Type 2 diabetes is less common in countries where consumption of black tea is high, according to British Medical Journal. Although incidence of the disease has increased six-fold worldwide in recent decades, it remains comparably low in Ireland, the United Kingdom, and Turkey, the top three consumers of black tea.
The researchers said various factors have contributed to the rise in Type 2 diabetes. They noted, however, that their findings are consistent with other studies that showed protective effects from black tea on diabetes and obesity.
"Relationships Between Black Tea Consumption and Key Health Indicators in the World: An Ecological Study" by A. Beresniak et al., BMJ Open, 11/8/12