Compared to people who don’t drink tea, those who did reduced their chances of becoming a type 2 diabetic by at least 28 per cent.
It also reduced the risk of developing prediabetes by 15 per cent.
The study included 1,923 adults aged 20-80 living across eight provinces in China.
The beverage increases glucose excretion in urine, improving insulin resistance and therefore better control of blood sugar.
The researchers, from the University of Adelaide in Australia and Southeast University in China, found that dark tea, a type not widely available in the UK, reduced the risk by nearly half (47 per cent).
The effects are also present to a lesser extent in other teas but the team found that the beneficial effects on metabolic control may lie in the unique way dark tea is produced.
This involves microbial fermentation, a process that may yield unique bioactive compounds.
They all exhibit potent antioxidant and anti-inflammatory effects, improve both insulin sensitivity and the performance of beta cells in the pancreas, and change the composition of the bacteria in the gut.
One in every 16 people in the UK has diabetes, the majority with type 2, caused by unhealthy lifestyles. The authors cautioned that the observational study findings cannot prove that drinking tea every day improves blood sugar control, but suggest it is likely to contribute.
The study, reported in the journal Diabetologia, was presented in Hamburg at a meeting of The European Association for the Study of Diabetes.
Also presented were findings by Maccabi Health Services in Israel which said weight-loss jabs can help people with type 2 diabetes control their blood sugar in the long-term.
Semaglutide, sold under the brand names Wegovy, Ozempic and Rybelsus, tackle obesity, but can also “significantly” improve blood sugar control and weight loss in diabetics for up to three years, it said.
In June Prime Minister Rishi Sunak launched a £40million pilot to expand the use of weight-loss jabs in a bid to tackle obesity.
