University of Dundee University of Dundee
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2 March 2008

Time for tea: a source of future diabetes therapies?

Scientists working at the University of Dundee have identified new potentially therapeutic properties in an unexpected place: black tea.

While green tea has long been held by many to possess various beneficial effects for our health the same has not been true of it’s counterpart, but now a team led by Dr Graham Rena at Dundee, Scotland, has found that it may have the potential to help combat type 2 diabetes.

Dr Rena and his team, based in the University’s Neurosciences Institute, are interested in identifying agents capable of substituting for insulin in type 2 diabetes, the form of diabetes where the body stops responding to insulin properly.

In collaboration with colleagues at the Scottish Crop Research Institute the researchers discovered that several black tea constituents, known as theaflavins and thearubigins, mimicked insulin action.

"What we have found is that these constituents can mimic insulin action on proteins known as FOXOs," said Dr Rena.

"FOXOs have previously been shown to underlie associations between diet and health in a wide variety of organisms including mice, worms and fruit flies. The task now is to see whether we can translate these findings into something useful for human health."

"Our study is just the first step. If we can identify substances that restore FOXO regulation in people with type 2 diabetes, we might be able to use these to reduce the considerable burden of serious health problems associated with this diagnosis."

"This is something that needs further research and people shouldn’t be rushing to drink masses of black tea thinking it will cure them of diabetes - we are still some way from this leading to new treatments or dietary advice. Our research into tea compounds is at a preclinical, experimental stage and people with diabetes should continue to take their medicines as directed by their doctor."

"However, there is definitely something interesting in the way these naturally occurring components of black tea may have a beneficial effect, both in terms of diabetes and our wider health."

The results of the research appear in the current issue of the journal Aging Cell.

Dr Rena now hopes to secure additional funding for his research to determine more precisely how the tea components mimic insulin action and whether the agents identified in their test-tube studies so far are capable of eliciting similar effects in the clinic.


Diabetes is understood to be the fastest growing epidemic in the developed world. In Tayside the latest figures showed a 90% increase in the incidence of diabetes in the last 9 years. The World Health Organisation estimates that more than 350 million people worldwide will suffer from the disease by 2030. The scale of the problem was also recently recognised in a general resolution by the United Nations and new treatments to alleviate diabetes are urgently required.

Dr Rena’s research has been funded by the Caledonian Research Foundation, the Chief Scientist's Office, Medical Research Council and Tenovus Scotland, plus some additional charitable trust funding.

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