A META-ANALYSIS OF THE EFFECTS OF GREEN TEA COMBINED WITH PHYSICAL ACTIVITY ON BLOOD LIPIDS IN HUMANS

ABSTRACT Introduction: Most studies of green tea extract (GTE) combined with physical activity have reported a preventative effect for cardiovascular disease; however, the findings regarding the effects on serum lipids are controversial. Objective: This meta-analysis aimed to examine the evidence of the effects of GTE combined with physical activity on the serum lipid content in humans. Methods: In June 2017, we conducted electronic searches of PubMed, Web of Science, and Cochrane Library to identify pertinent studies: those with an experiment period exceeding two weeks, human randomized controlled trials (RCTs), and those that only assessed GTE with physical activity were included. A random effects model meta-analysis was used in this review. Results: A total of 271 citations were retrieved in our search of the electronic literature, and 7 RCTs, which included 608 individuals, were identified. Overall, there was no significant decrease in low-density lipoprotein cholesterol (LDL-C) (SMD:-0.169; 95% confidence interval [CI]:-0.414 to 0.076; I2=22.7%; p=0.177) or total cholesterol (TC) levels between the GTE and placebo combined with the physical activity group. Similar results were also observed for high density-lipoprotein cholesterol (HDL-C) and triglycerides (TG). In the subgroup and sensitivity analyses of the five studies, the TC levels of the subjects who received a lower dose of epigallocatechin gallate (EGCG) together with performing physical activity were significantly decreased. Conclusion: Current evidence suggests that green tea combined with physical activity does not improve the lipid and lipoprotein levels in humans. Level of evidence I; Systematic review.

摘要
引言：现有关于绿茶提取物（green tea extract, GTE）联合体力活动的多数研究均报道了其对心血管疾病的预防作用，但有关其对血清脂质影响的研究结论尚存争议。
目的：本荟萃分析旨在探讨绿茶提取物联合体力活动对人体血清脂质含量的影响证据。
方法：2017年6月，我们对PubMed、Web of Science及Cochrane图书馆进行电子检索，筛选符合以下条件的相关研究：实验周期超过2周、针对人体的随机对照试验（randomized controlled trial, RCT），且仅评估绿茶提取物联合体力活动的干预效果。本综述采用随机效应模型开展荟萃分析。
结果：本次电子文献检索共检索到271篇引用文献，最终纳入7项随机对照试验，涉及608名受试者。总体而言，与安慰剂联合体力活动组相比，绿茶提取物联合体力活动组的低密度脂蛋白胆固醇（low-density lipoprotein cholesterol, LDL-C）（标准化均数差（standardized mean difference, SMD）：-0.169；95%置信区间（confidence interval, CI）：-0.414~0.076；I²=22.7%；P=0.177）及总胆固醇（total cholesterol, TC）水平均无显著降低。高密度脂蛋白胆固醇（high-density lipoprotein cholesterol, HDL-C）与甘油三酯（triglycerides, TG）的检测结果也呈现相似趋势。在针对5项研究的亚组分析与敏感性分析中，摄入较低剂量表没食子儿茶素没食子酸酯（epigallocatechin gallate, EGCG）并联合体力活动的受试者，其总胆固醇水平出现显著降低。
结论：现有证据表明，绿茶提取物联合体力活动无法改善人体的脂质及脂蛋白水平。本研究证据等级为I级，属于系统综述。