EGCG from Green Tea helps reduce inflammation in obese subjects by regulating their immune system

March 04, 2010

     Scientists at the Department of Pathology and Laboratory Medicine, University of California, Davis, Medical Center in Sacramento state that obesity predisposes you to an increased incidence of diabetes and CVD. Also, obesity is a pro-inflammatory state. Regulatory T cells (Tregs) are essential for regulating inflammation and are down-regulated (inhibited from acting) in pro-inflammatory states. Animal models of obesity are associated with decreased Tregs. Therefore the dietary modulation of Tregs could be used as a therapeutic strategy to control inflammation.
     Epigallocatechin gallate (EGCG) is a potent anti-inflammatory agent and an active ingredient of Green Tea and is suggested to have a role as a preventive agent in obesity, diabetes and CVD. The role of EGCG in the modulation of Tregs has, however, not been studied. Thus, the aim of the present study was to determine the effect of EGCG on the number and function of Tregs in obese and lean human subjects in vitro, and to delineate its specific regulation mechanisms.
     Tregs were isolated from normal-weight and obese subjects. Tregs were cultured in the absence or presence of EGCG for 24 h. Obese subjects had lower Tregs and IL-10 (a chemical messenger that helps regulate immunity) production than lean subjects. EGCG treatment significantly enhanced the number of Tregs and IL-10 production in vitro in both groups. Also, EGCG decreased NF-kappaB (a messenger strongly connected to inflammation) in Tregs in both groups. Thus, in part, EGCG enhances the functionality of Tregs, i.e. IL-10 production and number by suppressing the NF-kappaB signaling pathway via inducing changes in the activity of genes. The study is published online ahead of print in the February 23rd, 2010 edition of the British Journal of Nutrition.