乌龙茶水浸物对大鼠的减肥作用

[目的]探讨乌龙茶的减肥作用。[方法]选用SD雄性大鼠用高能量高脂肪饲料制备肥胖模型大鼠后,选择其中32只模型鼠,随机分为肥胖对照组、低、中、高剂量组,分别灌服蒸馏水、0.4g/kg.bw、1.2g/kg.bw、2.4g/kg.bw的乌龙茶水浸物30d后,测定体重、体脂及脂肪细胞最大径。[结果]30d后,灌服中、高剂量乌龙茶水浸物的大鼠体重、体重增加、体围、腹膜后与附睾周脂肪组织重量及脂肪系数、附睾周与肩胛间脂肪细胞的最大径明显低于肥胖对照组大鼠,而饲料总摄取量在各组间却无明显差异。中剂量大鼠腹膜后、肾周脂肪系数也明显低于低剂量组大鼠。[结论]乌龙茶具有减肥作用,中剂量可能为适宜剂量。     

绿茶有助减肥

美国宾夕法尼亚大学的研究人员近日报告说，他们以小鼠为模型进行的动物研究显示，绿茶中的一种名为EGCG的儿茶素可以抑制小鼠体重增加，该物质有望成为对抗肥胖的新制剂。     

青砖茶与绿茶对大鼠脂代谢和抗氧化作用的比较研究

目的分析了青砖茶及绿茶主要生化成分含量及其对大鼠减肥和抗氧化作用。方法选用2种贮藏时间的青砖茶和普通绿茶测定其主要化学成分,选取雄性Wistar大鼠60只,体重为80±5g,随机分为6组,每组10只。空白对照组和模型对照组每天灌胃蒸馏水;阳性对照组每天灌胃Orlistat 0.04g/kg·bw,1年砖剂量组、10年砖剂量组、绿茶剂量组每天灌胃1.5g/kg·bw的相应茶汤。除空白对照组喂饲普通饲料外,其它5组均喂饲高脂营养饲料,试验期6w。定期称体重,测体长,实验结束后颈动脉取血,测血脂及其抗氧化指标,观测大鼠体内脂肪沉着及脏器变化情况。结果 10年青砖茶茶多糖、茶褐素含量最高,其它成分含量最低,而绿茶茶多糖、茶褐素含量最低,其它成分含量最高。青砖茶、绿茶都能显著降低大鼠体重、Lee’s指数、脂肪系数及血脂水平,能显著提高血清HDL-C含量及血清、肝脏SOD、GSH-PX活性,降低血清和肝脏MDA水平,有效减小脂肪细胞直径。其中,青砖茶的效果优于绿茶,10年砖茶优于1年砖茶。结论青砖茶较绿茶更具有减肥降脂、抗氧化作用。     

百姓喝绿茶减肥

菲律宾当地从事健康保健的大夫雷蒙告诉笔者,当地人喜欢吃油炸食品,加之菲律宾蔬菜价格不菲,当地人普遍纤维素摄入不够,因此很多人都有腹部肥胖的烦恼.     

乌龙茶减肥作用机制的研究

目的 :　乌龙茶是否能抑制由于喂饲高脂饲料而引起的肥胖。方法 :　以添加乌龙茶的高脂肪食喂饲小鼠 1 0 w,检查小鼠体重、肝脏重量、脂肪组织重量以及肝中甘油三酯的含量 ;从乌龙茶中分离促进脂肪分解的活性物质并检查在脂肪细胞中对去甲肾上腺素诱导脂肪分解的作用。结果 :　乌龙茶可以抑制喂饲高脂饲料引起的肥胖和脂肪肝。乌龙茶的水提取物能够促进去甲肾上腺素诱导的脂肪分解 ,其活性成分之一经鉴定是咖啡因。咖啡因能增强去甲肾上腺素诱导脂肪细胞中的脂肪分解作用。乌龙茶能抑制胰脂肪酶的活性。结论 :　乌龙茶的减肥作用可能是由于乌龙茶中所含具有促进脂肪分解作用的咖啡因和乌龙茶中其他有抑制脂肪吸收的物质所致。     

读“五种绿茶的瘦身茶方”有感

《东方食疗与保健》(2004年第8期)连载“精心打造今日卫庄公夫人‘肤如凝脂’(连三)”一文中有“五种绿茶的瘦身茶方”一节,读后颇有启迪。“瘦身”,说白了就是“减肥”。关于饮茶能减肥之事,自古以来就受到人们的推崇,在众多古藉中多有记载,如《檐曝日记》记有饮茶“去肥腻”;《老老恒言》亦载:“饭后饮之可解肥浓”;《本草拾遗》明白提出:饮茶可“去人脂”。减肥,包括轻身与健美。肥胖病大都是因人体脂肪代谢失常,过多积累所引起。茶叶的减肥功效是由于茶叶中含有茶多酚、叶绿素、维生素C等多种有效成分的综合作用。现已查明,茶多酚能溶…     

两种减肥食品的减肥效果观察和比较

迄今为止，较为常见的预防和治疗肥胖症的方法有药物疗法、饮食疗法、运动疗法和行为疗法4种，但无论哪种疗法都需要结合低热量饮食。可见，饮食疗法是最根本、安全的减肥疗法。因此，筛选具有减肥作用的保健食品即成为减肥研究过程中的一个重要课题［‘］。本文试就减肥口服液和减肥片的减肥效果进行比较和分析。一、实验材料1．减肥口服液主要原料：乌龙茶、白茅根、冬瓜等；减肥片主要原料：山植、荷叶、白茅根、冬瓜等。2．单纯性肥胖人群的选择：以年龄18～55周岁，体重超过标准体重的20％，非疾病引起的肥胖患者作为受试人群。成年人…     

喝绿茶会不会伤胃

北京刘女士：我老伴肠胃不好,可又特别喜欢喝茶,尤其是绿茶。我听人说,绿茶不像红茶、乌龙茶,常喝会伤胃,是这样吗?他以后该不该喝绿茶呢?     

一种减肥食品的动物试验研究

肥胖与健康的关系越来越受到人们的关注,膳食不平衡及营养过剩是引起肥胖的重要因素,由此所产生的一些慢性代谢性疾病也随之形成,对人民健康造成相当程度的影响。     

低热量饮食的减肥效果

肥胖的发生与热能的摄入密切相关。因此，预防和治疗肥胖必需从饮食着手。我们对５２名肥胖者进行了低热量饮食减肥观察。１肥胖与肥胖度判定应用ＢＦＡ－１００人体脂肪分析仪〔１〕测定人体脂肪含量（Ｆ％），以Ｆ％为判定肥胖与肥胖度的标准。２减肥食谱的编制１北京军...     

Green tea polyphenols and cancer chemoprevention: multiple mechanisms and endpoints for phase II trials

Among the numerous polyphenols isolated from green tea, the catechin EGCG predominates and is the target of anticancer research. But studies suggest that EGCG and other catechins are poorly absorbed and undergo substantial biotransformation to species that include glucuronides, sulfates, and methylated compounds. Numerous studies relate the antioxidant properties of the catechins with anticancer effects, but recent research proposes other mechanisms of action, including those involving methyl transfers that are subject to allelic variability in the enzyme catechol O-methyl transferase. However, preclinical research is promising and EGCG appears to be ready for further study in phase II and III trials.     

Relationship between Regular Green Tea Intake and Osteoporosis in Korean Postmenopausal Women: A Nationwide Study

Mixed results have been reported regarding whether habitual tea intake affects bone health. This study investigated the relationship between green tea intake and bone mineral density (BMD) in postmenopausal Korean women. We used data from the Korean National Health and Nutrition Examination Surveys from 2008 to 2011 and divided the participants into three groups according to their frequency of green tea intake over the past 12 months. BMD of the lumbar spine, total femur, and femur neck was measured using dual-energy X-ray absorptiometry. The odds ratios (ORs) and 95% confidence intervals (CIs) of osteoporosis and osteopenia according to green tea consumption were analyzed. Participants who did not consume green tea or consumed less than one cup per day were more likely to have osteopenia of the lumbar spine or femur than those who consumed it once to three times a day (OR 1.81 and 1.85, 95% CI, 1.20–2.71; and 1.23–2.77). Moreover, ORs for osteoporosis were 1.91 (95% CI 1.13–3.23) and 1.82 (95% CI 1.09–3.05) in non-consumers and consumers who drank less than one cup per day, respectively, compared with the reference group. These results support that green tea consumption may have benefits on bone health.     

绿茶多酚防治老年神经退行性疾病研究进展

老年神经退行性疾病如帕金森病和阿尔茨海默病等均为多病因的复杂性疾病,在临床上单一作用靶点的药物治疗效果有限。绿茶多酚以其清除自由基、鳌合金属离子和调节神经细胞内蛋白激酶通路等作用在老年神经退行性疾病的防治中具有很大的潜力,本文就近年来该方面的研究进展进行阐述。     

Green tea improves metabolic biomarkers,not weight or body composition: a pilot study in overweight breast cancer survivors

Background: Overweight status after breast cancer treatment may increase a woman’s risk for recurrent disease and/or early onset cardiovascular disease. Green tea has been proposed to promote weight loss and favourably modify glucose, insulin and blood lipids. This pilot study tested the effect of daily decaffeinated green tea consumption for 6 months on weight and body composition, select metabolic parameters and lipid profiles in overweight breast cancer survivors. Methods: The effect of daily decaffeinated green tea intake on weight, body composition and changes in resting metabolic rate, energy intake, glucose, insulin, homeostasis model assessment – insulin resistance (HOMA‐IR) and lipids was evaluated in overweight breast cancer survivors. Participants had a mean weight of 80.2 kg; body mass index (BMI) 30.1 kg m^?2; and body fat 46.4%. Participants (n = 54) were randomised to 960 mL of decaffeinated green or placebo tea daily for 6 months. Results: Mean (SD) tea intake among study completers (n = 39) was 5952 (1176) mL week^?1 and was associated with a significant reduction in energy intake (P = 0.02). Change in body weight of ?1.2 kg (green tea) versus +0.2 kg (placebo) suggests a weight change effect, although this was not statistically significant. Decaffeinated green tea intake was associated with elevated high‐density lipoprotein (HDL) levels (P = 0.003) and nonsignificant improvements in the HDL/LDL ratio and HOMA‐IR (?1.1 ± 5.9: green tea; +3.2 ± 7.2: herbal). Conclusions: Intake of decaffeinated green tea for 6 months was associated with a slight reduction in body weight and improved HDL and glucose homeostasis in overweight breast cancer survivors.     

茶及茶中多酚类化合物减肥作用的研究进展

近10年来,肥胖患病率明显增加,已成为现代医学最严重问题之一。据报道,茶儿茶素尤其是绿茶儿茶素具有抗肥胖作用。然而,由于茶的品种各异,萃取条件不同,以致研究结果出现不一致的结论。最新的研究发现,脂肪酸合酶与肥胖相关,而茶多酚对脂肪酸合酶具有可逆和不可逆的双重作用,这可能成为茶及茶中多酚类化合物抗肥胖作用机制研究的新途径。目前,关于茶减肥的机制性研究主要集中在绿茶及绿茶多酚方面。因此,有必要对其他茶及茶多酚减肥作用及机制进行进一步研究。     

Green tea supplementation ameliorates insulin resistance and increases glucose transporter IV content in a fructose-fed rat model

Summary.Background: Sprague-Dawley rats fed a fructose-rich diet exhibit insulin resistance and hypertension, a pathologic status resembling human type II diabetes mellitus, and are an excellent laboratory animal model for research on insulin action and the development of hypertension. Since green tea has numerous beneficial effects, we tested its effect on fructose-fed rats. Aim: The present study was therefore designed to further evaluate the effects of green tea supplementation on insulin resistance, hypertension, and the glucose transporters I and IV contents in adipose tissue in the fructose-fed rat model.Methods: The animals were divided into three groups and fed for 12 weeks with standard chow and water (control group), a high fructose diet and water (fructose group), or the same high fructose diet, but with green tea (0.5 g of lyophilized green tea powder dissolved in 100 mL of deionized distilled water) instead of water (fructose/green tea group). During the 12 weeks study period, fresh water or green tea was provided daily at 6:00 PM. Blood pressure was measured twice a week, and an oral glucose tolerance test performed after 12 weeks of diet supplementation.At the end of the experiment, plasma triglyceride (TG), free fatty acid (FFA), glucose, and insulin were assayed. The epididymal fat pads from all rats in the same group were pooled and adipocytes isolated and tested for insulin binding, glucose uptake, and their content of glucose transporters I (GLUT I) and IV (GLUT IV).Result: Compared to the control group, the fructose group developed fasting hyperglycemia, hyperinsulinemia, and elevated blood pressure. Insulin-stimulated glucose uptake and insulin binding of adipocytes were significantly reduced, and the glucose transporter IV content of adipocytes also decreased. The fructose/green tea group showed improvement in all of these metabolic defects and in insulin resistance and blood pressure.Conclusion: Based on these results, we suggest that the amelioration of insulin resistance by green tea is associated with the increased expression of GLUT IV.     

绿茶多酚对心理应激大鼠行为表现的影响

目的观察绿茶多酚对心理应激大鼠行为、认知行为以及学习和记忆能力的影响。方法将Wistar大鼠随机分为5组:正常对照组(CT)、应激对照组(SCT)和低、中、高剂量GTPs干预应激组(SLG、SMG和SHG)。采用束缚应激3周建立心理应激动物模型。通过旷场实验了解动物的自主探究行为改变,以水迷宫实验检验动物的认知行为,以避暗实验检测动物的学习和记忆能力。分别以放免法、化学荧光法、双抗夹心ELISA法检测血浆皮质醇水平、去甲肾上腺素和多巴胺含量以及IL-6和IL-2水平。结果各应激组动物的血浆皮质醇水平明显升高,SMG组和SHG组血浆皮质醇与CT组相比显著升高,但较SCT组明显降低。与CT组相比,SCT组动物在旷场中的潜伏期延长,其穿格数、直立次数减少;SLG组动物的表现与SCT组相近,而SMG组和SHG组动物只出现穿格数的减少,而且,SMG组和SHG组动物的潜伏期和直立次数与SCT组比较也存在显著性差异。避暗反应结果显示,各应激组动物的潜伏期均明显延长,而电击次数仅在SCT组和SLG组动物出现显著增加。水迷宫测试显示,与CT组比较,SCT组和SLG组动物完成水迷宫所需的时间和发生错误的次数均明显增加。另外,与SCT组相比,SMG组和SHG组动物完成水迷宫所需的时间和错误次数以及避暗反应电击次数均明显降低。各应激组动物在束缚应激后,其血浆IL-6和IL-2水平均明显升高;SCT组和SLG组动物血浆NE和DA水平显著降低,而SMG组和SHG组动物未见显著性变化。与SCT组相比,SMG组和SHG组动物血浆NE和DA水平明显升高,且血浆IL-6含量亦显著增加。结论心理应激引起动物应激激素分泌增加,行为学表现异常,而适量补充GTPs可改善心理应激机体的行为学表现,提高应激机体的自主活动和探究行为、认知功能以及学习、记忆能力。     

Rare earth elements in Oolong tea and their human health risks associated with drinking tea

In this study, the content of rare earth oxides (REOs) in made teas and infusions of 57 Oolong tea samples was investigated because when compared to other teas, Oolong tea is believed to contain a higher amount of REOs. The risks of REOs in Oolong tea to human health arising from drinking tea were assessed. The content of rare earth oxides (∑REOs) in the various types of Oolong tea varied from 0.62 to 10.1 mg/kg, 71.9–79.6% of which consisted of Ce, La, Y, and Nd. One-time infusion and five times successive infusions resulted in leached rates of 9.86–17.4% and 25.8–32.6% of the total REOs, respectively. The leached REOs increased with TOC in tea infusions. The proposed DAI_tea (daily allowable intake, 42 μg) would be exceeded when the content of REOs in Oolong tea was greater than 6.84 mg/kg based on the calculation with the highest consumption rate of Oolong tea (15 g/day) and the highest leached rate (41.0%). Among the tea samples studied, only 1.8% of the samples exhibited an REO content of greater than 6.84 mg/kg. Thus, in general, the intake of REOs by drinking Oolong tea is negligible.     

Effect of Green Tea on Plasma Adiponectin Levels: A Systematic Review and Meta-analysis of Randomized Controlled Clinical Trials

Objective: Our objective was to perform a systematic review and meta-analysis on randomized controlled trials (RCTs) assessing the effect of green tea on serum adiponectin concentration.

Method: We searched PubMed, ISI Web of Science, Scopus, and the Google Scholar databases up to November 2016. RCTs conducted among human adults studied the effects of green tea and green tea extract on serum adiponectin concentrations as an outcome variable was included. The weighted mean differences and standard deviations (SD) of change in serum adiponectin levels were calculated. The random effects model was used for deriving a summary of mean estimates with their corresponding SDs. The protocol was registered with PROSPERO (No. CRD42017057716).

Result: Fourteen RCTs were eligible to be included in the systematic review and the meta-analysis. Our analysis showed that green tea did not significantly affect adiponectin concentrations in comparison with placebo (weighted mean difference = ?0.02 µg/ml, 95% confidence interval [CI], ?0.41, 0.38; p = 0.936). There was a substantial heterogeneity between studies (I² = 91.7%; p < 0.0001). Subgroup analyses based on sex, type of intervention, continent, and body mass index (BMI) could not explain the sources of heterogeneity. Metaregression analyses revealed that the dose and duration of green tea ingestion did not have any effect on adiponectin concentrations.

Conclusion: Green tea could not change the circulatory adiponectin levels. The dose and duration of green tea could not change the result. RCTs with longer follow-up periods and higher doses are needed to replicate our results.