Coffee or tea? Tea – especially black tea – might be a better choice. A mathematical analysis found that the prevalence of type 2 diabetes is low in countries where people drink a lot of black tea. The disease — a chronic, life-threatening condition that reduces the body's ability to turn sugar, or glucose, into energy — is a growing problem around the world. The number of cases is expected to soar to 438 million over the next two decades.

A multinational team of researchers compared sales information for black tea in 50 countries with data from the World Health Organization about a variety of diseases in those same nations. The Irish consumed the most tea – more than two kilograms a year per person – while people in China, Morocco and Mexico drank the least.

The analysis showed a relationship between black tea consumption and rates of diabetes, but not with any other health condition. The authors of the study point out that the link does not imply that one is caused by the other, although they say previous research has indicated the complex flavonoids in black tea have a potential health benefit.

Tea is an ancient drink that is still one of the world's most widely consumed hot beverages.