Green tea, black tea, and epigallocatechin modify body composition, improve glucose tolerance, and differentially alter metabolic gene expression in rats fed a high-fat diet

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Chen, Nora, Bezzina, Rebbeca, Hinch, Eddie, Lewandowski, Paul, Cameron-Smith, David, Mathai, Michael ORCID: 0000-0001-8783-2122, Jois, Mark and Weisinger, Richard (2009) Green tea, black tea, and epigallocatechin modify body composition, improve glucose tolerance, and differentially alter metabolic gene expression in rats fed a high-fat diet. Nutrition Research, 29 (1). pp. 784-793. ISSN 0271-5317

Abstract

The mechanisms of how tea and epigallocatechin-3-gallate (EGCG) lower body fat are not completely understood. This study investigated long-term administration of green tea (GT), black tea (BT), or isolated EGCG (1 mg/kg per day) on body composition, glucose tolerance, and gene expression related to energy metabolism and lipid homeostasis; it was hypothesized that all treatments would improve the indicators of metabolic syndrome. Rats were fed a 15% fat diet for 6 months from 4 weeks of age and were supplied GT, BT, EGCG, or water. GT and BT reduced body fat, whereas GT and EGCG increased lean mass. At 16 weeks GT, BT, and EGCG improved glucose tolerance. In the liver, GT and BT increased the expression of genes involved in fatty acid synthesis (SREBP-1c, FAS, MCD, ACC) and oxidation (PPAR-α, CPT-1, ACO); however, EGCG had no effect. In perirenal fat, genes that mediate adipocyte differentiation were suppressed by GT (Pref-1, C/EBP-β, and PPAR-γ) and BT (C/EBP-β), while decreasing LPL, HSL, and UCP-2 expression; EGCG increased expression of UCP-2 and PPAR-γ genes. Liver triacylglycerol content was unchanged. The results suggest that GT and BT suppressed adipocyte differentiation and fatty acid uptake into adipose tissue, while increasing fat synthesis and oxidation by the liver, without inducing hepatic fat accumulation. In contrast, EGCG increased markers of thermogenesis and differentiation in adipose tissue, while having no effect on liver or muscle tissues at this dose. These results show novel and separate mechanisms by which tea and EGCG may improve glucose tolerance and support a role for these compounds in obesity prevention.

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Additional Information

Online ISSN: 1879-0739

Item type Article
URI https://vuir.vu.edu.au/id/eprint/4222
DOI https://doi.org/10.1016/j.nutres.2009.10.003
Official URL http://dx.doi.org/10.1016/j.nutres.2009.10.003
Subjects Historical > Faculty/School/Research Centre/Department > School of Biomedical and Health Sciences
Historical > FOR Classification > 0606 Physiology
Historical > FOR Classification > 1111 Nutrition and Dietetics
Historical > SEO Classification > 970111 Expanding Knowledge in the Medical and Health Sciences
Keywords ResPubID17995. Green tea, black tea, epigallocatechin, laboratory rats, adipose tissue, gene expression, glucose tolerance tests, body fat, energy metabolism, lipid homeostasis
Citations in Scopus 148 - View on Scopus
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