It has long been thought that the answer to many of life’s problems is a good cup of tea.
Now a major study has found that four cups a day could also slash the risk of type two diabetes.
The research on more than 1 million people found that plenty of tea cuts the risk of the condition by almost one fifth.
Scientists said the findings, presented at the European Association for the Study of Diabetes annual meeting in Stockholm, were “exciting” – showing the simple steps people can take to protect their health.
Around 5 million people in the UK have diabetes, with nine in 10 cases type two.
The systematic review and meta-analysis of 19 cohort studies examined the impact of tea-drinking in eight countries, with black, green and Oolong teas varieties under examination.
Regardless of the type of tea consumed, four cups a day was linked to a 17 per cent lower risk of developing type two diabetes over a decade.
Oolong tea is a traditional Chinese tea that’s made from the same plant used to make green and black teas.
The differences in the tea relate to how it is processed.
Green tea is not allowed to oxidise much, black tea – the most common type of brew drunk in the UK – is allowed to oxidise until it turns black, and Oolong tea is partially oxidised.
The international research, led by scientists from China, did not examine any impact from adding milk to tea. However, separate research suggests moderate amounts of dairy can also protect against diabetes.
It has long been known that tea may be beneficial for health because of the various antioxidants, anti-inflammatory and anticarcinogenic compounds it contains.
But the link with diabetes has been less clear, with previous studies proving inconsistent.
The new research is observational, meaning it could not prove that the tea was the cause of the lower risk.
But the size of the study has added to confidence that a regular cup of tea could help to cut the risk of diabetes.
Lead author Xiaying Li from Wuhan University of Science and Technology, said: “Our results are exciting because they suggest that people can do something as simple as drinking four cups of tea a day to potentially lessen their risk of developing type 2 diabetes”.
Researchers carried out a systematic review of all cohort studies investigating tea drinking and the risk of type two diabetes in adults up to September 2021. Overall, 19 cohort studies involving 1,076,311 participants from eight countries were included.
Those who drank between one and three cups a day lowered their risk of diabetes by just four per cent. But drinking at least four cups a day saw a risk reduction of 17 per cent.
Scientists said the associations were observed regardless of the type of tea participants drank, whether they were male or female, or where they lived, suggesting that it may be the amount of tea consumed, rather than any other factor, that plays a major role.
“While more research needs to be done to determine the exact dosage and mechanisms behind these observations, our findings suggest that drinking tea is beneficial in reducing the risk of type 2 diabetes, but only at high doses (at least 4 cups a day)”, said Li.
She added: “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.”
Other experts said it was possible that any apparent health gain from drinking tea actually occurred because people drank it instead of less healthy options.
Prof Naveed Sattar, Professor of Metabolic Medicine, University of Glasgow, said: “Given the nature of this study, it cannot prove tea prevents diabetes per se. Rather it could be that people who drink more tea avoid or less often drink more harmful sugary drinks or equivalent or that they have other health behaviours that leads them to have lower risks of type 2 diabetes.
“There is no good trial evidence whatsoever that the chemicals in tea prevent diabetes, so I suspect its more about tea being healthier (less calorific) than many alternative drinks or tea drinkers leading healthier lives more generally.”