A daily cup of dark tea may help maintain healthy blood sugar levels and reduce the risk of developing diabetes, a new study suggests.
For the study, researchers looked at 1,923 adults in China who either didn’t drink tea at all or who drank only one type of tea, such as green tea, black tea, or a beverage known as dark tea – which, unlike other types of tea, is microbially fermented during processing – and looked at data on diabetes diagnoses, blood sugar levels, and lab tests that show how well the body can process sugar.
Overall, people who drank tea daily were 28 percent less likely to have diabetes than participants who didn’t drink tea at all, according to the study, which was presented at the annual meeting of the European Association for the Study of Diabetes (EASD) in Hamburg, Germany. Daily tea drinkers were also 15 percent less likely to have prediabetes, a condition that develops when blood glucose levels are slightly elevated but not high enough to diagnose as full-blown diabetes.
The study wasn’t a controlled experiment designed to prove whether or how drinking tea in general, or dark tea in particular, might directly affect blood sugar levels or diabetes risk. It’s also unclear whether the results from a population in China, where tea consumption is commonplace, would apply to people from other countries where tea isn’t as popular, or to people from other racial or ethnic groups.
Still, says Erin Palinski-Wade, RD, CDCES, a registered dietitian who works with people with diabetes and was not involved in the new study, the study adds to an already large body of evidence linking tea consumption, including dark tea, to a lower risk of type 2 diabetes.
Many teas are rich in antioxidants, which may help reduce inflammation, a condition that’s been linked to the development of type 2 diabetes, Palinski-Wade says. Findings from the new study and other research suggest that a variety of teas, including green and black in addition to dark tea, offer health benefits, Palinski-Wade says. “This is especially true when [unsweetened] tea is substituted for sugary beverages such as soda and flavored coffee drinks.”