Maron David J, Lu Guo Ping, Cai Nai Sheng, Wu Zong Gui, Li Yue Hua, Chen Hui, Zhu Jian Qiu, Jin Xue Juan, Wouters Bert C, Zhao Jian
Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA.
Arch Intern Med. 2003 Jun 23;163(12):1448-53. doi: 10.1001/archinte.163.12.1448.
Tea consumption has been associated with decreased cardiovascular risk, but potential mechanisms of benefit are ill-defined. While epidemiologic studies suggest that drinking multiple cups of tea per day lowers low-density lipoprotein cholesterol (LDL-C), previous trials of tea drinking and administration of green tea extract have failed to show any impact on lipids and lipoproteins in humans. Our objective was to study the impact of a theaflavin-enriched green tea extract on the lipids and lipoproteins of subjects with mild to moderate hypercholesterolemia.
Double-blind, randomized, placebo-controlled, parallel-group trial set in outpatient clinics in 6 urban hospitals in China. A total of 240 men and women 18 years or older on a low-fat diet with mild to moderate hypercholesterolemia were randomly assigned to receive a daily capsule containing theaflavin-enriched green tea extract (375 mg) or placebo for 12 weeks. Main outcome measures were mean percentage changes in total cholesterol, LDL-C, high-density lipoprotein cholesterol (HDL-C), and triglyceride levels compared with baseline.
After 12 weeks, the mean +/- SEM changes from baseline in total cholesterol, LDL-C, HDL-C, and triglyceride levels were -11.3% +/- 0.9% (P =.01), -16.4% +/- 1.1% (P =.01), 2.3% +/- 2.1% (P =.27), and 2.6% +/- 3.5% (P =.47), respectively, in the tea extract group. The mean levels of total cholesterol, LDL-C, HDL-C, and triglycerides did not change significantly in the placebo group. No significant adverse events were observed.
The theaflavin-enriched green tea extract we studied is an effective adjunct to a low-saturated-fat diet to reduce LDL-C in hypercholesterolemic adults and is well tolerated.
饮茶与心血管疾病风险降低有关，但具体的有益机制尚不明确。虽然流行病学研究表明，每天饮用多杯茶可降低低密度脂蛋白胆固醇（LDL-C）水平，但此前关于饮茶和服用绿茶提取物的试验均未显示对人体脂质和脂蛋白有任何影响。我们的目的是研究富含茶黄素的绿茶提取物对轻至中度高胆固醇血症患者脂质和脂蛋白的影响。
在中国6家城市医院的门诊进行双盲、随机、安慰剂对照、平行组试验。共有240名年龄在18岁及以上、采用低脂饮食且患有轻至中度高胆固醇血症的男性和女性，被随机分配接受每日一粒含富含茶黄素的绿茶提取物（375毫克）的胶囊或安慰剂，为期12周。主要观察指标为与基线相比，总胆固醇、LDL-C、高密度脂蛋白胆固醇（HDL-C）和甘油三酯水平的平均百分比变化。
12周后，茶提取物组总胆固醇、LDL-C、HDL-C和甘油三酯水平相对于基线的平均变化分别为-11.3%±0.9%（P = 0.01）、-16.4%±1.1%（P = 0.01）、2.3%±2.1%（P = 0.27）和2.6%±3.5%（P = 0.47）。安慰剂组总胆固醇、LDL-C、HDL-C和甘油三酯的平均水平无显著变化。未观察到明显不良事件。
我们研究的富含茶黄素的绿茶提取物是低饱和脂肪饮食的有效辅助手段，可降低高胆固醇血症成年人的LDL-C水平，且耐受性良好。
