G.J. van Woudenbergh of InterAct Consortium and colleagues found the possible protective effect after meta-analyzing data from 340,234 participants who were enrolled in the EPIC-InterAct case-cohort study and followed up during 3.99 million person-years during which 12,403 incident type 2 diabetes were identified.
Tea consumption was correlated inversely with incidence of type 2 diabetes. Those who drank four cups of tea per day or more were 16 percent less likely to be diagnosed with type 2 diabetes, compared with non-drinkers.
It was also found that those drinking less than 4 cups of tea per day was associated with 7 percent reduced risk of type 2 diabetes mellitus, compared with those who did not drink any.
The researchers concluded, "A linear inverse association was observed between tea consumption and incidence of type 2 diabetes. People who drink at least 4 cups of tea per day may have a 16% lower risk of developing type 2 diabetes than non-non tea drinkers."
Drinking green tea has been associated with reduced risk of obesity in early studies among other benefits.
PLoS One, Sept. 2012