Effects of dietary supplementation with epigallocatechin-3-gallate on weight loss, energy homeostasis, cardiometabolic risk factors and liver function in obese women: randomised, double-blind, placebo-controlled clinical trial

Effects of green tea consumption on glycemic control: a systematic review and meta-analysis of randomized controlled trials

Background

The results of human clinical trials investigating the effects of green tea on glycemic control are inconsistent.

Methods

We conducted a systematic review and meta-analysis of RCTs that examined the effects of green tea supplementation on glycemic control. A literature search in PubMed, Embase, and Cochrane Library databases for RCTs that investigated the effect of green tea consumption on glycemic control was performed up to February 2020. A random-effects model was used to estimate weighted mean difference (WMD) with 95% confidence intervals (CIs).

Results

Twenty-seven trials involving 2194 subjects were included in the meta-analysis. The pooled results showed that green tea significantly lowered fasting blood glucose by − 1.44 mg/dL (95%CI:-2.26, − 0.62 mg/dL; P < 0.001) with no obvious heterogeneity (I² = 7.7%). However, green tea consumption did not significantly affect fasting insulin and HbA1c values. The mean differences were − 0.46μIU/mL (95% CI: − 1.10, 0.17μIU/mL; P = 0.21) for fasting insulin and − 0.06%; (95% CI: − 0.12, 0.01%; P = 0.07) for HbA_1c concentrations. Heterogeneity was significant in fasting insulin (I² = 46.8%) and mild in HbA_1c (I² = 1.7%).

Conclusions

In short-term trials, green tea supplementation significantly reduced fasting glucose, but had no significant effect on fasting insulin and HbA_1c. Long-term trials assessing the effects of green tea supplementation on glycemic control are needed.

The Effects of Polyphenol Supplementation in Addition to Calorie Restricted Diets and/or Physical Activity on Body Composition Parameters: A Systematic Review of Randomized Trials

Background: Both, calorie restricted diets (CRD) and physical activity (PA) are conventional obesity therapies but their effectiveness is usually limited in the long-term. Polyphenols are bioactive compounds that have shown to possess some anti-obesity properties. The synergic effects between dietary polyphenols and CRD or PA on body weight and fat are supported by several animal studies, but evidence in human is still inconsistent. Thus, our aim was to review the combined effects of polyphenol supplementation with CRD and/or PA on body weight and fat, body mass index (BMI) and waist circumference (WC) in overweight or obese adults. Methods: Electronic databases (PubMed, Web of Science and Cochrane CENTRAL) were searched for randomized clinical trials (RCT) examining the combination of polyphenols with CRD and/or PA (up to December 31st, 2019). Articles were included if they had a duration of intervention ≥ 4 weeks. Both, quality and risk of bias of the included studies were assessed using the Cochrane RoB2 Tool. Results: The review included 4 and 11 RCTs investigating the anti-obesity effects of polyphenol supplementation combined with CRD and PA, respectively. Isoflavone supplementation may increase fat loss during exercise among post-menopausal women in non-Asian studies. In the rest of RCTs regarding polyphenol supplementation and CRD or PA, no additive changes were found. Conclusion: The results do not yet support polyphenol supplementation as a complementary strategy for enhancing the effectiveness of CRD and PA on weight and fat loss. However, this review suggests that isoflavone and soy products combined with lifestyle changes, especially exercise, provide additional anti-obesity effects in postmenopausal women. The potential role of polyphenols alone or, especially, in addition to conventional therapies (CRD and PA) mostly remains uncertain; and therefore, larger and longer RCTs examining these effects are needed. Protocol Registration: PROSPERO CRD42020159890.

Effectiveness of herbal medicines for weight loss: A systematic review and meta-analysis of randomized controlled trials

AIM

To update the available evidence on the efficacy and safety of complementary medicines to assist in weight loss by conducting a systematic review and meta-analysis of herbal medicines for weight loss.

METHODS

Four electronic databases (Medline, Embase, CINAHL and Web of Science) were searched from inception until August 2018. A total of 54 randomized placebo-controlled trials of healthy overweight or obese adults were identified. Meta-analyses were conducted for herbal medicines with ≥4 studies available. Weight differences of ≥2.5 kg were considered clinically significant.

RESULTS

As a single agent, only Phaseolus vulgaris resulted in a statistically significant weight loss compared to placebo, although this was not considered clinically significant. No effect was seen for Camellia sinensis or Garcinia cambogia. Statistically, but not clinically, significant differences were observed for combination preparations containing C. sinensis, P. vulgaris or Ephedra sinica. Of the herbal medicines trialled in ≤3 randomized controlled trials, statistically and clinically significant weight loss compared to placebo was reported for Irvingia gabonensis, Cissus quadrangularis, and Sphaeranthus indicus combined with Garcinia mangostana, among others, but these findings should be interpreted cautiously because of the small number of studies, generally poor methodological quality, and poor reporting of the herbal medicine interventions. Most herbal medicines appeared safe for consumption over the short duration of the studies (commonly ≤12 weeks). Some warrant further investigation to determine effect size, dosage and long-term safety.

CONCLUSION

There is currently insufficient evidence to recommend any of the herbal medicines for weight loss included in the present review.

Effect of green tea consumption on blood lipids: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Strong epidemiologic evidence indicates that green tea intake is protective against hyperlipidemia; however, randomized controlled studies have presented varying results. In the present study, we aimed to conduct a literature review and meta-analysis to assess the effect of green tea on blood lipids.

METHODS

PubMed, Embase, and the Cochrane Library were electronically explored from inception to September 2019 for all relevant studies. Random effect models were used to estimate blood lipid changes between green tea supplementation and control groups by evaluating the weighted mean differences (WMD) with 95% confidence intervals (CIs). The risk of bias for study was assessed using the Cochrane tool. Publication bias was evaluated using funnel plots and Egger's tests.

RESULTS

Thirty-one trials with a total of 3321 subjects were included in the meta-analysis. In general, green tea intake significantly lowered the total cholesterol (TC); WMD: - 4.66 mg/dL; 95% CI: - 6.36, - 2.96 mg/dL; P < 0.0001) and low-density lipoprotein (LDL) cholesterol (WMD:- 4.55 mg/dL; 95% CI: - 6.31, - 2.80 mg/dL; P < 0.0001) levels compared with those in the control. Green tea consumption did not affect high-density lipoprotein (HDL) cholesterol; however, it reduced the triglycerides compared with that in the control (WMD: - 3.77 mg/dL; 95% CI: - 8.90, 1.37 mg/dL; P = 0.15). In addition, significant publication bias from funnel plots or Egger's tests was not evident.

CONCLUSIONS

Collectively, consumption of green tea lowers LDL cholesterol and TC, but not HDL cholesterol or triglycerides in both normal weight subjects and those who were overweight/obese; however, additional well-designed studies that include more diverse populations and longer duration are warranted.

The Pharmacological Activity of Camellia sinensis (‎L.‎) ‎Kuntze‎ on Metabolic and Endocrine Disorders: A Systematic Review

Tea made from Camellia sinensis leaves is one of the most consumed beverages worldwide. This systematic review aims to update Camellia sinensis pharmacological activity on metabolic and endocrine disorders. Inclusion criteria were preclinical and clinical studies of tea extracts and isolated compounds on osteoporosis, hypertension, diabetes, metabolic syndrome, hypercholesterolemia, and obesity written in English between 2014 and 2019 and published in Pubmed, Science Direct, and Scopus. From a total of 1384 studies, 80 reports met inclusion criteria. Most papers were published in 2015 (29.3%) and 2017 (20.6%), conducted in China (28.75%), US (12.5%), and South Korea (10%) and carried out with extracts (67.5%, especially green tea) and isolated compounds (41.25%, especially epigallocatechin gallate). Most pharmacological studies were in vitro and in vivo studies focused on diabetes and obesity. Clinical trials, although they have demonstrated promising results, are very limited. Future research should be aimed at providing more clinical evidence on less studied pathologies such as osteoporosis, hypertension, and metabolic syndrome. Given the close relationship among all endocrine disorders, it would be of interest to find a standard dose of tea or their bioactive constituents that would be beneficial for all of them.

Modulation of Glucose Metabolism by Leaf Tea Constituents: A Systematic Review of Recent Clinical and Pre-clinical Findings

Leaf teas are widely used as a purported treatment for dysregulated glucose homeostasis. The objective of this study was to systematically evaluate the clinical and cellular-metabolic evidence, published between January 2013 and May 2019, and indexed on PubMed, ScienceDirect, and Web of Science, supporting the use of leaf teas for this purpose. Fourteen randomized controlled trials (RCTs) (13 on Camellia sinensis teas) were included, with mixed results, and providing scant mechanistic information. In contrast, 74 animal and cell culture studies focusing on the pancreas, liver, muscle, and adipose tissue yielded mostly positive results and highlighted enhanced insulin signaling as a recurring target associated with the effects of teas on glucose metabolism. We conclude that more studies, including RCTs and pre-clinical studies examining teas from a wider variety of species beyond C. sinensis, are required to establish a stronger evidence base on the use of leaf teas to normalize glucose metabolism.

Effects of green tea or green tea catechin on liver enzymes in healthy individuals and people with nonalcoholic fatty liver disease: A systematic review and meta-analysis of randomized clinical trials

The therapeutic potential of green tea as a rich source of antioxidants and anti-inflammatory compounds has been investigated by several studies. The present study aimed to systematically review and analyze randomized clinical trials (RCTs) assessing the effects of green tea, catechin, and other forms of green tea supplementation on levels of liver enzymes. PubMed, SCOPUS, EMBASE, and Cochrane databases were searched until February 2019. All RCTs investigating the effect of green tea or its catechin on liver enzymes including alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and bilirubin were included. A total of 15 RCTs were included. The overall effect of green tea on liver enzymes was nonsignificant (ALT [Standardized mean difference (SMD)= -0.17, CI -0.42 to 0.08, p = .19], AST [SMD = -0.07, CI -0.43 to 0.29, p = .69], and ALP [SMD = -0.17, CI -0.45 to 0.1, p = .22]). However, subgroup analyses showed that green tea reduced the levels of liver enzymes in participants with nonalcoholic fatty liver disease (NAFLD) but in healthy subjects, a small significant increase in liver enzymes was observed. In conclusion, the results of this study suggest that the effect of green tea on liver enzymes is dependent on the health status of individuals. While a moderate reducing effect was observed in patients with NAFLD, in healthy subjects, a small increasing effect was found.

Targeting obesity with plant-derived pancreatic lipase inhibitors: A comprehensive review

The prevalence of obesity is alarmingly increasing in the last few decades and leading to many serious public health concerns worldwide. The dysregulated lipid homeostasis due to various genetic, environmental and lifestyle factors is considered one of the critical putative pathways mediating obesity. Nonetheless, the scientific advancements unleashing the molecular dynamics of lipid metabolism have provided deeper insights on the emerging roles of lipid hydrolysing enzymes, including pancreatic lipase. It is hypothesized that inhibiting pancreatic lipase would prevent the breakdown of triglyceride and delays the absorption of fatty acids into the systemic circulation and adipocytes. Whilst, orlistat is the only conventional pancreatic lipase enzyme inhibitor available in clinics, identifying the safe clinical alternatives from plants to inhibit pancreatic lipase has been considered a significant advancement. Consequently, plants which have shown significant potential to combat obesity are now revisited for its abilities to inhibit pancreatic lipase. In this regard, our review surveyed the potential of medicinal plants and its phytoconstituents to inhibit pancreatic lipase and to elicit anti-obesity effects. Thus, the review collate and critically appraise the potential of medicinal plants and phyto-molecules inhibiting pancreatic lipase enzyme and consequently modulating triglyceride absorption in gut, and discuss its implications in the development of novel therapeutic strategies to combat obesity.

Effect of the herbal medicines in obesity and metabolic syndrome: A systematic review and meta-analysis of clinical trials

Obesity is a medical situation in which excess body fat has gathered because of imbalance between energy intake and energy expenditure. In spite of the fact that the variety of studies are available for obesity treatment and management, its "globesity" still remains a big challenge all over the world. The current systematic review and meta-analysis aimed to evaluate the efficacy, safety, and mechanisms of effective herbal medicines in the management and treatment of obesity and metabolic syndrome in human. We systematically searched all relevant clinical trials via Web of Science, Scopus, PubMed, and the Cochrane database to assess the effects of raw or refined products derived from plants or parts of plants on obesity and metabolic syndrome in overweight and obesity adult subjects. All studies conducted by the end of May 2019 were considered in the systematic review. Data were extracted independently by two experts. The quality assessment was assessed using Consolidated Standards of Reporting Trials checklist. The main outcomes were anthropometric indices and metabolic syndrome components. Pooled effect of herbal medicines on obesity and metabolic syndrome were presented as standardized mean difference (SMD) and 95% confidence interval (CI). A total of 279 relevant clinical trials were included. Herbals containing green tea, Phaseolus vulgaris, Garcinia cambogia, Nigella sativa, puerh tea, Irvingia gabonensis, and Caralluma fimbriata and their active ingredients were found to be effective in the management of obesity and metabolic syndrome. In addition, C. fimbriata, flaxseed, spinach, and fenugreek were able to reduce appetite. Meta-analysis showed that intake of green tea resulted in a significant improvement in weight ([SMD]: -0.75 [-1.18, -0.319]), body mass index ([SMD]: -1.2 [-1.82, -0.57]), waist circumference ([SMD]: -1.71 [-2.66, -0.77]), hip circumference ([SMD]: -0.42 [-1.02, -0.19]), and total cholesterol, ([SMD]: -0.43 [-0.77, -0.09]). In addition, the intake of P. vulgaris and N. sativa resulted in a significant improvement in weight ([SMD]: -0.88, 95 % CI: [-1.13, -0.63]) and triglyceride ([SMD]: -1.67, 95 % CI: [-2.54, -0.79]), respectively. High quality trials are still needed to firmly establish the clinical efficacy of the plants in obesity and metabolic syndrome.

Interactions of tea catechins with intestinal microbiota and their implication for human health

Tea catechins have attracted strong interests in pharmacological field for their extensive biological activities; however, their bioavailability in vivo is relatively low. Recent studies have shown tea catechins can modulate the composition of intestinal microbiota and help to improve hosts' health. Meanwhile, the gut flora plays a crucial role in regulating the production of the metabolites of tea catechins and their biological activity. Although the activities of tea catechins to promote intestinal micro-ecology have been extensively studied, little is known about the two-way phenol-microbial interactions. This review focuses on the modulatory effect of tea catechins on intestinal microbiota as well as the microbial degradation of tea catechins and the metabolites formed. Finally, the potential effects of tea catechins on chronic intestinal inflammation are emphasized.

Targeting Inflammation by Flavonoids: Novel Therapeutic Strategy for Metabolic Disorders

A balanced metabolic profile is essential for normal human physiological activities. Disproportions in nutrition give rise to imbalances in metabolism that are associated with aberrant immune function and an elevated risk for inflammatory-associated disorders. Inflammation is a complex process, and numerous mediators affect inflammation-mediated disorders. The available clinical modalities do not effectively address the underlying diseases but rather relieve the symptoms. Therefore, novel targeted agents have the potential to normalize the metabolic system and, thus, provide meaningful therapy to the underlying disorder. In this connection, polyphenols, the well-known and extensively studied phytochemical moieties, were evaluated for their effective role in the restoration of metabolism via various mechanistic signaling pathways. The various flavonoids that we observed in this comprehensive review interfere with the metabolic events that induce inflammation. The mechanisms via which the polyphenols, in particular flavonoids, act provide a promising treatment option for inflammatory disorders. However, detailed clinical studies of such molecules are required to decide their clinical fate.

Does tea extract supplementation benefit metabolic syndrome and obesity? A systematic review and meta-analysis

BACKGROUND

Given the global epidemic of obesity, numerous strategies have been employed in the management of metabolic syndrome (MS) in this population. A meta-analysis was designed in the present investigation to evaluate the benefits of tea extract (TE) supplementation in MS in obesity.

METHODS

We conducted searches of published literature in MEDLINE, PsycINFO, Scopus, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) databases from inception in 1985 to May 2017. Randomized controlled trials (RCTs) which studied TE consumption in obesity with MS were analyzed. Results were summarized using weighted mean differences (WMDs), standardized mean differences (SMDs) or odds ratio (OR) by suitable effect model.

RESULTS

Sixteen eligible randomized controlled trials, including 1090 subjects were identified. Benefits were demonstrated on reduction of Body Mass Index (BMI) (SMD, -0.27; 95% CI, -0.40 to -0.15, P < 0.0001) and blood glucose (SMD, -0.22; 95% CI, -0.34 to -0.10, P = 0.0003), and increasing high-density lipoprotein (HDL) (SMD, 0.18; 95% CI, 0.01 to 0.35, P = 0.03). Limited benefits without significance were observed on blood pressure and other anthropometric, cholesterol, and biochemistry outcomes. All-cause adverse events were minimal (0.99; 95% CI: 0.55, 1.77, P = 0.97).

CONCLUSIONS

This meta-analysis suggests that consumption of TE supplementation in the obese with MS has beneficial effects on improvement of lipid and glucose metabolism, as well as in the facilitation of weight loss.

Studies on the Prevention of Cancer and Cardiometabolic Diseases by Tea: Issues on Mechanisms, Effective Doses, and Toxicities

This article presents a brief overview of studies on the prevention of cancer and cardiometabolic diseases by tea. The major focus is on green tea catechins concerning the effective doses used, the mechanisms of action, and possible toxic effects. In cancer prevention by tea, the laboratory results are strong; however, the human data are inconclusive, and the effective doses used in some human trials approached toxic levels. In studies of the alleviation of metabolic syndrome, diabetes, and prevention of cardiovascular diseases, the results from human studies are stronger in individuals who consume 3-4 cups of tea (600-900 mg of catechins) or more per day. The tolerable upper intake level of tea catechins has been set at 300 mg of (-)-epigallocatechin-3-gallate in a bolus dose per day in some European countries. The effects of doses and dosage forms on catechin toxicity, the mechanisms involved, and factors that may affect toxicity are discussed.

Self-treatment with herbal products for weight-loss among overweight and obese subjects from central Mexico

ETHNOPHARMACOLOGICAL RELEVANCE

Mexico ranks second in the world for obesity prevalence. In Mexico, obese and overweight subjects commonly seek alternative treatments for weight-loss, including the use of herbal products.

AIM OF THE STUDY

The main objective of this study was to evaluate the prevalence of self-medication with herbal products for weight-loss among overweight and obese subjects residing in four states (Guanajuato, San Luis Potosi, State of Mexico, and Mexico City) from central Mexico. In addition, the factors related to self-medication among patients were studied.

MATERIALS AND METHODS

A total of 1404 overweight and obese subjects were interviewed. A chi-square test examined associations between socio-demographic and socio-economic information, and self-medication with herbal products for weight-loss.

RESULTS

The prevalence of self-medication was 42.9% among the participants who used herbal products for weight-loss. The female gender was the strongest factor (OR: 2.20 (1.75-2.77) associated with self-medication for weight-loss, followed by a low educational level (elementary and middle school) [OR: 1.80 (1.31-2.44)], and a middle-socioeconomic status [OR: 1.75 (1.21-2.52)]. The main herbal products used for weight-loss were based on: i) green tea, Camellia sinensis (12.7% of frequency), ii) aceitilla, Bidens odorata (6.6%), and iii) soybean, Glycine max (5.3%). In addition, 65% of the respondents considered herbal products ineffective for weight-loss after 6 months of use.

CONCLUSION

Due to the high incidence of overweight and obesity in Mexico, there is a high prevalence (42.9%) of self-medication using natural products for weight-loss, particularly in women from Central Mexico. This study indicates the important need to educate patients about the harmful effects of consuming these products.

The role of bioactives in energy metabolism and metabolic syndrome

Some food bioactives potentially exert anti-obesity effects. Anthocyanins (ACN), catechins, β-glucan (BG) and n-3 long chain PUFA (LCPUFA) are among the most promising candidates and have been considered as a strategy for the development of functional foods counteracting body weight gain. At present, clinical trials, reviews and meta-analyses addressing anti-obesity effects of various bioactives or bioactive-rich foods show contradictory results. Abdominal obesity is an important criterion for metabolic syndrome (MetS) diagnosis along with glucose intolerance, dyslipidaemia and hypertension. Food bioactives are supposed to exert beneficial effects on these parameters, therefore representing alternative therapy approaches for the treatment of MetS. This review summarises outcomes on MetS biomarkers in recent clinical trials supplementing ACN, catechins, BG and n-3 LCPUFA, focusing mainly on anti-obesity effects. Overall, it is clear that the level of evidence for the effectiveness varies not only among the different bioactives but also among the different putative health benefits suggested for the same bioactive. Limited evidence may be due to the low number of controlled intervention trials or to inconsistencies in trial design, i.e. duration, dose and/or the method of bioactive supplementation (extracts, supplements, rich or enriched food). At present, the question 'Are bioactives effective in weight management and prevention of metabolic syndrome?' remains inconclusive. Thus, a common effort to harmonise the study design of intervention trials focusing on the most promising bioactive molecules is urgently needed to strengthen the evidence of their potential in the treatment of obesity, MetS and related diseases.

Caloric Restriction Mimetics against Age-Associated Disease: Targets, Mechanisms, and Therapeutic Potential

The increase in life expectancy has boosted the incidence of age-related pathologies beyond social and economic sustainability. Consequently, there is an urgent need for interventions that revert or at least prevent the pathogenic age-associated deterioration. The permanent or periodic reduction of calorie intake without malnutrition (caloric restriction and fasting) is the only strategy that reliably extends healthspan in mammals including non-human primates. However, the strict and life-long compliance with these regimens is difficult, which has promoted the emergence of caloric restriction mimetics (CRMs). We define CRMs as compounds that ignite the protective pathways of caloric restriction by promoting autophagy, a cytoplasmic recycling mechanism, via a reduction in protein acetylation. Here, we describe the current knowledge on molecular, cellular, and organismal effects of known and putative CRMs in mice and humans. We anticipate that CRMs will become part of the pharmacological armamentarium against aging and age-related cardiovascular, neurodegenerative, and malignant diseases.

Effect of green tea consumption on the metabolic syndrome indices in women: a clinical trial study

Purpose

Metabolic syndrome (MetS) is a complex disorder that exacerbates the risk of cardiovascular disease and diabetes mellitus; some studies have indicated the beneficial effects of green tea on human health. The purpose of this study is to investigate the effects of green tea consumption on the MetS indicators in women.

Design/methodology/approach

A randomized clinical trial was carried out on 70 eligible women with confirmed diagnosis of MetS who visited Shabani Diabetes Clinic (Isfahan, Iran). Participants were randomly divided into two groups. Participants in the Green Tea Group were asked to consume three 200 cc of green tea in the morning, at noon and at night for eight weeks, while people in the control group were asked to take identical amount of lukewarm water at the same schedule. Anthropometric indicators, blood pressure, blood sugar, lipid profile, diet and physical activity were assessed at the beginning and the end of the study.

Findings

An independentt-test showed that weight (p =0.001), body mass index (p =0.001), waist circumference (p< 0.001) and waist–hip ratio (p =0.02), systolic blood pressure (p =0.04), fasting blood glucose (p =0.01) and low density lipoprotein (p =0.03) changed significantly more in the Green Tea Group than in the control group; but no such inter-group difference was observed in diastolic blood pressure, triglyceride, total cholesterol and high density lipoprotein (HDL) values (p> 0.05).

Originality/value

Regular consumption of green tea for eight weeks significantly improved anthropometric indices, blood pressure, blood sugar and lipid profile in women with MetS. Therefore, this beverage can serve as part of an effective dietary strategy to control MetS.

Cardiovascular Effects of Flavonoids

:

Cardiovascular Disease (CVD) is the major cause of death worldwide, especially in Western society. Flavonoids are a large group of polyphenolic compounds widely distributed in plants, present in a considerable amount in fruit and vegetable. Several epidemiological studies found an inverse association between flavonoids intake and mortality by CVD. The antioxidant effect of flavonoids was considered the main mechanism of action of flavonoids and other polyphenols. In recent years, the role of modulation of signaling pathways by direct interaction of flavonoids with multiple protein targets, namely kinases, has been increasingly recognized and involved in their cardiovascular protective effect. There are strong evidence, in in vitro and animal experimental models, that some flavonoids induce vasodilator effects, improve endothelial dysfunction and insulin resistance, exert platelet antiaggregant and atheroprotective effects, and reduce blood pressure. Despite interacting with multiple targets, flavonoids are surprisingly safe. This article reviews the recent evidence about cardiovascular effects that support a beneficial role of flavonoids on CVD and the potential molecular targets involved.

Changes in Plasma Metabolites Concentrations in Obese Dogs Supplemented With Anti-oxidant Compound

The aim of this study is to discuss the effect of anti-oxidant supplement (Rv-PEM01-99, Kibun Foods, Inc., Tokyo, Japan) on changes in energy metabolism in obese dogs. 200 mg/kg/day of Rv-PEM01-99 (equivalent to 5 mg kg/day of quercetin derivative) were applied for 6 weeks to the Beagle dogs fed high fat diet (HFD) or control diet (CD). In the present study, body weight (BW) decreasing effect of Rv-PEM 01-99 in obese dogs was not clear. However, plasma alkaline phosphatase (ALP) activities at the end of experiment were significantly decreased compared to those at the start of experiment in obese dogs supplemented with Rv-PEM 01-99 (paired-t test, p < 0.05). In control dogs supplemented with Rv-PEM 01-99, Plasma malondialdehyde (MDA), and triglycerides (TG) levels and lactate dehydrogenase (LDH) activities were significantly decreased compared to those at the start of experiment (paired-t test, p < 0.05). From these findings, Rv-PEM 01-99 seems to be not harmful for dogs. Anti-lipid peroxide effect and liver function improvement are expected in the dogs supplemented with Rv-PEM 01-99.

Flavanols are potential anti-obesity agents, a systematic review and meta-analysis of controlled clinical trials

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.

The effects of polyphenol supplementation on adipose tissue morphology and gene expression in overweight and obese humans

Dietary polyphenols have beneficial effects on adipose tissue mass and function in rodents, but human studies are scarce. In a randomized, placebo-controlled study, 25 (10 women) overweight and obese humans received a combination of the polyphenols epigallocatechin-gallate and resveratrol (282 mg/d, 80 mg/d, respectively, EGCG+RES, n = 11) or placebo (PLA, n = 14) supplementation for 12 weeks. Abdominal subcutaneous adipose tissue (SAT) biopsies were collected for assessment of adipocyte morphology and micro-array analysis. EGCG+RES had no effects on adipocyte size and distribution compared with PLA. However, we identified pathways contributing to adipogenesis, cell cycle and apoptosis were significantly downregulated by EGCG+RES versus PLA. Furthermore, EGCG+RES significantly decreased expression of pathways related to energy metabolism, oxidative stress, inflammation, and immune defense as compared with PLA. In conclusion, the SAT gene expression profile indicates a reduced cell turnover after 12-week EGCG+RES in overweight-obese subjects. It remains to be elucidated whether these alterations translate into long-term metabolic effects.

A Review on the Weight-Loss Effects of Oxidized Tea Polyphenols

The mechanistic systems in the body through which tea causes weight loss are complex and multi-dimensional. Additionally, the bioactive components in tea such as catechins, caffeine, and products of tea polyphenol oxidation vary greatly from one major tea type to the next. Green tea has been the primary subject of consideration for investigation into the preventative health effects of tea because it contains the highest levels of phenolic compounds and retains the highest antioxidant capabilities of any major tea type. However, recent research suggests decreasing body fat accumulation has little to do with antioxidant activity and more to do with enzyme inhibition, and gut microbiota interactions. This paper reviews several different tea polyphenol-induced weight-loss mechanisms, and purposes a way in which these mechanisms may be interrelated. Our original 'short-chain fatty acid (SCFA) hypothesis' suggests that the weight-loss efficacy of a given tea is determined by a combination of carbohydrate digestive enzyme inhibition and subsequent reactions of undigested carbohydrates with gut microbiota. These reactions among residual carbohydrates, tea polyphenols, and gut microbiota within the colon produce short-chain fatty acids, which enhance lipid metabolism through AMP-activated protein kinase (AMPK) activation. Some evidence suggests the mechanisms involved in SCFA generation may be triggered more strongly by teas that have undergone fermentation (black, oolong, and dark) than by non-fermented (green) teas. We discussed the mechanistic differences among fermented and non-fermented teas in terms of enzyme inhibition, interactions with gut microbiota, SCFA generation, and lipid metabolism. The inconsistent results and possible causes behind them are also discussed.

Scientific opinion on the safety of green tea catechins

The EFSA ANS Panel was asked to provide a scientific opinion on the safety of green tea catechins from dietary sources including preparations such as food supplements and infusions. Green tea is produced from the leaves of Camellia sinensis (L.) Kuntze, without fermentation, which prevents the oxidation of polyphenolic components. Most of the polyphenols in green tea are catechins. The Panel considered the possible association between the consumption of (-)-epigallocatechin-3-gallate (EGCG), the most relevant catechin in green tea, and hepatotoxicity. This scientific opinion is based on published scientific literature, including interventional studies, monographs and reports by national and international authorities and data received following a public 'Call for data'. The mean daily intake of EGCG resulting from the consumption of green tea infusions ranges from 90 to 300 mg/day while exposure by high-level consumers is estimated to be up to 866 mg EGCG/day, in the adult population in the EU. Food supplements containing green tea catechins provide a daily dose of EGCG in the range of 5-1,000 mg/day, for adult population. The Panel concluded that catechins from green tea infusion, prepared in a traditional way, and reconstituted drinks with an equivalent composition to traditional green tea infusions, are in general considered to be safe according to the presumption of safety approach provided the intake corresponds to reported intakes in European Member States. However, rare cases of liver injury have been reported after consumption of green tea infusions, most probably due to an idiosyncratic reaction. Based on the available data on the potential adverse effects of green tea catechins on the liver, the Panel concluded that there is evidence from interventional clinical trials that intake of doses equal or above 800 mg EGCG/day taken as a food supplement has been shown to induce a statistically significant increase of serum transaminases in treated subjects compared to control.

The safety of green tea and green tea extract consumption in adults - Results of a systematic review

A systematic review of published toxicology and human intervention studies was performed to characterize potential hazards associated with consumption of green tea and its preparations. A review of toxicological evidence from laboratory studies revealed the liver as the target organ and hepatotoxicity as the critical effect, which was strongly associated with certain dosing conditions (e.g. bolus dose via gavage, fasting), and positively correlated with total catechin and epigallocatechingallate (EGCG) content. A review of adverse event (AE) data from 159 human intervention studies yielded findings consistent with toxicological evidence in that a limited range of concentrated, catechin-rich green tea preparations resulted in hepatic AEs in a dose-dependent manner when ingested in large bolus doses, but not when consumed as brewed tea or extracts in beverages or as part of food. Toxico- and pharmacokinetic evidence further suggests internal dose of catechins is a key determinant in the occurrence and severity of hepatotoxicity. A safe intake level of 338 mg EGCG/day for adults was derived from toxicological and human safety data for tea preparations ingested as a solid bolus dose. An Observed Safe Level (OSL) of 704 mg EGCG/day might be considered for tea preparations in beverage form based on human AE data.

Molecular understanding of Epigallocatechin gallate (EGCG) in cardiovascular and metabolic diseases

ETHNOPHARMACOLOGICAL RELEVANCE

The compound epigallocatechin-3-gallate (EGCG), the major polyphenolic compound present in green tea [Camellia sinensis (Theaceae], has shown numerous cardiovascular health promoting activity through modulating various pathways. However, molecular understanding of the cardiovascular protective role of EGCG has not been reported.

AIM OF THE REVIEW

This review aims to compile the preclinical and clinical studies that had been done on EGCG to investigate its protective effect on cardiovascular and metabolic diseases in order to provide a systematic guidance for future research.

MATERIALS AND METHODS

Research papers related to EGCG were obtained from the major scientific databases, for example, Science direct, PubMed, NCBI, Springer and Google scholar, from 1995 to 2017.

RESULTS

EGCG was found to exhibit a wide range of therapeutic properties including anti-atherosclerosis, anti-cardiac hypertrophy, anti-myocardial infarction, anti-diabetes, anti-inflammatory and antioxidant. These therapeutic effects are mainly associated with the inhibition of LDL cholesterol (anti-atherosclerosis), inhibition of NF-κB (anti-cardiac hypertrophy), inhibition of MPO activity (anti-myocardial infarction), reduction in plasma glucose and glycated haemoglobin level (anti-diabetes), reduction of inflammatory markers (anti-inflammatory) and the inhibition of ROS generation (antioxidant).

CONCLUSION

EGCG shows different biological activities and in this review, a compilation of how this bioactive molecule plays its role in treating cardiovascular and metabolic diseases was discussed.

Studies on prevention of obesity, metabolic syndrome, diabetes, cardiovascular diseases and cancer by tea

Tea, a popular beverage made from leaves of the plant Camellia sinensis, has been studied extensively in recent decades for its beneficial health effects in the prevention of obesity, metabolic syndrome, diabetes, cancer, and other diseases. Whereas these beneficial effects have been convincingly demonstrated in most laboratory studies, results from human studies have not been consistent. Some studies demonstrated that weight reduction, alleviation of metabolic syndrome and risk reduction in diabetes were only observed in individuals who consume 3-4 cups of tea (600-900 mg tea catechins) or more daily. This chapter reviews some of these studies, the possible mechanisms of actions of tea constituents, and the challenges in extrapolating laboratory studies to human situations.

Phenolic compounds as natural and multifunctional anti-obesity agents: A review

Prevalence of obesity worldwide has reached pandemic proportions. Despite the increasing evidence in the implication of phenolic compounds in obesity management, the real effect is not completely understood. The available in vitro and in vivo studies have demonstrated the implication of phenolic compounds in: lowering food intake, decreasing lipogenesis, increasing lipolysis, stimulating fatty acids β-oxidation, inhibiting adipocyte differentiation and growth, attenuating inflammatory responses and suppress oxidative stress. This review encompasses the most recent evidence in the anti-obesity effect of phenolic compounds from plants to different nutraceuticals and functional foods based on the in vitro, in vivo and clinical studies. For that, this review has been focused on popular plant-based products highly consumed today such as cocoa, cinnamon, and olive oil, beverages such as red wine, tea (green, white and black tea) and Hibiscus sabdariffa L. tea, among others.

Potential Biological Effects of (-)-Epigallocatechin-3-gallate on the Treatment of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a major health issue throughout the world. However, no validated treatments for NAFLD are currently available. In‐depth studies have demonstrated the efficacy of (‐)‐epigallocatechin‐3‐gallate (EGCG), a main bioactive chemical extracted from green tea, in treating NAFLD. EGCG exhibits multi‐pronged preventive and therapeutic activities, including promoting lipid and glucose metabolism, anti‐lipid peroxidation and anti‐inflammation activities, anti‐fibrosis, and anti‐NAFLD related tumor, thus contributing to the mitigation of NAFLD occurrence and progression. The objectives of this paper are to review and discuss the currently known targets, signaling pathways and roles of EGCG that interfere with NAFLD pathogenesis, then providing additional experimental evidence and the foundation for the further studies and clinical applications of EGCG in the prevention and treatment of NAFLD.

Effects of green tea on lipid metabolism in overweight or obese people: A meta-analysis of randomized controlled trials

SCOPE

The effects of green tea on lipid metabolism were inconsistent. The objective of this meta-analysis was to evaluate the effects of green tea on lipid metabolism in overweight or obese people.

METHODS AND RESULTS

We searched randomized controlled trials (RCTs) comparing green tea with a control on lipid metabolism on PUBMED and WEB OF SCIENCE (January 1990 to September 2016), COCHRANE and EMBASE (updated to October 2016), and the Chinese databases CNKI, WanFang and CBMD. Twenty-one articles studying 1704 overweight or obese subjects were selected for this meta-analysis. The pooled results demonstrated that green tea significantly decreased plasma total cholesterol (TC) and low-density lipoprotein cholesterol (LDL) levels in overweight or obese people. The weighted mean difference was -3.38 mg/dl for TC (95% CI: -6.42,  -0.33 mg/dL) and -5.29 mg/dL for LDL (95% CI: -7.92, -2.6 6 mg/dL), respectively. Green tea intake, however, showed no effect on plasma triglyceride (TG) and high-density lipoprotein cholesterol(HDL) levels in overweight or obese people with a relatively high heterogeneity.

CONCLUSION

The meta-analysis shows that drinking green tea can lower plasma TC and LDL levels significantly. Nevertheless, green tea's effect on plasma TG and HDL must be further evaluated by additional high-quality and large-scale RCTs.

A Systematic Review and Meta-Analysis of the Effects of Flavanol-Containing Tea, Cocoa and Apple Products on Body Composition and Blood Lipids: Exploring the Factors Responsible for Variability in Their Efficacy

Several randomized controlled trials (RCTs) and meta-analyses support the benefits of flavanols on cardiometabolic health, but the factors affecting variability in the responses to these compounds have not been properly assessed. The objectives of this meta-analysis were to systematically collect the RCTs-based-evidence of the effects of flavanol-containing tea, cocoa and apple products on selected biomarkers of cardiometabolic risk and to explore the influence of various factors on the variability in the responses to the consumption of these products. A total of 120 RCTs were selected. Despite a high heterogeneity, the intake of the flavanol-containing products was associated using a random model with changes (reported as standardized difference in means (SDM)) in body mass index (−0.15, p < 0.001), waist circumference (−0.29, p < 0.001), total-cholesterol (−0.21, p < 0.001), LDL-cholesterol (−0.23, p < 0.001), and triacylglycerides (−0.11, p = 0.027), and with an increase of HDL-cholesterol (0.15, p = 0.005). Through subgroup analyses, we showed the influence of baseline-BMI, sex, source/form of administration, medication and country of investigation on some of the outcome measures and suggest that flavanols may be more effective in specific subgroups such as those with a BMI ≥ 25.0 kg/m², non-medicated individuals or by specifically using tea products. This meta-analysis provides the first robust evidence of the effects induced by the consumption of flavanol-containing tea, cocoa and apple products on weight and lipid biomarkers and shows the influence of various factors that can affect their bioefficacy in humans. Of note, some of these effects are quantitatively comparable to those produced by drugs, life-style changes or other natural products. Further, RCTs in well-characterized populations are required to fully comprehend the factors affecting inter-individual responses to flavanol and thereby improve flavanols efficacy in the prevention of cardiometabolic disorders.

Long-term supplementation of decaffeinated green tea extract does not modify body weight or abdominal obesity in a randomized trial of men at high risk for prostate cancer

Background

Evidence continues to demonstrate the role of obesity in prostate carcinogenesis and prognosis, underscoring the need to identify and continue to evaluate the effective interventions to reduce obesity in populations at high risk. The aim of the study was to determine the effect of daily consumption of decaffeinated green tea catechins (GTC) formulation (Polyphenon E^® (PolyE)) for 1 year on biomarkers of obesity in men who are at high risk for prostate cancer.

Materials and Methods

A randomized, double-blinded trial was conducted targeting 97 men diagnosed with HGPIN or ASAP. Subjects were randomized to receive GTC (PolyE) (n = 49) or placebo (n = 48) for 1 year. Anthropometric data were collected at baseline, 6 and 12 months and data analyzed to observe change in weight, body mass index (indicator of obesity) and waist: hip ratio (indicator of abdominal obesity).

Results

Decaffeinated GTC containing 400 mgs of the bioactive catechin, EGCG administered for 1 year to men diagnosed with ASAP and HGPIN appears to be bioavailable, well tolerated but not effective in reducing biomarkers of obesity including body weight, body mass index and waist: hip ratio.

Conclusions

The results of our trial demonstrates that men who are obese and at high risk for prostate cancer should resort to effective weight management strategies to reduce obesity and not resort to ineffective measures such as taking supplements of green tea to reduce biomarkers of obesity. Changes in body mass index and abdominal obesity seen in other studies were potentially due to caffeine and not GTC.

The Effect of Dietary Supplements Containing Green Tea, Capsaicin and Ginger Extracts on Weight Loss and Metabolic Profiles in Overweight Women: A Randomized Double-Blind Placebo-Controlled Clinical Trial

BACKGROUND

This study was conducted to determine the effects of dietary supplements containing green tea, capsaicin and ginger extracts on weight loss and metabolic profiles among overweight women.

METHODS

This randomized double-blind placebo-controlled clinical trial was implemented among 50 overweight women. Participants were randomly divided into 2 groups. Group A received dietary supplements containing 125 mg green tea, 25 mg capsaicin and 50 mg ginger extracts (n = 25) group B received placebos (n = 25) twice with lunch and twice with dinner daily for 8 weeks.

RESULTS

Compared with placebo, taking dietary supplements containing green tea, capsaicin and ginger resulted in a significant decrease in weight (-1.8 ± 1.5 vs. +0.4 ± 1.2 kg, respectively, p < 0.001) and body mass index (BMI; -0.7 ± 0.5 vs. +0.1 ± 0.5 kg/m2, respectively, p < 0.001). In addition, subjects who received green tea, capsaicin and ginger co-supplements had significantly decreased serum insulin concentrations (-2.6 ± 3.9 vs. -0.6 ± 2.0 µIU/mL, p = 0.02), homeostatic model of assessment for insulin resistance (-0.5 ± 0.8 vs. -0.05 ± 0.6, p = 0.01), and increased quantitative insulin sensitivity check index (+0.01 ± 0.01 vs. +0.001 ± 0.01, p = 0.008) and plasma glutathione (GSH) levels (+73.8 ± 120.6 vs. -28.3 ± 193.4 µmol/L, p = 0.03) compared with the placebo.

CONCLUSIONS

Our study indicated that taking green tea, capsaicin and ginger co-supplements for 8 weeks among overweight women had beneficial effects on weight, BMI, markers of insulin metabolism and plasma GSH levels.

The Combination of Green Tea Extract and Eriodictyol Inhibited High-Fat/High-Sucrose Diet-Induced Cholesterol Upregulation Is Accompanied by Suppression of Cholesterol Synthesis Enzymes

Western diets induce obesity associated with an increased risk of hypercholesterolaemia. Indeed, obesity-induced hypercholesterolaemia is correlated with increased coronary cardiovascular disease (CVD) risk. Male C57BL/6J mice were fed a normal diet, high-fat and high-sucrose diet (HF/HS), HF/HS with green tea extract powder diet (HF/HS+GT), HF/HS with eriodictyol diet (HF/HS+Eri), or HF/HS with green tea extract powder and eriodictyol diet (HF/HS+GT+Eri) for 8 wk. Body weight was lower in the HF/HS+GT+Eri group than in the HF/HS group (-8.3%, p<0.01). The HF/HS diet elicited an upregulation of total cholesterol levels (-63%, p<0.001), and low-density lipoprotein (LDL) levels (-89%, p<0.001) were significantly suppressed by the GT+Eri diet. Conversely, no change (p>0.05) was observed in the HF/HS+GT and HF/HS+Eri groups. The HF/HS diet-induced hepatic mRNA increase in 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) was ameliorated (-73%) by the oral administration of green tea extract and eriodictyol. Moreover, the GT+Eri diet suppressed HF/HS diet-induced upregulation of 3-hydroxy-3-methylglutaryl-coenzyme A synthase (HMGCS) (-75%, p<0.05). Furthermore, the LDL receptor (LDLR) levels were higher in the HF/HS+GT+Eri group (+50%, p<0.05) than in the HF/HS group. These results suggest that a combination of green tea and eriodictyol decreases cholesterol levels, particularly LDL levels, accompanied by the suppression of HMGCR and HMGCS levels and upregulation of LDLR levels in the liver.

Anti-obesogenic and antidiabetic effects of plants and mushrooms

Obesity is reaching global epidemic proportions as a result of factors such as high-calorie diets and lack of physical exercise. Obesity is now considered to be a medical condition, which not only contributes to the risk of developing type 2 diabetes mellitus, cardiovascular disease and cancer, but also negatively affects longevity and quality of life. To combat this epidemic, anti-obesogenic approaches are required that are safe, widely available and inexpensive. Several plants and mushrooms that are consumed in traditional Chinese medicine or as nutraceuticals contain antioxidants, fibre and other phytochemicals, and have anti-obesogenic and antidiabetic effects through the modulation of diverse cellular and physiological pathways. These effects include appetite reduction, modulation of lipid absorption and metabolism, enhancement of insulin sensitivity, thermogenesis and changes in the gut microbiota. In this Review, we describe the molecular mechanisms that underlie the anti-obesogenic and antidiabetic effects of these plants and mushrooms, and propose that combining these food items with existing anti-obesogenic approaches might help to reduce obesity and its complications.

The Impact of Green Tea Supplementation on Anthropometric Indices and Inflammatory Cytokines in Women with Polycystic Ovary Syndrome

The present study aimed to determine the effect of a green tea supplement on anthropometric indices and inflammatory factors in women with polycystic ovary syndrome (PCOS). In this randomized clinical trial, 45 women with PCOS were randomly allocated into two groups receiving green tea tablets or placebo. The period of intervention was 45 days. The serum levels of interleukin 6, high-sensitivity C-reactive protein, and tumor necrosis factor α were measured before and after intervention period using the related kits. Anthropometric indices also were measured. The mean of body mass index, weight, waist circumference, and body fat percentage in the green tea group were reduced significantly. However, no significant difference was observed between the two groups. Also, there was no significant effect on the levels of inflammatory factors. The present results suggest that daily consumption of green tea tablets did not cause any effect on inflammation biomarkers in PCOS women. However, it may be effective as a complementary treatment for weight control in these women. Copyright © 2017 John Wiley & Sons, Ltd.

Phloretin Prevents High-Fat Diet-Induced Obesity and Improves Metabolic Homeostasis

Reactive oxygen species generated as a by-product in metabolism play a central role in the development of obesity and obesity-related metabolic complications. The objective of the current study is to explore the possibility to block obesity and improve metabolic homeostasis via phloretin, a natural antioxidant product from apple tree leaves and Manchurian apricot. Both preventive and therapeutic activities of phloretin were assessed using a high-fat diet-induced obesity mouse model. Phloretin was injected intraperitoneally twice weekly into regular and obese mice fed a high-fat diet. The effects of phloretin treatment on body weight and composition, fat content in the liver, glucose and lipid metabolism, and insulin resistance were monitored and compared to the control animals. Phloretin treatment significantly blocks high-fat diet-induced weight gain but did not induce weight loss in obese animals. Phloretin improved glucose homeostasis and insulin sensitivity and alleviated hepatic lipid accumulation. RT-PCR analysis showed that phloretin treatment suppresses expression of macrophage markers (F4/80 and Cd68) and pro-inflammatory genes (Mcp-1 and Ccr2) and enhances adiponectin gene expression in white adipose tissue. In addition, phloretin treatment elevated the expression of fatty acid oxidation genes such as carnitine palmitoyltransferase 1a and 1b (Cpt1a and Cpt1b) and reduced expression of monocyte chemoattractant protein-1 (Mcp-1), de novo lipogenesis transcriptional factor peroxisome proliferator-activated receptor-γ 2 (Pparγ2), and its target monoacylglycerol O-acyltransferase (Mgat-1) genes. These results provide direct evidence to support a possible use of phloretin for mitigation of obesity and maintenance of metabolic homeostasis.

Bioactive nutrients - Time for tolerable upper intake levels to address safety

There is increasing interest by consumers, researchers, and regulators into the roles that certain bioactive compounds, derived from plants and other natural sources, can play in health maintenance and promotion, and even prolonging a productive quality of life. Research has rapidly emerged suggesting that a wide range of compounds and mixtures in and from plants (such as fruits and vegetables, tea and cocoa) and animals (such as fish and probiotics) may exert substantial health benefits. There is interest in exploring the possibility of establishing recommended intakes or dietary guidance for certain bioactive substances to help educate consumers. A key aspect of establishing dietary guidance is the assessment of safety/toxicity of these substances. Toxicologists need to be involved in both the development of the safety framework and in the evaluation of the science to establish maximum intake/upper limits.

The enhanced anti-obesity effect and reduced gastric mucosa irritation of capsaicin-loaded nanoemulsions

Organogel-derived capsaicin nanoemulsions can inhibit diet-induced hepatic steatosis and reduce epididymal adipocyte size and tissue mass.

Effects of green tea catechin extract on serum lipids in postmenopausal women: a randomized, placebo-controlled clinical trial

BACKGROUND

Green tea has been suggested to improve cardiovascular disease risk factors, including circulating lipid variables. However, current evidence is predominantly based on small, short-term randomized controlled trials conducted in diverse populations.

OBJECTIVE

The aim of this study was to examine the efficacy and impact of green tea extract (GTE) supplementation high in epigallocatechin gallate (EGCG) on blood lipids in healthy postmenopausal women.

DESIGN

This was an ancillary study of a double-blind, randomized, placebo-controlled, parallel-arm trial investigating the effects of a GTE supplement containing 1315 mg catechins (843 mg EGCG) on biomarkers of breast cancer risk. Participants were randomly assigned to receive GTE (n = 538) or placebo (n = 537) and were stratified by catechol-O-methyltransferase (COMT) genotype activity (high COMT compared with low or intermediate COMT genotype activity). They consumed either 4 GTE or identical placebo capsules daily for 12 mo. A total of 936 women completed this substudy. Circulating lipid panels including total cholesterol (TC), HDL cholesterol, and triglycerides were measured at baseline and at months 6 and 12.

RESULTS

Compared with placebo, 1-y supplementation with GTE capsules resulted in a significant reduction in circulating TC (-2.1% compared with 0.7%; P = 0.0004), LDL cholesterol (-4.1% compared with 0.9%; P < 0.0001) and non-HDL cholesterol (-3.1% compared with 0.4%; P = 0.0032). There was no change in HDL-cholesterol concentration, but triglyceride concentrations increased by 3.6% in the GTE group, whereas they decreased by 2.5% in the placebo group (P = 0.046). A significant reduction in TC was observed only among women with high (i.e., ≥200 mg/dL) baseline TC concentrations (P-interaction = 0.01) who consumed GTE capsules. The effect of GTE on the increase in triglycerides was mainly observed among obese women and statin users (P-interaction = 0.06).

CONCLUSION

Supplementation with GTE significantly reduced circulating TC and LDL-cholesterol concentrations, especially in those with elevated baseline TC concentrations. This trial was registered at clinicaltrials.gov as NCT00917735.

Nrf2 signaling pathway: Pivotal roles in inflammation

Inflammation is the most common feature of many chronic diseases and complications, while playing critical roles in carcinogenesis. Several studies have demonstrated that Nrf2 contributes to the anti-inflammatory process by orchestrating the recruitment of inflammatory cells and regulating gene expression through the antioxidant response element (ARE). The Keap1 (Kelch-like ECH-associated protein)/Nrf2 (NF-E2 p45-related factor 2)/ARE signaling pathway mainly regulates anti-inflammatory gene expression and inhibits the progression of inflammation. Therefore, the identification of new Nrf2-dependent anti-inflammatory phytochemicals has become a key point in drug discovery. In this review, we discuss the members of the Keap1/Nrf2/ARE signal pathway and its downstream genes, the effects of this pathway on animal models of inflammatory diseases, and crosstalk with the NF-κB pathway. In addition we also discuss about the regulation of NLRP3 inflammasome by Nrf2. Besides this, we summarize the current scenario of the development of anti-inflammatory phytochemicals and others that mediate the Nrf2/ARE signaling pathway.

Physiological effects of epigallocatechin-3-gallate (EGCG) on energy expenditure for prospective fat oxidation in humans: A systematic review and meta-analysis

Green tea catechins (GTCs) are known to improve fat oxidation (FOX) during fasted, rested and exercise conditions wherein epigallocatechin-3-gallate (EGCG) is thought to be the most pharmacologically active and has been studied extensively. From the available data of randomized controlled trials (RCTs) on EGCG, we carried out a systematic review and meta-analysis to elucidate whether EGCG consumption indeed increase energy expenditure (EE) and promote FOX. A systematic review of the literature was conducted using electronic databases (PubMed, Embase, Cochrane Library, CINAHL, JICST, JSTPLUS, and JMEDPLUS and others) and eight RCTs were included. RCTs were reviewed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses 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), EE and rate of FOX to compare the EGCG and placebo treatments. The meta-analysis results of verities of studies in terms 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% confidence intervals (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, waist circumference and total body fat mass (TBFM) were also examined and their impact on the promotion of FOX is reported. Effect of EGCG doses was also systematically reviewed. Finding showed that EGCG intake moderately accelerates EE and reduces RQ. The analyses revealed that the EGCG resulted in difference in RQ and EE but the effect on the other measures of energy metabolism was relatively mild. Possibly, EGCG alone has the potential to increase metabolic rate at 300 mg dose. Collectively, the outcome supports the findings that EGCG has an effect on metabolic parameters. However, the large prospective trials are needed to confirm the findings.

Polyphenol-based nutraceuticals for the prevention and treatment of cardiovascular disease: Review of human evidence

BACKGROUND

In addition to prescription drugs, nutraceuticals/functional foods/medical foods are being increasingly added as adjunct treatment of cardiovascular disease (CVD), even though most of them have been exclusively studied in vitro.

HYPOTHESIS/PURPOSE

We review the available evidence (focusing on when the amount of polyphenols' intake was measured) coming from randomized controlled trials (RCTs) of (poly)phenol-based supplements.

CONCLUSION

We conclude that (poly)phenol-based nutraceuticals and functional foods might be indeed used as adjunct therapy of CVD, but additional long-term RCTs with adequate numerosity and with clinically relevant end points are needed to provide unequivocal evidence of their clinical usefulness.

Beneficial Effects of Tea and the Green Tea Catechin Epigallocatechin-3-gallate on Obesity

Green tea has been shown to have beneficial effects against cancer, obesity, atherosclerosis, diabetes, bacterial and viral infections, and dental caries. The catechin (−)-epigallocatechin-3-gallate (EGCG) has shown the highest biological activity among green tea catechins (GTCs) in most of the studies. While several epidemiological studies have shown the beneficial effects of tea and GTCs on obesity, some studies have failed to do this. In addition, a large number of interventional clinical studies have shown these favorable effects, and cellular and animal experiments have supported those findings, and revealed the underlying anti-obesity mechanisms. One of the mechanisms is enhanced cellular production of reactive oxygen species, which is mediated through the pro-oxidant action of EGCG, leading to the activation of adenosine monophosphate-activated protein kinase, which suppresses gene and protein expression of enzymes and transcription factors involved in adipogenesis and lipogenesis, and stimulates those involved in lipolysis. Recently, scientific evidence supporting the beneficial anti-obesity effects of green tea and GTCs has been increasing. However, future investigations are still required to clarify the reasons for the inconsistent results reported in the human studies; to achieve this, careful adjustment of confounding factors will be required.