绿茶的功效与作用（经常喝绿茶有什么好处）
之前写了咖啡的种种益处，有小伙伴反应对咖啡因敏感、眼压高、心悸等等原因不能享受；我建议改喝绿茶并承诺了会补一篇关于绿茶好处的文章：当当当当，虽迟但到。
作为每周要出两天肝病门诊的医生，我关注绿茶对健康的帮助，源于看到日本发表了很多篇绿茶对肝脏有保护的论文；好奇之下，以Gereen tea为关键词查到了多篇文章，发现对绿茶的研究不仅限于日本，绿茶的益处也不限于肝脏。（文章主要结论来源一篇综述，证据级别比较高）。
先说结论：
一.在10项研究中，有8项得出了统计上显著的结果，表明绿茶对肝脏疾病具有保护作用，有两项研究显示了部分（保护肝脏的）倾向,四项研究表明绿茶摄入量与肝病减轻呈正相关;
Among 10 studies, eight yielded statistically significant results showing a protective role of green tea against liver disease but two studies only showed a partial tendency;Also, four studies showed a positive association between green tea intake and attenuation of liver disease
二.绿茶的保护，对脂肪肝及肝脏损害比肝癌更有效；
When considering the protective effects of green tea against subgroups of liver diseases, it seems that they are more effective in fatty liver disease and liver disorders than in liver cancer as two studies involving liver cancer did not show statistical protective effect.
三：绿茶在对抗多种疾病如癌症、肥胖、糖尿病、心血管疾病和神经退行性疾病发挥益处；
Green tea has been shown to have beneficial effects against a variety of diseases such as cancer, obesity, diabetes, cardiovascular disease, and neurodegenerative diseases.
四：也有观察性研究显示茶不能降低血压。
关于饮茶安全剂量：每天不宜饮用太多，过多增加肝损风险，但具体安全饮用量，没找到确定数量，有个图可以参考：0-10杯之内）
茶利于健康的有效成分：绿茶儿茶素
green tea catechins；表没食子儿茶素没食子酸酯
EGCG等，具有抗氧化，降低炎症因子表达的作用。
研究表明其中EGCG还能显著改善痤疮、对抗压力、降低老年痴呆风险等。（赶紧喝几壶压压惊喜）
EGCG significantly improved acne in an 8-week randomized, split-face clinical trial, and was well
tolerated.
最后：延伸一下不同种类茶的比较：研究认为：在绿茶、红茶、白茶和乌龙茶中，乌龙茶降低体重最明显。（小白鼠实验）。
参考文献：
[1] Jin X , Zheng R H , Li Y M . Green tea consumption and liver disease: a systematic review[J]. Liver International, 2010, 28(7):990-996.
[2] D Taubert, Roesen R , E Schömig. Effect of cocoa and tea intake on blood pressure: a meta-analysis.[J]. Archives of Internal Medicine, 2007, 167(7):626-34.
[3] Nakamura Y , Isemura M , Monira P , et al. Anti-inflammatory Action of Green Tea[J]. Anti-Infective Agents in Medicinal Chemistry (Formerly ???Current Medicinal, 2016, 15(2):-.
[4] Lsms A , Hxms A , Jy A , et al. Comparative effect of black, green, oolong, and white tea intake on weight gain and bile acid metabolism[J]. Nutrition, 2019, 65:208-215.