The risk of developing type-1 diabetes was reduced by about 40 percent in rodents genetically modified to develop diabetes, with the potential benefits linked to a potential anti-inflammatory action, according to findings published in the British Journal of Nutrition.
“We provide evidence for the first time that dietary intake of EGCG can delay the development of type-1 diabetes in non-obese diabetic (NOD) mice,” write researchers from Virginia Polytechnic Institute and State University.
“However, further studies are needed to elucidate the mechanism for this EGCG action, which will provide valuable information for clinical trial to further evaluate its anti-diabetic potential in humans with type-1 diabetes,” they added.
Type-1 diabetes occurs when people are not able to produce any insulin after the cells in the pancreas have been damaged, thought to be an autoimmune response. The disease is most common among people of European descent, with around two million Europeans and North Americans affected.
In addition, the incidence of the disease is on the rise at about three per cent per year, according to a meta-analysis in the Archives of Disease in Childhood (doi:10.1136/adc.2007.128579). The number of new cases is estimated to rise 40 per cent between 2000 and 2010.
Study details
The compounds thought to contribute to the health-promoting effects ascribed to green tea are polyphenolic compounds called catechins, which have been the focus of many previous studies on green tea, due to their anti-oxidative properties and their potential role in preventing cancer and cardiovascular disease.
But some research has also suggested a possible link between green tea consumption and diabetes risk, reporting that tea drinking could bring modest benefits for glucose homeostasis and insulin sensitivity.
The new study used mice which spontaneously develop type-1 diabetes. The animals were divided into two groups: One group was fed the control diet, while the second was fed a control diet, while the second group had a supplemental dose of EGCG in their drinking water (0.05 percent)
When the animals reached 32 weeks of age, the researchers report that 67 percent of the animals in the control group had become diabetic (eight out of 12 animals), while diabetes affected only 25 percent of the mice in the EGCG group (three out of 12).
The Virginia-based scientists also report that EGCG- supplemented mice consistently had higher insulin levels and survival rates than the control animals. An elevation in the levels of anti-inflammatory compounds was also observed in the EGCG animals.
“This protective effect is probably due to the preservation of functional b-cell mass. In line with this finding, EGCG also exerts a cytoprotective effect on human pancreatic islets exposed to the inflammatory milieu relevant to type-1 diabetes,” added the researchers. .
Source: British Journal of Nutrition
Published online ahead of print, FirstView Articles, doi: 10.1017/S0007114510004824
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Authors: Z. Fu, W. Zhen, J. Yuskavage, D. Liu