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Journal of Nutrition and Metabolism
Volume 2013 (2013), Article ID 765383, 7 pages
http://dx.doi.org/10.1155/2013/765383
Clinical Study

Gynostemma pentaphyllum Tea Improves Insulin Sensitivity in Type 2 Diabetic Patients

1Endocrine and Diabetes Unit, Department of Molecular Medicine and Surgery, Karolinska Institute, Karolinska University Hospital, SE 17176 Stockholm, Sweden
2Hanoi Medical University, Hanoi 1000, Vietnam
3Department of Endocrinology and Diabetes, National Institute of Gerontology, Hanoi 1000, Vietnam
4Department of Internal Medicine, University of Manitoba, Winnipeg, MB, Canada R3T 2N2

Received 10 July 2012; Revised 6 December 2012; Accepted 11 December 2012

Academic Editor: Maurizio Muscaritoli

Copyright © 2013 V. T. T. Huyen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Aims. To evaluate the effect of the traditional Vietnamese herb Gynostemma pentaphyllum tea on insulin sensitivity in drug-naïve type 2 diabetic patients. Methods. Patients received GP or placebo tea 6 g daily for four weeks and vice versa with a 2-week wash-out period. At the end of each period, a somatostatin-insulin-glucose infusion test (SIGIT) was performed to evaluate the insulin sensitivity. Fasting plasma glucose (FPG), , and oral glucose tolerance tests and insulin levels were measured before, during, and after the treatment. Results. FPG and steady-state plasma glucose (SIGIT mean) were lower after GP treatment compared to placebo treatment ( ). The levels of FPG in the control group were slightly reduced to versus  mmol/L in GP group ( ), and the effect on FPG was reversed after exchanging treatments. The glycometabolic improvements were achieved without any major change of circulating insulin levels. There were no changes in lipids, body measurements, blood pressure, and no reported hypoglycemias or acute adverse effects regarding kidney and liver parameters. Conclusion. The results of this study suggested that the GP tea exerted antidiabetic effect by improving insulin sensitivity.