A study of more than 1 million adults found that drinking more tea may reduce the risk of developing type 2 diabetes

A systematic review and meta-analysis of 19 cohort studies involving more than 1 million adults in eight countries found that moderate consumption of black, green or oolong tea was associated

The findings, presented this year at the European Association for the Study of Diabetes (EASD) annual meeting in Stockholm, Sweden, suggest that drinking at least four cups of tea a day can reduce the risk of developing T2D by 17% over an average period of

"Our findings are exciting because they show that people can do simple things like drink four cups of tea a day to potentially reduce the risk of developing type 2 diabetes," said

While it has long been known that regular tea drinking may have health benefits because tea contains a variety of antioxidant, anti-inflammatory, and anti-cancer compounds, the relationship between tea drinking and T2D risk is less clear

To address this uncertainty, the researchers conducted a cohort study and dose-response meta-analysis to better define the relationship between

First, they recruited 5,199 adults (2,583 males and 2,616 females) with no history of T2D (mean age 42 years) from the 1997 China Health and Nutrition Survey (CHNS) and followed them through 2009

Initially, participants filled out a diet frequency questionnaire and provided information about lifestyle factors such as regular exercise, smoking, and alcohol consumption

After adjusting for factors known to be associated with an increased risk of T2D, such as age, gender and lack of exercise, the researchers found that people who drank tea had a similar

As a next step in the study, the researchers conducted a systematic review of all cohort studies surveying the risk of T2D in tea drinking and adults (18 years of age or older) as of September 2021

They explored the potential effects

Overall, meta-analyses found a linear association between tea drinking and T2D risk, with each cup of tea per day reducing the risk of developing T2D by about 1%.

People who drank 1-3 cups of tea a day had a 4% lower risk of developing T2D compared to adults who did not drink tea, while those who drank at least 4 cups of tea per day had a 17%

Regardless of what kind of tea the participants drank, whether they were male or female, and regardless of where they lived, these associations were observed, suggesting that perhaps the amount of tea drunk, rather than any other factor, played a major role

"While more research needs to be done to determine the exact dosage and mechanism behind these observations, our findings suggest that drinking tea helps reduce the risk of developing type 2 diabetes, but only in high doses (at least 4 cups per day)," Li said

She added: "Special ingredients in tea, such as polyphenols, may lower blood sugar levels, but a sufficient amount of these bioactive compounds may be needed to be effective

Oolong tea is a traditional Chinese tea that is made with the same plants as green tea and black tea

Despite these important findings, the authors note that the study was observational and does not prove that drinking tea reduces the risk of T2D, but suggests that drinking tea may have a role
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The researchers point to several points to note, including that they rely on subjective assessments of tea consumption, and they can't rule out that residual confusion of other lifestyle and physiological factors may have affected the results
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