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Original Investigation
June 23, 2003

Cholesterol-Lowering Effect of a Theaflavin-Enriched Green Tea Extract: A Randomized Controlled Trial

Author Affiliations

From the Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tenn (Dr Maron); Rui Jin Hospital, Shanghai, China (Dr Lu); Zhong Shan Hospital, Shanghai (Dr Cai and Ms Jin); Chang Zheng Hospital, Shanghai (Dr Wu); Xin Hua Hospital, Shanghai (Dr Li); Heart and Lung Hospital, Shanghai (Dr Chen); First Hospital, Wuxi, China (Dr Zhu); Nashai Biotech LLC, Nashville (Mr Wouters and Dr Zhao). Dr Maron is a consultant to Nashai Biotech, LLC. Mr Wouters was a Vice President of Nashai Biotech, LLC, when this study was conducted. Dr Zhao is the Chief Science Officer of Nashai Biotech, LLC. Drs Lu and Ms Jin received grants from Kebao Biotechnology Co, Ltd, Shanghai.

Arch Intern Med. 2003;163(12):1448-1453. doi:10.1001/archinte.163.12.1448

Background  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.

Methods  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.

Results  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.

Conclusion  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.