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Green tea extract egcg has pronounced antidiabetic effect

Posted on Tuesday, 21 February, 2012 by anthony

Green tea extract antidiabetic effectResearchers have found that green tea extract (EGCG) enhanced glucose tolerance in genetically diabetic mice (Ortsater et al., 2012). The researchers compared the effects of dietary supplementation of EGCG (10 g/kg of diet) or rosiglitazone (21 mg/kg of diet) - an antidiabtetic drug that works as an insulin sensitizer that makes cells more responsive to insulin - in 7-week old pre-diabetic mice. Fasting blood glucose levels, body weight and food intake was measured during the treatment.

After 10 weeks the mice treated with either green tea extract had significantly lower fasting blood glucose levels compared with the control group (9.3mM±1.1 vs 14.7mM±1.8). The researchers found that green tea extract appeared to attenuate the death of beta cells - Beta cells store insulin and respond to spikes in blood glucose levels by releasing insulin which controls the level of glucose in the blood. It was suggested that green tea extract appears to exert its antidiabetic activity through a combination of reducing insulin resistance and increasing the glucose-induced insulin secretion via the preservation of functional beta cell mass. The green tea extract was also associated with increases in insulin content and with the preservation of pancreatic islet structure – Islets contain the hormone producing beta cells.

The researchers concluded: “this study demonstrates that a pharmacological dose of the green tea catechin, EGCG, possesses pronounced antidiabetic efficacy in vivo – comparable to the effect seen with rosiglitazone” and that the “total plasma EGCG levels shown to be efficacious in mice and rats can be reached by dietary supplementation of EGCG.” However, it should be noted that the amount of green tea extract used in this study was fairly high, making up 1% of the mice diet.

Summary of the effects of green tea extract

  • Green tea extract enhanced glucose tolerance in pre-diabetic mice
  • It reduced fasting blood glucose levels
  • Reduced insulin resistance and increased glucose-induced insulin secretion
  • Green tea extract appears to preserve functional beta cell mass and islet structure
  • Green tea extract had pronounced antidiabetic effect comparable with rosiglitazone
  • The amount of EGCG used in this study was fairly high making up 1% of the mice diet.


Ortsater H, Grankvist N, Wolfram S, Kuehn N and Sjoholm A (2012) Diet supplementation with green tea extract epigallocatechin gallate prevents progression to glucose intolerance in db/db mice. Nutrition & Metabolism 2012, 9:11

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