbohydrate oxidation by +35.3% (P < .05). MC reduced fasting glucose (4.4%) and waist circumference (−1.7%) and increased lipid oxidation (+25.6%). Principal component analyses showed that both timings of chocolate intake resulted in differential microbiota profiles and function (P < .05). Heat map of wrist temperature and sleep records showed that EC induced more regular timing of sleep episodes with lower variability of sleep onset among days than MC (60 min vs 78 min; P = .028). In conclusion, having chocolate in the morning or in the evening/night results in differential effects on hunger and appetite, substrate oxidation, fasting glucose, microbiota (composition and function), and sleep and temperature rhythms. Results highlight that the “when” we eat is a relevant factor to consider in energy balance and metabolism.
... Amino acids contribute to sweetness, and caffeine and catechins are responsible for the bitter and astringent taste [3]. A list of beneficial effects of oolong tea include antioxidant, anti-obesity, anticancer, anti-microbial and antihyperglycemic activities [4][5][6][7][8]. The chemical composition and quality of oolong tea are affected by climate, the plant age, production methods and nitrogen (N) fertilization [9,10]. ...
Oolong tea, one of the most famous tea beverages in China, contains specialized metabolites contributing to rich flavors and human health. Accumulation patterns of such metabolites and underlying regulatory mechanisms significantly vary under different growth conditions. To optimize quality and yield while minimizing environmental effects, three treatments were designed in this study: Conventional fertilization, optimized fertilization, and optimized fertilization supplemented with magnesium (Mg). We investigated the yield, taste quality, primary and secondary metabolites of oolong tea, and found that a substantial reduction in chemical fertilizers (nutrient optimization by reducing 43% N, 58% P2O5 and 55% K2O) did not affect the tea yield in this study. Interestingly, Mg fertilization is an important factor influencing amino acid and sugar accumulation in oolong tea, resulting in higher concentrations of total free amino acids and a lower ratio of tea polyphenols (TP) to free amino acids (FAA). Gas chromatography-time-of-flight mass spectrometry (GC-TOF-MS) and liquid chromatography-high resolution mass spectrometry (LC-HRMS) combined multivariate analyses revealed distinct features of metabolite accumulation in leaves of three different treatments, as indicated by 34 differentially accumulated characteristic compounds. The levels of serine, aspartic acid, isoleucine, phenylalanine, theanine, and proline were reduced by fertilizer optimization and increased by Mg supplementation. Mg particularly promoted theanine accumulation favoring a stronger umami taste of oolong tea, while decreasing astringency and bitter metabolites. Thus, Mg application paves a new path for tea quality improvement in Southern China where Mg deficiency in the soil is a frequent limiting factor for crop production.
... Some of the possible rudimentary justification for obese condition may be inhibition of absorption of fat, impediment of pre-adiposyte differentiation, lipolysis stimulation and induction of apoptosis of adipocytes [63]. Oxidation of fatty acids by phytochemicals may be another reason for their beneficial effects [81,82]. ...
... Concerning flavonoids and lignans, sesamin (a lignan) has been reported to be a potent inducer of hepatic FA oxidation in 10-15% fat fed rats (Ashakumary et al., 1999;Ide et al., 2001), and the flaxseed lignan secoisolariciresinol (SECO) was recently shown to dose-dependently reduce hepatic lipid accumulation in high-cholesterol fed rats (Felmlee et al., 2009). Major green tea polyphenols (e.g., (−)-epigallocatechin-3-gallate) may prevent fatty liver disease in high-fat fed mice (Bose et al., 2008), and various types of flavonoids have been shown to prevent liver steatosis (Dulloo et al., 1999;Sachan and Hongu, 2000;Rumpler et al., 2001;Klaus et al., 2005;Shimotoyodome et al., 2005;Venables et al., 2008). The mechanisms involved would be the ability of polyphenols to down-regulate and upregulate the gene expression of lipogenic and FA oxidation enzymes, respectively, and their resulting activities, and also the ability to increase PPARα and decrease SREBP gene expression ( Figure 2D and Supplemental Table 2). ...
... Some bacterial genera (Acidaminococcus, Anaerobiospirillum, Anaerovibrio, Bacteroides, Blautia, Catenibactetium, Citrobacter, Clostridium, Collinsella, and Escherichia) were significantly associated with body weight; thus, we hypothesize that modulation of the intestinal microbiota is the mechanism by which GTPs consumption ameliorates high-fatdiet-induced obesity. Chronic systemic inflammation directly contributes to the development of obesity [53][54][55][56]. Obese subjects usually have elevated serum levels of inflammatory cytokines, such as IL-6 and TNF-α [57,58]. ...
Green tea polyphenols (GTPs) exhibit beneficial effects towards obesity and intestinal inflammation; however, the mechanisms and association with gut microbiota are unclear. We examined the role of the gut microbiota of GTPs treatment for obesity and inflammation. Canines were fed either a normal diet or high-fat diet with low (0.48% g/kg), medium (0.96% g/kg), or high (1.92% g/kg), doses of GTPs for 18 weeks. GTPs decreased the relative abundance of Bacteroidetes and Fusobacteria and increased the relative abundance of Firmicutes as revealed by 16S rRNA gene sequencing analysis. The relative proportion of Acidaminococcus, Anaerobiospirillum, Anaerovibrio, Bacteroides, Blautia, Catenibactetium, Citrobacter, Clostridium, Collinsella, and Escherichia were significantly associated with GTPs-induced weight loss. GTPs significantly (P<.01) decreased expression levels of inflammatory cytokines, including TNF-α, IL-6, and IL-1β, and inhibited induction of the TLR4 signaling pathway compared with high-fat diet. We show that the therapeutic effects of GTPs correspond with changes in gut microbiota and intestinal inflammation, which may be related to the anti-inflammatory and anti-obesity mechanisms of GTPs.
... Tea contains a rich amount of caffeine and possesses anti-lipase effects to confer obesity prevention (Rumpler et al., 2001;Tanaka et al., 2010). However, most of the included studies indicated that caffeine showed a very weak effect in vitro against pancreatic lipase with IC 50 > 50 µM (Nakai et al., 2005;Cha et al., 2012;Yuda et al., 2012). ...
Losing weight has significant impact on chronic disease management. Orlistat, a lipase inhibitor, has alternative effect for weight controlling. To find more candidates, we conducted a review of chalcone and xanthine derivatives regarding their anti‐lipase activity. Eight databases were searched including PubMed, Scopus, Web of Science (ISI), Virtual Health Library (VHL), System for Information on Grey Literature in Europe (SIGLE), Global Health Library (GHL), EMBASE, and Google Scholar in August 2018. We found chalcone scaffold was more effective on lipase inhibition than xanthine scaffold. Among 19 investigated chalcones, only isoliquiritigenin and licuroside demonstrated an effect on preventing weight‐gain and increase of in total cholesterol and total triglycerides aside apart from their high activity on inhibiting lipase. Effect and type of inhibition of individual chalcones differed depending on their structure. In addition, very few studies investigated xanthine compounds and their activities were inconsistent. We suggest more studies investigate the ability of chalcones and modifying their structure find out other compounds with higher efficacy. Our study found that compounds with chalcone scaffold are higher effective than xanthines. Amongst them, three chalcones, namely isoliquiritigenin, morachalcone A, methylenebisphloretin, are the most potential candidates with IC50 values < 10 µM. They could be non‐competition inhibitors or mixed‐type competitors. Some chalcones could make bonds with pancreatic lipase which can be a model for further studies in drug design. Compound with low absorption in the body could exhibit more effective than the others.
... Tea, another flavonoid-rich dietary component, has also been investigated for its ability to influence energy expenditure and substrate oxidation. Rumpler et al. [38] investigated the effects of oolong tea on measures of indirect calorimetry after noting weight loss interventions with oolong tea [39]. Twelve men consumed 1.5 L per day of full-strength oolong tea, a caffeine-matched positive water control, or a placebo water control in a crossover, randomized design for three days with a 23 hr stay in a room-sized calorimetry chamber on the third day. ...
Berries and other anthocyanin-rich treatments have prevented weight gain and adiposity in rodent models of diet-induced obesity. Their efficacy may be explained by modulation of energy substrate utilization. However, this effect has never been translated to humans. The objective of this study was to evaluate the effects of berry intake on energy substrate use and glucoregulation in volunteers consuming a high-fat diet. Twenty-seven overweight or obese men were enrolled in a randomized, placebo-controlled crossover study with two treatment periods. Subjects were fed an investigator controlled, high-fat (40% of energy from fat) diet which contained either 600 g/day blackberries (BB, 1500 mg/day flavonoids) or a calorie and carbohydrate matched amount of gelatin (GEL, flavonoid-free control) for seven days prior to a meal-based glucose tolerance test (MTT) in combination with a 24 h stay in a room-sized indirect calorimeter. The washout period that separated the treatment periods was also seven days. The BB treatment resulted in a significant reduction in average 24 h respiratory quotient (RQ) (0.810 vs. 0.817, BB vs. GEL, p = 0.040), indicating increased fat oxidation. RQ during the MTT was significantly lower with the BB treatment (0.84) compared to GEL control (0.85), p = 0.004. A 4 h time isolation during dinner showed similar treatment effects, where RQ was reduced and fat oxidation increased with BB (0.818 vs. 0.836, 28 vs. 25 g, respectively; BB vs. GEL treatments). The glucose AUC was not different between the BB and GEL treatments during the MTT (3488 vs. 4070 mg·min/dL, respectively, p = 0.12). However, the insulin AUC was significantly lower with the BB compared to the GEL control (6485 vs. 8245 µU·min/mL, p = 0.0002), and HOMA-IR improved with BB (p = 0.0318). Blackberry consumption may promote increased fat oxidation and improved insulin sensitivity in overweight or obese males fed a high fat diet.
... Support for this contention includes a controlled human trial that showed weight loss when tea was added to a dietary regimen [10] and a mouse study that showed that administration of a tea extract with a high-fat diet eliminated the weight gain observed in the absence of tea [11]. Modest increases in energy expenditure have been reported with the ingestion of oolong and green teas [12,13]. Green tea consumption has been linked to lowering of various forms of cancers [14,15]. ...
Tea is largest consuming drink in the world. Many health claims is attributed towards the tea due to its distinguished phytochemical array. Role of tea is well established as a neutraceutical and many studies elucidate its pharmacological worth. The objective of this study was to calculate the calorie content by determining total lipid, crude fiber, total protein and available carbohydrate contents and estimation of caffeine and niacin content in Bangladeshi teas. The lipid, crude fiber, protein and available carbohydrate contents of the tea samples were found to be in the range of 3.25-5.53, 10.15-15.41, 12.97-17.08 and 4.78-6.21 g/100g fresh weight respectively while calorie contents were found in the range of 83.54- 101.46 Kcal/100g fresh weight of tea. The total caffeine and niacin content in teas ranged from 1.31 - 3.58 and 0.038 – 0.056 g/100g fresh weight respectively. Tea leaf contained the highest amount of caffeine (3.58 g/100g) and niacin (0.056 g/100g). As tea has different health effects it is essential to estimate the update nutrient contents of tea.
... Studies have identified that purple tea also regulated weight gain by inhibiting fat absorption and enhancing hepatic fat metabolism [28]. Several randomized controlled trials in humans demonstrated that Oolong tea may increase energy metabolism, metabolic rate, and fat oxidation [135][136][137], as shown for black and green tea. Studies further acknowledged that fully fermented black tea leaves and partially fermented oolong tea leaves were more effective on growth suppressive and hypolipidemic properties compared to the nonfermented green tea leaves [138], indicating the importance of fermentation. ...
... For meta-analysis, in addition to BMI, WC and TBFM, the parameters EE, RQ and FOX rate were also included in this systematic review and meta-analysis. They were included because they are important diagnostic indicators of fat metabolism, which is considered a major risk factor for overweight and obesity [19,21,[56][57][58]. ...
... In human studies, clear increases in energy expenditure were documented 17 . Also, some suggested the protective function of EGCg for cytokine-induced β-cell destruction mediated by inhibition of nuclear factor-κ B activation 20 . Recently, Tian and associates demonstrated that tea polyphenols had anti-obesity effect by up-regulating adiponectin levels in rats 21 . ...
Black tea consumption has been popular widely across the world. Tea (Camellia sinensis) has been used as a daily beverage since time immemorial. Tea is mainly available in three variants, approximately 76% to 78% of the tea produced and consumed worldwide is black, 20-22% is green and less than 2% is oolong. Tea is an excellent source of polyphenolic compounds, particularly flavonoids. The active components of tea responsible for such biological effects are known to be catechins (known as polyphenols), which constitute seven forms including epigalocatechingallate (EGCg). EGCg is a major catechin compound present in tea extracts and is also the most active form in a variety of biological activities .]. The purpose of this review will focus on the effect of black tea catechins extracted from the Camellia sinensis plant on type 2 diabetes and metabolic syndrome. It is hoped that black tea can be consumed in a suitable manner as a supplement to prevent the progression of type 2 diabetes along with imparting other health benefits as well.
... Previous reports have shown that bioactive components present in some teas (catechin and epigallocatechin-3-gallate) are capable of enhancing weight loss [42,43]. Furthermore polyphenols such as L-epicatechin, epicatechin-3-gallate, epigallocatechin, epigallocatechin-3-gallate which were isolated from tea extracts are potent inhibitors of pancreatic lipase which contributes to weight loss [44,45]. ...
Abstract Review Article
Obesity is a chronic, multifactorial condition with complex metabolic and behavioral causes and consequences. Epidemiological studies have shown that obesity contributes to the increase in mortality from cancers of the colon, breast (in postmenopausal women), endometrium, kidney (renal cell), esophagus (adenocarcinoma), gastric cardia, pancreas, gallbladder and liver and possibly other types while some experimental investigations have revealed that obesity is a major risk factor for type 2 diabetes, atherosclerosis, cancer and other chronic diseases. Factors such as high caloric intake, genetic factors
and psychological factors can lead to obesity. Furthermore, pharmaceuticals, sleep duration, environmental temperature and endocrine disruptors have been established to also be a causative factor of obesity. The therapeutic approach for the treatment of obesity involves different mechanisms and strategies. Plant based
diets are increasingly being recognized for their health benefits in weight management, satiety effects and glycemic control. Therefore, dietary agents that have a potential to decrease body fat or improve hyperglycemia may be used as therapeutic agents for the treatment and/or management of obesity. This review therefore focus on the role of functional foods and nutraceuticals in the treatment and/or management of obesity.
... Increase of energy metabolism is another proposed mechanism of oolong tea and OTPPs that explain how they could reduce body weight and modulate lipid profile. A randomized crossover study performing with normal weight Japanese men reported that 24-h energy expenditure of men receiving oolong tea [35]. In this study, subjects were given either water, full-strength tea (15 g of tea in 1500 mL/day), half-strength tea (7.5 g of tea in 1500 mL/day) or water containing 270 mg caffeine, equivalent to the concentration in the full-strength tea treatment. ...
In this alphabetically arranged chapter, supplements from Maca through Pyridoxine (Vitamin B6) are discussed in detail. For each supplement, this chapter defines what it is and how it works in the body. Further, this chapter discusses the supplement’s recommended dosage as well as the evidence for or against its different usages. Safety concerns, side effects, and precautions are next discussed as well as any potential interactions with other medications. References are provided for the data provided. The goal is for the healthcare provider to be able to reference each supplement and come away with a full, balanced, evidence-based understanding of these topics.
Noncommunicable diseases (NCDs) are one of the major public health concerns globally. Most of the NCDs including insulin resistance, metabolic syndrome, type 2 diabetes mellitus, fatty liver disease, and coronary heart disease are related to obesity and are called obesity-related NCDs (OR-NCDs). However, adipocytes can reduce OR-NCDs by secreting adiponectin. Adiponectin has an inverse relationship with body fat. Obese people have impairment in differentiating pre-adipocytes to adipocytes, the process facilitated by adiponectin. Adiponectin directly increases insulin sensitivity and reduces obesity-related insulin resistance by down-regulating hepatic glucose production and increasing fatty acid (FA) oxidation in skeletal muscle. Considering the various beneficial effects of adiponectin on health, increasing adiponectin might be a promising approach to prevent and treat OR-NCDs. Recent studies have shown that nutraceuticals and medicinal compounds isolated from plants could prevent and treat various diseases, particularly cardiovascular diseases (CVDs), diabetes mellitus, obesity, and non-alcoholic fatty liver disease. However, to our knowledge, the effect of these natural products, including herbal supplements and functional foods on adiponectin, has not yet been fully reviewed. The main aim of this review is to summarize the effects of nutraceuticals and herbal bioactive compounds on plasma adiponectin concentrations based on clinical studies. It can be concluded that medicinal plants, and herbal bioactive compounds, particularly curcumin, anthocyanins, resveratrol, soy, walnut, and dihydromyricetin can be used as adjunct or complementary therapeutic agents to increase plasma adiponectin, which could potentially prevent and treat NCDs.
Background:
Research indicates that diets enriched with unsaturated fatty acids improve energy metabolism, although studies on tree nuts, which are a rich source of those fats, are limited. The present study aimed to examine the impact of daily pecan consumption for 8 weeks on energy metabolism in adults with hypercholesterolaemia or at higher risk for cardiovascular disease (CVD) (body mass index ≥ 28 kg m-2 ).
Methods:
For this randomised, controlled trial, 56 sedentary adults were randomised into one of three treatments for an 8-week intervention: two pecan groups and a nut-free control group (n = 18). The ADD group (n = 16) consumed pecans as part of a free-living diet, whereas the SUB group (n = 18) substituted the pecans for isocaloric foods from their habitual diet. At baseline and 8 weeks, a high saturated fat meal was consumed along with indirect calorimetry measurements at fasting and for 4 h postprandially to determine changes in resting metabolic rate (RMR), diet induced thermogenesis (DIT) and substrate utilisation (primary outcomes). Forty-seven participants completed the trial and were included in analyses.
Results:
In the SUB group, there was an increase in fasting RMR (1607 ± 117 to 1701 ± 114 kcal day-1 ; p = 0.01) and fasting fat oxidation (0.83 ± 0.08 to 0.99 ± 0.08 g/15 min; p = 0.009) and a decrease in fasting respiratory exchange ratio (0.85 ± 0.01 to 0.83 ± 0.01; p = 0.05) from pre- to post-intervention. In the ADD group, there was an increase in postprandial DIT (p < 0.001). There were no changes within the control group or between groups for any outcome measure.
Conclusions:
Daily consumption of pecans may increase select measures of energy expenditure and fat oxidation in adults at-risk for CVD.
The purpose of the OsTea translational study was to assess the efficacy of teas (tulsi, rooibos, oolong) compared to placebo (coriander) on markers of bone health and quality of life (QOL) in those with osteopenia and on human mesenchymal stem cell (hMSC) differentiation into osteoblasts to identify potential mechanisms of action. Following consumption of tea (3 times/day; 90 days), participants collected a urine sample during the night (10pm-6am) and filled in questionnaires before and after the study. Rooibos consumption demonstrated a significant decrease in urinary CTX levels vs placebo; trended towards increases in nocturnal melatonin levels (p=0.06); significantly decreased serotonin-producing microbes in the gut; and demonstrated trends towards improvements (p=0.09) in QUALIOST emotional parameters. Tulsi consumption primarily affected subjective measures, such as significantly improved scores for PSS, STAI-trait anxiety, and osteoporosis/osteopenia-related parameters in the QUALIOST. To further identify potential mechanisms underlying these actions of rooibos on CTX and melatonin (urinary and gut), rooibos and melatonin effects on human osteoblastogenesis were carried out for 21 days under oxidative stress conditions to mimic osteopenia. Although both rooibos and melatonin protected against oxidative stress-induced loss of osteoblasts in vitro, their underlying mechanisms were different. Melatonin, like tulsi and oolong, demonstrated the greatest protection against oxidative stress at days 10-11 of exposure, which was due to effects on hMSC viability and through melatonin receptors. Rooibos, on the other hand, demonstrated protection at days 10-11 and 20-21, which was through signaling mechanisms involved in differentiation processes and not on cell viability. These findings suggest that the clinical actions of rooibos on decreasing CTX levels in a population with osteopenia may be through a cooperative effort between melatonin and rooibos by protecting hMSC viability against oxidative stress-induced loss and by promoting osteoblast differentiation, respectively. This study also supports the use of tulsi for improving quality of life in a population susceptible to osteoporosis.
Pu-erh tea is one of the most popular beverages in China and Southeast Asia, however, influences from fermentation and storage on its chemical profile and quality are unclear. Thus, bioactivities and metabolomes of raw (17-raw) and ripened teas (17-rip through 06-rip) were assessed using chemical methods and a UPLC-QQQ-MS-based metabolomic approach. Results evidence that chemical components and antioxidant activities of 17-rip through 06-rip were similar but lower than those of 17-raw. Subsequently, 842 metabolites were identified from 17-raw, 17-rip and 06-rip, of which 20 and 19 metabolites were biomarkers for discerning 17-rip from 17-raw and 06-rip, respectively. Between 17-raw and 17-rip, 536 differential metabolites were identified, and 17-rip contained higher levels of gallic acid, acetyl amino acids, purine alkaloids, pyrimidine alkaloids and non-glycoside flavonoids and lower levels of sour compounds, quinic acid derivatives, amino acids, flavonoids glycosides, and flavan-3-ols; all of them were found to be positively but gallic acid and acetyl amino acids negatively correlated with two tested bioactivities. Between 17-rip and 06-rip, 175 differential metabolites were identified, among which alkaloids positively correlated to the two bioactivities. Overall, this study identified biomarkers distinguishing teas with different fermentation processes and storage times and different metabolites affecting their tastes and bioactivities.
Tea and citrus maxima are natural, medicinal homologous plants, typically used for making beverages, which have anticancer, antiobesity, and antioxidation properties. Green tea, yellow tea, and black tea were combined with citrus maxima to obtain green tea and Citrus maxima (GTCM), yellow tea and Citrus maxima (YTCM), and black tea and Citrus maxima (BTCM). The biochemical components of these mixtures were analyzed, and their possible effects and mechanisms on relieving liver lipid deposition were explored. The tea polyphenols, free amino acids, phenolamine ratio, and caffeine were comparable in YTCM and GTCM, being significantly higher than those in BTCM. In addition, the content of esterified catechins, nonesterified catechins, and total catechins in YTCM was significantly higher than those in GTCM and BTCM. All three mixtures of Citrus maxima tea significantly reduced lipid deposition in HepG2 cells, with GTCM and YTCM being slightly more effective than BTCM. Regarding the possible mechanism, Western blot analysis revealed that the three Citrus maxima tea mixtures could activate the AMPK/ACC signaling pathway, upregulate the expression of p-AMPK, p-ACC, and CPT-1 proteins, and downregulate the expression of SREBP1c and fatty acid synthase proteins to inhibit fat synthesis, thereby relieving lipid deposition in liver cells. In conclusion, as a novel and healthy beverage, Citrus maxima tea has the potential to alleviate liver lipid deposition, and further could be responsible for obesity treatment.
There is increasing interest in the potential role of epigallocatechin gallate (EGCG) in changing body composition to lower body fat with increased lean mass. In this study, we examined the sex-dependent effect of EGCG on body composition, locomotion, feeding behaviour, sugar levels, and transcription levels of key regulators in lipid, carbohydrate, and energy metabolisms in Drosophila melanogaster. EGCG had no effects on body weights in both females and males, but decreased fat accumulation in females compared to the control, accompanied by a reduction in food intake. EGCG treatments increased lean mass and locomotor activity, and downregulated transcription levels of brummer (bmm), adipokinetic hormone (akh), and Drosophila insulin-like peptide 2 (dilp2), and upregulated spargel (srl) in males. In addition, EGCG decreased sugar levels in both females and males. In conclusion, EGCG promotes lean phenotype in D. melanogaster via sex-specific metabolic regulations.
Tea (Camellia sinensis, Theaceae) is a popular beverage consumed worldwide. Green tea, oolong tea, and black tea are the three major tea types that are obtained through different levels of fermentation of the tea leaves. The health benefits of tea have been widely studied, and these effects are closely related to the structure and composition of polyphenols. In spite of growing evidences for health benefits of green tea, less research has been done using black and oolong teas, which are more widely consumed. This mini-review mainly focused on biological activities of oolong and black tea, and their characteristic polyphenols, i.e., oolong tea theasinensins, and black tea theaflavins. Several biological activities have been associated with tea consumption and polyphenol contents, including anticancer activities, antioxidant activities, anti-cardiovascular activities, antimicrobial activities, anti-hyperglycemic activities, and anti-obesity activities, suggesting the important roles of tea and tea polyphenols in human health and in disease prevention and treatment. However, application of tea polyphenols in the development of dietary interventions or alternative treatment approaches need to be aware of the low bioavailability and potential toxicity of tea polyphenols. Future studies to incorporate existing methods or develop new methods for enhancing polyphenol absorption will help to obtain these health benefits with a lower dose and prevent overdose toxicity.
Background: The prevalence of overweight was increasing dramatically worldwide. The aim of our study was to investigate the association of plain water intake (PWI) with the risk of new-onset overweight risk among Chinese adults.
Methods: A total of 3200 adults aged 18–65 who were free of overweight at baseline were enrolled from China Health and Nutrition Survey (CHNS) cohort study in 2006-2011. The risk of new-onset overweight with different amounts of PWI per day was analyzed in this five-year cohort. A multiple logistic regression model was used to assess the association of PWI and the risk of new-onset overweight and adjust for potential confounders. Moreover, dose-response models were developed to estimate the linear relationship.
Results: During 5 years of follow-up, 1018 incident cases were identified. Our analysis indicated an inverse association of more than 4 cups of PWI per day and the risk of new-onset overweight among normal weight individuals. Compared with participants who drank 2 to 3 cups PWI, the adjusted odds ratios (OR) of overweight were 0.741 (95% CI, 0.599-0.916) in participants who drank 4 to 5 cups PWI, and 0.547 (95% CI, 0.435-0.687) in participants who drank more than 6 cups PWI. The dose–response analysis showed that every cup of PWI was associated with a 6.5% and 8.4% decrease in the risk of new-onset overweight among men and women, respectively. The interactions of PWI and covariates on the risk of overweight were not found.
Conclusion: Drinking more than 4 cups (≈1 liter) per day of plain water is associated to decrease the risk of new-onset overweight among normal weight individuals.
Obesity is a condition of excess body fat. It is one of the most rapidly evolving public health issues in the recent years. According to the Centers for Disease Control and Prevention (CDC) [1,2] over two thirds of Americans are overweight, one third of Americans are obese, and one sixth of American children and adolescents are considered overweight or obese. The reported prevalence of obesity among adolescents has nearly tripled in the past two decades [1,2]. Obesity is not only a cosmetic issue but is also associated with several comorbidities and comortalities, including cardiovascular disease, type 2 diabetes, many forms of cancer, gallbladder disease, and osteoarthritis [3,4]. It is estimated that 400,000 deaths each year in the United States are associated with obesity [5].
Diabetes mellitus, characterized by hyperglycemia, is growing at an alarming rate. Tea is the most consumed beverages; it is next only to water. The chief chemical components of tea leaves are polyphenols (catechins and flavonoids), alkaloids (caffeine, theophylline, theobromine), polysaccharides, volatile oils, amino acids, lipids, vitamins (e.g. vitamin C), inorganic elements (e.g. aluminium, fluorine, manganese) etc. However, the polyphenols are mostly accountable for the therapeutic properties of tea. The type of polyphenols varies in different tea according to their process of manufacturing and fermentation. This current write up reviews the polyphenolic constituents of different types of tea and their in-vivo and in-vitro anti-diabetic properties.
Males seeking to improve body composition may ingest thermogenic dietary supplements with the goal of elevating resting metabolic rate. The purpose of this study was to examine the effects of a commercially available dietary supplement (containing ingredients that promote thermogenesis) on resting metabolic rate (RMR) in a randomized, double-blind, placebo-controlled cross-over study. Ten healthy, physically active males (age: 26.5 ± 6.4 years; height: 177.6 ± 7.2 cm; body weight: 80.5 ± 10.8 kg) underwent two testing sessions separated by approximately 7 days. Following baseline assessments of RMR, heart rate (HR), and blood pressure (BP), each participant ingested a thermogenic dietary supplement or a placebo. Assessments were repeated at 60, 120, and 180 minutes postingestion. Approximately 1 week later, participants ingested the alternative supplement and the assessments were repeated. Post hoc analyses revealed that the dietary supplement treatment demonstrated significant elevations in RMR during the postingestion period (p < 0.05) from 1,859 ± 266 kcal to 2,027 ± 288 kcal (increase of 9%) to 2,072 ± 292 kcal (increase of 11.5%) and to 2,040 ± 271 kcal (increase of 9.7%) at 60, 120, and 180 minutes postingestion, respectfully. No significant elevations were observed in the placebo treatment at any time point. HR and BP measures were within normal clinical values throughout the intervention.
Brewed tea (from the Camellia sinensis plant) is the second most commonly consumed beverage in the world, and its consumption has been associated with several human health benefits. Tea polyphenols are absorbed in the intestine following consumption and metabolized by both human and microbial systems to yield a mixture of complex metabolites that can be found in circulation and throughout the body. Identification of tea phenolic constituents and their metabolites has served to strengthen the association between tea consumption and specific health benefits, as well as to measure potential differences between tea product forms. The current state of research suggests that long-term consumption of tea and tea polyphenols may provide distinct health benefits, with the strongest associations being the promotion of cardiovascular health, as well as antidiabetic and antiobesity effects. However, much regarding tea and health remains to be discovered. This includes development of a better understanding of the role of abundant oxidized polyphenol forms in oolong and black tea, whose bioavailability and specific role in health benefits remain unknown. This technical summary focuses on tea polyphenol bioaccessibility/bioavailability, discusses potential bioactivity, and highlights studies that link tea consumption and health.
Background
The anti-obesity potential of flavonoids has been shown by animal and human studies. In this meta-analysis, we systematically reviewed controlled clinical trials and quantified the effects of flavonoids and flavonoid subclasses on obesity-related anthropometric measures.
Methods and results
PubMed, EMBASE, Scopus, Web of Science, and ProQuest databases were searched to identify trials examining the effect of flavonoids on body mass index (BMI), waist circumference, and body fat percentage. Fifty eight trials passed the eligibility process. Analysis endpoints were calculated as the mean difference between baseline and post-treatment. Flavonoids were in subclasses of flavanols, flavonols, isoflavones, flavanones, anthocyanins, and proanthocyanidins. They were mostly in the form of supplements and dosages varying from 40 to 1300 mg/day. Among flavonoid subclasses, flavanols showed potential for decreasing BMI, in the overall population (mean difference (MD) = -0.28 kg/m², P=0.04; n=21) and in the subgroups of Asians (MD = -0.42 kg/m²; P=0.046; n=13), ages < 50 years (MD = -0.50 kg/m²; P=0.008; n=14), BMI ≥ 25 kg/m² (MD = -0.30 kg/m²; P=0.049; n=15), and at doses ≥ 500 mg/day (MD = -0.36 kg/m²; P=0.049; n=12). Isoflavones also decreased BMI of non-Asian populations (MD = -0.26 kg/m²; P=0.035; n=13) and doses ≥ 75 mg/day (MD = -0.34 kg/m²; P=0.027; n=8). In the overall assessment, flavanols also decreased waist circumference (MD = -0.60 cm; P=0.02; n=18) but had no significant effect on body fat percentage. The available trials did not reveal significant effects from flavonols, flavanones, and anthocyanins on the specified anthropometric measures.
Conclusions
Overall results of this meta-analysis showed that flavanols have potential against obesity.
Obesity is a chronic disease of excess adiposity that affects approximately one-third of the adult population in the USA with a growing prevalence worldwide. Obesity has been one of the most challenging complex diseases because of the overwhelming influence of the obesogenic environment. Despite this challenging environment, lifestyle interventions for obesity can be successful at creating a negative energy balance, the cornerstone of obesity management. The methods of lifestyle therapy for obesity treatment can be individualized to target associated risk factors, enhance adherence to a treatment plan, and lead to sustained maintenance of weight loss. Using dietary modification, physical activity, and behavioral counseling, the practitioner can address the physiological and behavioral underpinnings that contribute to calorie imbalance and excess weight gain. This chapter reviews the components of effective and individualized lifestyle therapy strategies to prevent and treat obesity.
Introduction:
Tea is the second most commonly consumed beverage in the world after water. The leaf and bud of the plant Camellia sinensis produces tea. The different forms of tea are 'non-fermented' green tea, 'semi-fermented' oolong tea and 'fermented' black tea according to the manufacturing process. Streptococcus mutans is the main causative organism in dental caries and plaque formation.
Aim:
The present study was undertaken to determine the antibacterial effectiveness of aqueous and ethanol extracts of green tea, black tea and oolong tea against S. mutans in comparison with 0.2% chlorhexidine.
Materials and methods:
An in vitro study was conducted to compare the effectiveness of aqueous and ethanol extracts of green tea, black tea and oolong tea with 0.2% chlorhexidine against S. mutans. Chlorhexidine 0.2% commercially available as mouthwash was used as such for comparison. The antimicrobial activity was determined using agar well diffusion method. About 50 µl of the aqueous and ethanol extracts of tea and 0.2% chlorhexidine were inoculated into the wells prepared on blood agar plates smeared with S. mutans. The agar plates were incubated for 24 hours after which the diameter of the zone of inhibition was measured. Analysis of Variance (ANOVA) followed by Tukey's post hoc test were used for statistical analysis.
Results:
The mean zone of inhibition of the aqueous extracts of green tea, black tea, oolong tea and chlorhexidine was found to be 16.33 mm, 10.33 mm, 19.66 mm and 22 mm respectively. The mean zone of inhibition of the ethanol extracts of green tea, black tea, oolong tea and chlorhexidine was found to be 14 mm, 9 mm, 20.66 mm and 22 mm respectively. The study result state that the inhibitory effect of chlorhexidine is almost similar to that of oolong tea followed by green tea and black tea.
Conclusion:
From the present study, it can be concluded that the aqueous and ethanol extracts of oolong tea showed highest antimicrobial activity compared to green tea and black tea.
Tea, one of the most widely consumed beverages in the world, is produced from the leaves of the plant Camellia sinensis L.. Tea has important physiological properties and potential health benefits due to the presence of compounds such as polyphenols, amino acids, vitamins, carbohydrates, caffeine, and purine alkaloids. Tea is produced in three types as green tea (unfermented), oolong tea (partially fermented), and black tea (fully fermented). Black tea is consumed worldwide, whereas green and oolong teas are consumed mainly in Asia and North Africa. The total tea production in the world consists of about 78% black tea, 20% green tea and
IntroductionEnergy expenditure: definition, measurement and componentsDefinitionsMeasurementsComponents of energy expenditureResting energy expenditurePhysical activityMechanisms and sites of thermogenesis and the sympathetic nervous systemThermogenic stimuliThe sympathetic nervous systemObesity and energy expenditure
Dementia and diabetes mellitus are prevalent disorders in the elderly population. While recognized as two distinct diseases, diabetes has more recently recognized as a significant contributor to risk for developing dementia, and some studies make reference to type 3 diabetes, a condition resulting from insulin resistance in the brain. Alzheimer's disease, the most common form of dementia, and diabetes, interestingly, share underlying pathological processes, commonality in risk factors, and, importantly, pathways for intervention. Tea has been suggested to possess potent antioxidant properties rich in phytochemicals including, flavonoids, tannins, caffeine, polyphenols, boheic acid, theophylline, theobromine, anthocyanins, gallic acid, and finally epigallocatechin-3-gallate, considered the most potent active ingredient. Flavonoid phytochemicals, known as catechins, within tea offer potential benefits for reducing the risk of diabetes and Alzheimer's disease by targeting common risk factors, including obesity, hyperlipidemia, hypertension, cardiovascular disease, and stroke. Studies also show that catechins may prevent the formation of amyloid-β plaques and enhance cognitive functions, and thus may be useful in treating patients who have Alzheimer's disease or dementia. Furthermore, other phytochemicals found within tea offer important antioxidant properties along with innate properties capable of modulating intracellular neuronal signal transduction pathways and mitochondrial function.
Scope:
Consumption of products rich in flavan-3-ols, such as tea and cocoa, has been associated with decreased obesity, partially dependent on their capacity to enhance energy expenditure. Despite these phenolics having been reported to increase the thermogenic program in brown and white adipose tissue, flavan-3-ols are vastly metabolised in vivo to phenyl-γ-valerolactones. Therefore, we hypothesize that phenyl-γ-valerolactones may directly stimulate the differentiation and the activation of brown adipocytes.
Methods and results:
Immortalized brown pre-adipocytes were differentiated in presence of (R)-5-(3',4'-dihydroxyphenyl)-γ-valerolactone (VL1), (R)-5-(3'-hydroxyphenyl)-γ-valerolactone-4'-O-sulphate (VL2), (R)-5-phenyl-γ-valerolactone-3',4'-di-O-sulphate (VL3), at concentrations of 2 or 10μM, whereas fully differentiated brown adipocyte were treated acutely (6-24h). None of the treatments regulated the expression levels of the uncouple protein 1, nor of the main transcription factors involved in brown adipogenesis. Similarly, mitochondrial content was unchanged after treatments. Moreover these compounds did not display peroxisome proliferator-activated receptor γ-agonist activity, as evaluated by luciferase assay, and did not enhance norepinephrine-stimulated lipolysis in mature adipocytes. However, both VL1 and VL2 prevented oxidative stress caused by H2 O2 .
Conclusion:
Phenyl-γ-valerolactones and their sulphated forms do not influence brown adipocyte development or function at physiological or supraphysiological doses in vitro, but they are active protecting brown adipocytes from increased reactive oxygen species production. This article is protected by copyright. All rights reserved.
Green tea catechins (GTCs) are known to improve fat oxidation 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 randomized controlled trials (RCTs) on EGCG, we carried out a systematic review and meta-analysis to elucidate whether EGCG consumption indeed increase energy expenditure and promote fat oxidation. A systematic review of the literature was conducted using electronic databases (PubMed, Embase, Cochrane Library, CINAHL, JICST, JSTPLUS, and JMEDPLUS and others) and 8 RCTs were included. RCTs were reviewed using preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines and methodological quality was assessed. After data extraction, results were aggregated using fixed and random effect approaches and expressed to quantify the relationship between the dose of EGCG for respiratory quotient (RQ), energy expenditure (EE), and rate of fat oxidation (FOX) to compare the EGCG and placebo treatments. The meta-analysis results of verities of studies in term of dose and length of duration revealed that EGCG supplementation provided significant mean difference (MD) when compared with placebo for RQ [MD: -0.02; 95%CI, −0.04 to 0.00; I²=67%; P=.01] and EE [MD: 158.05 kJ/day; 95%CI, 4.72 to 311.38; I²=0%; P=.04] in fixed-effect approach. Changes in FOX did not reach the level of statistical significance. Meta-analyses of EGCG influence on the body mass index (BMI), waist circumference (WC), and total body fat mass (TBFM) were also examined and their impact on the promotion of fat oxidation is reported. Effect of EGCG doses was also systematically reviewed. Finding showed that EGCG intake moderately accelerates energy expenditure, and reduces respiratory quotient. The analyses revealed that the EGCG resulted in difference in respiratory quotient and energy expenditure 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 support the findings that EGCG has an effect on metabolic parameters. However, the large prospective trials are needed to confirm the findings.
Single-dose oral administration of 100 mg caffeine increased the resting metabolic rate of both lean and postobese human volunteers by 3-4% (p less than 0.02) over 150 min and improved the defective diet-induced thermogenesis observed in the postobese subjects. Measurements of energy expenditure (EE) in a room respirometer indicate that repeated caffeine administration (100 mg) at 2-h intervals over a 12-h day period increased the EE of both subject groups by 8-11% (p less than 0.01) during that period but had no influence on the subsequent 12-h night EE. The net effect was a significant increase (p less than 0.02) in daily EE of 150 kcal in the lean volunteers and 79 kcal in the postobese subjects. Caffeine at commonly consumed doses can have a significant influence on energy balance and may promote thermogenesis in the treatment of obesity.
Sources of error in the interpretation of respiratory data are evaluated and reviewed with special reference to the detailed composition of foods. Estimates of fuel utilization or synthesis are 12-fold more sensitive to errors in the nonprotein respiratory quotient than is the heat equivalent of oxygen. Estimates of protein oxidation from nitrogen excretion can be in error from +14 to -39% of the true value. Heat equivalents of oxygen, respiratory quotients, and urinary nitrogen-to-oxygen conversion ratios are considered for 60 artificial and 101 conventional food proteins, 36 artificial and 125 conventional food fats, and the different carbohydrates contained in these foods. It is concluded that there is considerable uncertainty when the mix of fuels utilized is assessed accurately. Accuracy is best within 5% of the true values. This analysis is completed with descriptions of some physiological sources of error in an appendix.
A simple inexpensive indirect calorimeter that is suitable for the estimation of energy expenditure in man is described. Its usefulness is demonstrated by a study of the effect of coffee on energy expenditure. Caffeinated coffee increased energy expenditure by 16% over 1 2-h period compared with decaffeinated coffee.
The magnitude of coffee-induced thermogenesis and the influence of coffee ingestion on substrate oxidation were investigated in 10 lean and 10 obese women, over two 24-h periods in a respiratory chamber. On one occasion the subjects consumed caffeinated coffee and on the other occasion, decaffeinated coffee. The magnitude of thermogenesis was smaller in obese (4.9 +/- 2.0%) than in lean subjects (7.6 +/- 1.3%). The thermogeneic response to caffeine was prolonged during the night in lean women only. The coffee-induced stimulation of energy expenditure was mediated by a concomitant increase in lipid and carbohydrate oxidation. During the next day, in postabsorptive basal conditions, the thermogenic effect of coffee had vanished, but a significant increase in lipid oxidation was observed in both groups. The magnitude of this effect was, however, blunted in obese women (lipid oxidation increased by 29 and 10% in lean and obese women, respectively). Caffeine increased urinary epinephrine excretion. Whereas urinary caffeine excretion was similar in both groups, obese women excreted more theobromine, theophylline, and paraxanthine than lean women. Despite the high levels of urinary methylxanthine excretion, thermogenesis and lipid oxidation were less stimulated in obese than in lean subjects.
The inhibitory activity of tea against tumorigenesis has been demonstrated in many animal models and has been suggested by some epidemiological studies. Such activity has generally been attributed to tea catechins. To understand the bioavailability of tea catechins in humans, we gave 18 individuals different amounts of green tea and measured the time-dependent plasma concentrations and urinary excretion of tea catechins. After taking 1.5, 3.0, and 4.5 g of decaffeinated green tea solids (dissolved in 500 ml of water), the maximum plasma concentration (Cmax) of (-)-epigallocatechin-3-gallate (EGCG) was 326 ng/ml, the Cmax of (-)-epigallocatechin (EGC) was 550 ng/ml, and the Cmax of (-)-epicatechin (EC) was 190 ng/ml. These Cmax values were observed at 1.4-2.4 h after ingestion of the tea preparation. When the dosage was increased from 1.5 to 3.0 g, the Cmax values increased 2.7-3.4-fold, but increasing the dose to 4.5 g did not increase the Cmax values significantly, which suggested a saturation phenomenon. The half-life of EGCG (5.0-5.5 h) seemed to be higher than the half-life of EGC or EC (2.5-3.4 h). EGC and EC, but not EGCG, were excreted in the urine. Over 90% of the total urinary EGC and EC was excreted within 8 h. When the tea dosage was increased, the amount of EGC and EC excretion seemed to increase, but a clear dose-response relationship was not observed. The present study provides basic pharmacokinetic parameters of green tea catechins in humans; these parameters may be used to estimate the levels of these compounds after drinking tea.
The purpose of this study was to examine age-related differences in the magnitude of caffeine-induced thermogenesis and the relationship of aerobic fitness, body composition, and hormone and substrate concentrations to the thermic effect of caffeine in younger and older women. Using a placebo-controlled, double-blind study design, 10 older (50 to 67 years) and 10 younger (21 to 31 years) healthy women who were moderate consumers of caffeine (self-reported intake: younger, 139 +/- 152 mg/d; older, 204 +/- 101 mg/d, NS, mean +/- SD) were characterized for fasting plasma glucose, insulin, free fatty acid (FFA), and caffeine levels, energy expenditure, body composition, anthropometry, aerobic fitness, physical activity, and energy intake. Before and after placebo and caffeine ingestion (5 mg/kg fat-free mass [FFM]), the following variables were measured: fasting plasma glucose, insulin, FFA, and energy expenditure, plasma glucose, insulin, and FFA, and energy expenditure in response to placebo and caffeine ingestion. Caffeine ingestion resulted in similar increases in younger and older women for plasma caffeine (younger, 80 +/- 34 to 5,604 +/- 528 ng/mL, P < .01; older, 154 +/- 134 to 5,971 +/- 867 ng/mL, P < .01) and fatty acids (younger, 294 +/- 118 to 798 +/- 248 micromol/L, P < .01; older, 360 +/- 180 to 727 +/- 310 micromol/L, P < .01), whereas plasma insulin and glucose levels remained unchanged from baseline. Energy expenditure increased following caffeine ingestion in both groups (younger, 15.4%, 1.09 +/- 0.14 to 1.24 +/- 0.13 kcal/min, P < .05; older, 7.8%, 0.98 +/- 0.14 to 1.06 +/- 0.12 kcal/min, P < .05), although there was a blunted thermic response in the older versus younger women (older, 6.9 +/- 5 kcal/90 min; younger, 15.5 +/- 7 kcal/90 min, P < .05). In younger women, the thermic response to caffeine was positively correlated with the waist circumference (r = .70, P < .05) and body weight (r = .91; P < .01), whereas aerobic fitness (r = .77; P < .05) was the only significant correlate in older women. In conclusion, older and younger women increase energy expenditure significantly following caffeine ingestion, but older women have a blunted thermic response compared with younger women. Second, the thermic response to caffeine is positively associated with the body weight and waist circumference in younger women, whereas a positive association with aerobic fitness was observed in older women. Thus, the physiologic determinants of the thermic response to caffeine differ among women of different age groups.
A simple and fast high performance liquid chromatographic
method for five catechins and caffeine using an ODS column and a
water–acetonitrile–formic acid mobile phase system was
developed. The catechins (epicatechin, catechin, epigallocatechin,
epigallocatechin gallate, epicatechin gallate) and caffeine were separated
by an acetonitrile gradient within 20 min. The detection limit of the
method was approximately 10 ng for all the compounds (by injecting 10
μL). Several green, black and instant teas were analysed using this
method. By using the studied compounds as chemical descriptors, linear
discriminant analysis was performed and complete differentiation of the
green, black and instant teas was achieved.
Tea consumption has been associated with reduced risk of both cancer and cardiovascular disease in population studies, but clinical data demonstrating bioavailability of the individual catechins and other polyphenolic components of tea are limited. This study assessed the apparent bioavailability of the prominent catechins from black tea in humans drinking tea throughout the day. After 5 d of consuming a low flavonoid diet, subjects drank a black tea preparation containing 15.48, 36.54, 16.74, and 31.14 mg of (-)-epigallocatechin (EGC), (-)-epicatechin (EC), (-)-epigallocatechin gallate (EGCG) and (-)-epicatechin gallate (ECG), respectively, at four time points (0, 2, 4 and 6 h). Blood, urine and fecal specimens were collected over a 24- to 72-h period and catechins were quantified by HPLC with coularray detection. Plasma concentrations of EGC, EC and EGCG increased significantly relative to baseline (P < 0.05). Plasma EGC, EC and EGCG peaked after 5 h, whereas ECG peaked at 24 h. Urinary excretion of EGC and EC, which peaked at 5 h, was increased relative to baseline amounts (P < 0.05) and fecal excretion of all four catechins was increased relative to baseline (P < 0.05). Approximately 1.68% of ingested catechins were present in the plasma, urine and feces, and the apparent bioavailability of the gallated catechins was lower than the nongallated forms. Thus, catechins were bioavailable. However, unless they are rapidly metabolized or sequestered, the catechins appeared to be absorbed in amounts that were small relative to intake.
Tea is the most popular beverage, consumed by over two thirds of the world's population. Tea is processed differently in different parts of the world to give green (20%), black (78%) or oolong tea (2%). Green tea is consumed mostly in Japan and China. The antimutagenic and anticarcinogenic activities of green tea are extensively examined. The chemical components of green and black tea are polyphenols, which include EC, ECG, EGC, EGCG and TFs. This article reviews the epidemiological and experimental studies on the antimutagenicity and anticarcinogenicity of tea extracts and tea polyphenols. In Japan, an epidemiological study showed an inverse relationship between habitual green tea drinking and the standardized mortality rates for cancer. Some cohort studies on Chanoyu (Japanese tea ceremony) women teachers also showed that their mortality ratio including deaths caused by malignant neoplasms were surprisingly low. The antimutagenic activity against various mutagens of tea extracts and polyphenols including ECG and EGCG has been demonstrated in microbial systems (Salmonella typhimurium and Escherichia coli), mammalian cell systems and in vivo animal tests. The anticarcinogenic activity of tea phenols has been shown in experimental animals such as rats and mice, in transplantable tumors, carcinogen-induced tumors in digestive organs, mammary glands, hepatocarcinomas, lung cancers, skin tumors, leukemia, tumor promotion and metastasis. The mechanisms of antimutagenesis and anticarcinogenesis of tea polyphenols suggest that the inhibition of tumors may be due to both extracellular and intracellular mechanisms including the modulation of metabolism, blocking or suppression, modulation of DNA replication and repair effects, promotion, inhibition of invasion and metastasis, and induction of novel mechanisms.
A calorimeter suitable for measuring human energy expenditure has been assembled by the US Department of Agriculture in Beltsville, Maryland. The room-sized calorimeter is 3.05 X 2.74 X 2.44 m (20.39 m3). Direct and indirect calorimetry methods are used to simultaneously measure heat emission and energy expenditure. A water-cooled gradient layer chamber is used to measure human heat production directly. Indirect calorimetry is ascertained by measuring the changes in gas composition of the air entering and existing the chamber. The inlet and outlet air are each sampled three times every 100 s with a multiple gas analyzer to determine carbon dioxide and methane production and oxygen consumption within the chamber. A total of 30 measurements, which include temperature, pressure, gas fractions, flow rates, direct heat transfer, electrical power, and motion within the chamber, are converted from electrical to digital signals and recorded on magnetic disk nine times each minute. Real-time calculations for directly and indirectly measured energy expenditure are continuously updated and displayed. The performance of the calorimeter is assessed by the combustion of alcohol within the chamber. Results of these tests indicate that the direct heat recovery is 99.7 +/- 2.6 (SD) % and the indirect heat recovery is 100.3 +/- 1.3 (SD) %.
To estimate sources and extent of variation in energy expenditure (EE), as measured by indirect calorimetry in a room-sized human calorimeter, a number of 24-h measurements were compiled. Measured oxygen consumption and carbon dioxide production from alcohol combustion experiments averaged 101.5% of the theoretical value with a coefficient of variation (CV) of 1.4%. Experiment 1 consisted of four men who had the following averages: age, 41 y; height, 179 cm; weight, 84.6 kg; and fat, 23.5%. Five measurements, separated by 1 d, were made on each subject. Daily and basal EE averaged 2852 and 1691 kcal/d, respectively, with a within-subject CV of 2.7% and 2.4%, respectively. Experiment 2 consisted of five men who had the following averages: age, 48 y; height, 181.6 cm; weight, 87 kg; and fat, 23%. Five measurements made on each subject were separated by 1-3 wk. Daily and basal EE averaged 2619 and 1837 kcal/d, respectively, with a within-subject CV of 4.6% and 2.9%, respectively.
In humans caffeine stimulates thermogenesis by unknown mechanisms and its effect on body weight has not been studies. The effect of placebo and 100, 200, and 400 mg oral caffeine on energy expenditure, plasma concentrations of substrates and hormones, blood pressure, and heart rate was investigated in a double-blind study in healthy subjects who had a moderate habitual caffeine consumption. Caffeine increased energy expenditure dose dependently and the thermogenic response was positively correlated with the response in plasma caffeine (r = 0.52; p less than 0.018), plasma lactate (r = 0.79; p less than 0.000001), and plasma triglyceride (r = 0.53; p less than 0.02). Stepwise regression analysis with the thermogenic response as the dependent variable excluded plasma caffeine and yielded the following equation: thermic effect (kcal/3 h) = -0.00459 X heart rate + 0.30315 X (triglyceride) + 0.53114 X (lactate) + 15.34 (r = 0.86; p = 0.0001). The results suggest that lactate and triglyceride production and increased vascular smooth muscle tone may be responsible for the major part of the thermogenic effect of caffeine.
A series of four trials was carried out to investigate the effects of caffeine and coffee on the metabolic rate and substrate utilization in normal weight and obese individuals. In the first trial 8 mg/kg caffeine was compared with a placebo in normal weight subjects. Metabolic rate increased significantly during the 3 hr after caffeine ingestion. While plasma glucose, insulin, and carbohydrate oxidation did not change significantly, plasma free fatty acid levels rose from 432 +/- 31 to 848 +/- 135 muEq/liter and were accompanied by significant increases in fat oxidation during the last hour of the test. In the second and third trials the effects of coffee providing 4 mg/kg caffeine were studied in control and obese subjects. Metabolic rate increased significantly in both groups; however, significant increases in fat oxidation were only observed in the control group. Plasma free fatty acids did not change in the obese. In the fourth trial, coffee was taken with a 3080 kJ meal. The thermic effect of the meal was significantly greater after coffee than after decaffeinated coffee and again fat oxidation was significantly greater after coffee. In conclusion caffeine/coffee stimulates the metabolic rate in both control and obese individuals; however, this is accompanied by greater oxidation of fat in normal weight subjects.
A high performance liquid chromatographic procedure for the stimultaneous micro-scale determination of theophylline, theobromine and caffeine in plasma is described. After a single dichloromethane extraction of 0.5--0.2 ml of acidified plasma, the evaporated residue is chromatographed on a reverse-phase gC-18) column. With a mobile phase of acetate buffer (pH 4)--acetonitrile (88:12) at a flow-rate of 2.0 ml/min., the three methylxanthines are separated within six minutes. Detection at xanthines are separated within six minutes. Detection at 276-280 nm enables quantitation of 0.1 mg/1 of drug in a 0.1 ml sample. The method is reproducible, correlates well with EMIT for plasma theophylline, and is applicable to the routine monitoring of both paediatric and adult patients as well as to metabolic studies.
Green, oolong and black teas were extracted with water, and then the water extracts were extracted separately with three types of solvent, chloroform, ethyl acetate and butanol, to obtain eight fractions. Major flavanol was extracted by EtOAc, while most of the alkaloid was in the chloroform fraction. Thearubigin was greatest in the butanol fraction, and most of the amino acid remained in the water fraction. All fractions were systematically analyzed by UV spectrophotometer and reverse phase HPLC for those important components existing in green tea, oolong tea, and black tea. The pure compounds of (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC), (-)-epigallocatechin gallate (EGCG), free theaflavin, theaflavin monogallate-A, theaflavin monogallate-B, and theaflavin digallate were separated by LH-20 chromatography and reverse phase HPLC. All fractions and pure compounds were assayed for antioxidant activity and lipoxygenase inhibition activity. Flavanol showed very strong antioxidant activity and lipoxygenase inhibition.
To determine whether or not aspirin further potentiates the greater post-prandial thermogenesis induced by ephedrine with caffeine.
Determination of the acute metabolic rate response to the following treatments: 1050 kJ liquid meal (M); meal plus ephedrine (30 mg) and caffeine (100 mg) (MEC) or meal plus ephedrine, caffeine and aspirin (300 mg) (MECA).
Lean, pre-disposed obese and obese women (n = 10 each group).
Pre- and post-treatment metabolic rate determinations via indirect calorimetry. Post-treatment measurements made at 20 min intervals for a total of 160 min.
In all groups, metabolic rate increased significantly more following the MEC or MECA, compared to the meal only (p < 0.05). The obese group had a significantly greater absolute increase in metabolic rate following the MECA and MEC compared to both the lean and pre-disposed obese groups (p < 0.05). Metabolic rate remained elevated at the end of the 160 min following all treatments.
Aspirin does not further potentiate the acute thermic effect of ephedrine and caffeine with a meal. However, the full thermogenic response was not measured and longer duration studies are necessary to confirm these results.
Chinese teas with different degrees of fermentation were examined for their effect on diet-induced hypercholesterolemia in rats. The teas tested were Chinese Green tea, Jasmine, Iron Buddha, Oolong and Pu erh. Hypercholesterolemia was induced by feeding rats with a cholesterol-enriched diet for 1 week. They were then treated with different tea extracts together with a cholesterol-enriched diet for another 8 weeks. Chinese Green tea and Jasmine tea, both with a minimum degree of fermentation, were found to have significant serum and liver cholesterol lowering effects. They also reduced the increase in liver weight due to lipid deposition. All tea treatments lowered the atherogenic index and increased the HDL-total cholesterol ratio, while HDL-cholesterol and triglyceride levels were not significantly affected. Analysis of catechin levels in tea extracts showed that the individual catechin component in Chinese Green tea and Jasmine tea were significantly higher than the others. (-)-Epicatechin gallate and (-)-epigallocatechin gallate in the tea extracts may account for their hypocholesterolemic effect.
Oolong tea is traditionally reported to have anti-obesity and hypolipidaemic effects. The present study was performed to clarify whether oolong tea prevented obesity induced in mice by the oral administration of a high-fat diet for 10 weeks.
High-fat diet-induced obese mice were treated with oolong tea for 10 weeks. The effects of various active fractions isolated from oolong tea on noradrenaline-induced lipolysis were examined with isolated fat cells and a cell-free system consisting of lipid droplets and hormone-sensitive lipase (HSL).
The mean food consumption was not significantly different between high-fat diet-treated mice and high-fat plus oolong tea diet-treated mice. Oolong tea prevented the obesity and fatty liver induced by a high-fat diet. A water extract of oolong tea enhanced noradrenaline-induced lipolysis, and the active substance was identified as caffeine. Caffeine enhanced noradrenaline-induced lipolysis in fat cells without a concomitant increase in HSL activity and also accelerated the hormone-induced lipolysis in a cell-free system consisting of lipid droplets and HSL, but not in the cell-free system with sonicated lipid droplets and HSL. Oolong tea extract inhibited pancreatic lipase activity.
It was demonstrated that the anti-obesity effects of oolong tea in high-fat diet-treated mice might be due partly to the enhancing effect of caffeine isolated from oolong tea on noradrenaline-induced lipolysis in adipose tissue, and to the inhibitory action of some other substance in oolong tea on pancreatic lipase activity. Caffeine was found to enhance lipolysis through acting on lipid droplets but not on HSL. The results suggest that oolong tea may be an effective crude drug for the treatment of obesity and fatty liver caused by a high-fat diet.
This study aimed to compare in vitro antioxidant power of different types of tea (Camellia sinensis). The ferric reducing/antioxidant power (FRAP) assay was used to measure the total antioxidant power of freshly prepared infusions of 25 types of teas. Results showed that different teas had widely different in vitro antioxidant power and that the antioxidant capacity was strongly correlated (r = 0. 956) with the total phenolics content of the tea. Expressed as micromol of antioxidant power/g of dried tea leaves, values ranged as 132-654 micromol/g for black ("fermented") teas, 233-532 micromol/g for Oolong ("semifermented") teas, and 272-1144 micromol/g for green ("nonfermented") teas. One cup of tea of usual strength (1-2%), therefore, can provide the same potential for improving antioxidant status as around 150 mg of pure ascorbic acid (vitamin C).
Current interest in the role of functional foods in weight control has focused on plant ingredients capable of interfering with the sympathoadrenal system.
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.
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 randomly 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.
Relative to placebo, treatment with the green tea extract resulted 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.
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.
Green tea polyphenols, especially the catechin, (-)-epigallocatechin gallate (EGCG), have been proposed as a cancer chemopreventative based on a variety of laboratory studies. For clear assessment of the possible physiological effects of green tea consumption, we injected pure green tea catechins ip into rats and studied their acute effects on endocrine systems. We found that EGCG, but not related catechins, significantly reduced food intake; body weight; blood levels of testosterone, estradiol, leptin, insulin, insulin-like growth factor I, LH, glucose, cholesterol, and triglyceride; as well as growth of the prostate, uterus, and ovary. Similar effects were observed in lean and obese male Zucker rats, suggesting that the effect of EGCG was independent of an intact leptin receptor. EGCG may interact specifically with a component of a leptin-independent appetite control pathway. Endocrine changes induced by parenteral administration of EGCG may relate to the observed growth inhibition and regression of human prostate and breast tumors in athymic mice treated with EGCG as well as play a role in the mechanism by which EGCG inhibits cancer initiation and promotion in various animal models of cancer.
The thermogenic effect of tea is generally attributed to its caffeine content. We report here that a green tea extract stimulates brown adipose tissue thermogenesis to an extent which is much greater than can be attributed to its caffeine content per se, and that its thermogenic properties could reside primarily in an interaction between its high content in catechin-polyphenols and caffeine with sympathetically released noradrenaline (NA). Since catechin-polyphenols are known to be capable of inhibiting catechol-O-methyl-transferase (the enzyme that degrades NA), and caffeine to inhibit trancellular phosphodiesterases (enzymes that break down NA-induced cAMP), it is proposed that the green tea extract, via its catechin-polyphenols and caffeine, is effective in stimulating thermogenesis by relieving inhibition at different control points along the NA-cAMP axis. Such a synergistic interaction between catechin-polyphenols and caffeine to augment and prolong sympathetic stimulation of thermogenesis could be of value in assisting the management of obesity. International Journal of Obesity (2000) 24, 252-258
The absorption characteristics and oral bioavailability of three tea catechins, namely (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), and (-)-epigallocatechin gallate (EGCG), were assessed in this study. Male Sprague Dawley rats (210-230 g) received either an intravenous (i.v. 50 mg/kg) or oral (5000 mg/kg) dose of decaffeinated catechin-fraction containing EC (5%), EGCG (50%), and ECG (13%). Concentrations of the compounds in plasma, urine, and feces were measured using HPLC. A non-compartmental approach was employed for pharmacokinetic analysis. Results indicated that maximum plasma concentrations for the catechins (15-112 micrograms/ml) were achieved at 2 h post-oral dosing and the apparent volume of distribution (Vd/F) ranged from 30 to 63 l/kg. Absolute bioavailability (F) of EC, EGCG, and ECG was assessed to be 0.39, 0.14, and 0.06, respectively. Estimates of terminal elimination half-life (t1/2, lambda z) of the catechins after oral dosing were 451-479 min and were 1.4-10 fold longer than those observed for the i.v. dosing. The discrepancy in terminal elimination and low rate and extent of absorption indicated the possibility of flip-flop kinetics. Respective urinary recoveries were 0.17-4.72% and 2.11-14.2% after oral and i.v. dosing. In conclusion, the low systemic availability of tea catechins observed could be a result of slow absorption, high first pass effect, and wide tissue distribution.
Beneficial health effects of tea have been demonstrated in animal experiments and some human studies. The two most extensively investigated diseases are cancer and heart disease. Although mechanisms of protective activity of tea against these diseases have been proposed, there are inconsistencies in the relationship between tea consumption and the risk of these diseases in humans. The bioavailability of active components is beginning to be understood, but further research is required to determine whether the results from animal studies are applicable to humans. Also discussed are the possible effects of tea in increasing thermogenesis and bone density as well as decreasing risk of cataracts and arthritis. The potential health benefits of tea consumption warrant further investigation.
Clinical efficacy of oolong tea in simple obesity
- W Y Chen
- Z-B Yang
- K Hosoda
- L Chen
- B H Lin
- J Kimura
- Y Matsui
- K Matsui
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