Rates of type 2 diabetes are lower in countries where many people drink black tea, a finding that supports previous research suggesting that regular consumption of black tea is associated with a reduced risk of diabetes, according to a new study.
Researchers Ariel Beresniak of Data Mining International, in Geneva, Switzerland, and colleagues looked at black tea consumption in 50 countries on every continent in 2009 and compared that to rates of diabetes and cancer, as well as respiratory, infectious and cardiovascular diseases in those nations.
Ireland had the highest level of black tea consumption (more than 4.4 pounds a year per person), closely followed by the United Kingdom and Turkey. Nations with the lowest levels of black tea consumption were South Korea, Brazil, China, Morocco and Mexico.
Statistical analyses showed that diabetes rates were low in countries with high levels of black tea consumption. There was no association between black tea consumption and any of the other health conditions included in the study, according to a journal news release.
The researchers wrote, "These original study results are consistent with previous biological, physiological and ecological studies conducted on the potential of black tea on diabetes and obesity," and provide "valuable additional scientific information at the global level."
Black tea contains a number of complex flavonoids that have been linked with several potential health benefits, the researchers noted. The brewing process releases these flavonoids.
While the study found a mathematical association between black tea consumption and type 2 diabetes rates, it did not prove a cause-and-effect relationship.
BMJ Open, news release, Nov. 7, 2012