Drinking tea significantly slashes risk of diabetes — but only if you've had 4 cups

WUHAN, China — If you're worried about developing diabetes, drinking tea throughout the day may help. New research shows that people who consume at least four mugs a day are 17 percent less likely to develop the disease.

Scientists from Wuhan University in China say the findings apply to black, green or oolong varieties. The worldwide project tracked more than a million participants for an average of ten years to reach the conclusion.

Study authors credit compounds known as flavonoids in tea for the benefit. These naturally occurring chemicals mimic antioxidants, destroying harmful free radicals. Lead author Xiaying Li, of Wuhan University of Science and Technology in China describes the results as “exciting.”

“They suggest people can do something as simple as drinking four cups of tea a day to potentially lessen their risk of developing type 2 diabetes,” she says in a statement.

For their research, Li and colleagues pooled data from 19 studies involving 1,076,311 volunteers in eight countries. They report that drinking one to three cups a day lowered diabetes risk by just four percent. Yet people who drank four or more saw that figure rise significantly to 17 percent.

‘Drinking tea beneficial — but only at high doses'

Tea's health benefits are long established. It boosts immunity and can even help fight off cancer, Alzheimer's and cardiovascular disease and diabetes. But its relationship with diabetes has been less clear with previous analyses reporting inconsistent results. The reason could be that quite large intakes are required.

“Our findings suggest drinking tea is beneficial in reducing the risk of Type 2 diabetes, but only at high doses — at least four cups a day,” says Li. “It is possible that particular components in tea, such as polyphenols, may reduce blood glucose levels, but a sufficient amount of these bioactive compounds may be needed to be effective. It may also explain why we did not find an association between tea drinking and Type 2 diabetes in our cohort study, because we did not look at higher tea consumption.”

The phenomenon stands regardless of gender, geography or tea type, suggesting the amount consumed plays a major role rather than any other factor.

“More research needs to be done to determine the exact dosage and mechanisms behind these observations,” adds Li.

In April, tea was hailed as “the world's greatest health drink” at a virtual medical conference in the U.S. Scientists said two to four cups a day reduced the risk of a host of serious illnesses, with more providing few additional bonuses.

Li presented the findings at a meeting of the European Association for the Study of Diabetes in Stockholm, Sweden.

South West News Service writer Mark Waghorn contributed to this report.