The potentially therapeutic properties in black tea have been discovered by scientists at the University of Dundee.
Green tea has long been held to possess various health benefits.
Dr. Graham Rena, of the university's Neurosciences Institute, said his team's research into tea compounds is at a pre-clinical, experimental stage.
However, he said, "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."
However, people with diabetes should continue to take their medicines as directed by their doctor, Rena stressed.
He added, "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."
Rena's team 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.
They have discovered that several black tea constituents, known as theaflavins and thearubigins, mimic insulin action.
"What we have found is that these constituents can mimic insulin action on proteins known as FOXOs," said 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."
The results of the research appear in the current issue of the journal Aging Cell.
Rena now hopes to secure additional funding for his research to determine more precisely how the tea components mimic insulin action.
From the March 3, 2008, Prepared Foods e-Flash