Drink more tea to reduce your risk of developing type 2 diabetes

According to a systematic review and meta-analysis of studies including more than one million people, four or more cups of black, green or oolong tea each day is linked to a 17% lower risk of developing type 2 diabetes.

Drinking a lot of tea can reduce the risk of developing type 2 diabetes, a study of more than a million adults finds.

Four or more cups of black, green or oolong tea each day is linked to a 17% lower risk of developing type 2 diabetes.

Moderate consumption of black, green or oolong tea is linked to a lower risk of developing type 2 diabetes (T2D), according to the results of a systematic review and meta-analysis of 19 cohort studies with more than 1 million adults from eight countries. .

The results suggest that drinking at least four cups of tea a day is associated with a 17% lower risk of T2D over an average period of 10 years. The study will be presented at this year’s European Association for the Study of Diabetes (EASD) annual meeting in Stockholm, Sweden (September 19-23).

“Our results are exciting because they suggest that people can do something as simple as drinking four cups of tea a day to potentially reduce their risk of developing type 2 diabetes,” says lead author Xiaying Li of the University of Science and Technology Technology from Wuhan in China.

Tea contains several antioxidant, anti-inflammatory and anti-cancer compounds. Although it has long been known that drinking tea regularly can be beneficial to health due to these properties, the relationship between tea consumption and T2D risk is less clear. Cohort studies and meta-analyses published to date have reported inconsistent findings.

To address this uncertainty, researchers conducted a cohort study and dose-response meta-analysis to better define the relationship between tea consumption and future risk of T2D.

Lemon and cinnamon tea

Compared to adults who did not drink tea, those who drank 1-3 cups a day reduced their risk of T2D by 4%. More impressively, those who consumed at least 4 cups daily reduced their risk by 17%.

First, they studied 5,199 adults (2,583 men, 2,616 women) with a mean age of 42 years and no history of T2D from the China Health and Nutrition Survey (CHNS), who were recruited in 1997 and followed until 2009. The CHNS is a multicentre. prospective study analyzing the economy, sociological problems and health of residents of nine provinces.

At baseline, participants completed a food and beverage frequency questionnaire. They also provided information on lifestyle factors such as regular exercise, smoking and alcohol consumption. In total, 2,379 (46%) participants reported drinking tea. By the end of the study, 522 (10%) participants had developed T2D.

The researchers found that tea drinkers had a similar risk of developing T2D compared to non-drinkers after adjusting for factors known to be associated with an increased risk of T2D, such as age, sex and physical inactivity. Furthermore, the results did not change significantly when analyzed by age and sex, or when participants who developed diabetes during the first 3 years of follow-up were excluded.

In the next step of the study, the scientists conducted a systematic review of all cohort studies investigating tea consumption and T2D risk in adults (aged 18 years and older) up to September 2021. In total , 19 cohort studies included 1,076,311 participants from eight countries. (China, USA, Finland, Japan, UK, Singapore, Netherlands and France) were included in the dose-response meta-analysis.

They explored the potential impact on T2D risk of different types of tea (green tea, oolong tea and black tea), frequency of tea consumption (less than 1 cup/day, 1-3 cups/day and 4 or more). cups/day), gender (male and female) and study location (Europe and America or Asia).

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

Compared to adults who did not drink tea, those who drank 1-3 cups daily reduced their risk of T2D by 4%. More impressively, those who consumed at least 4 cups each day reduced their risk by 17%.

The associations held regardless of the type of tea the participants drank, whether they were male or female, or where they lived. This suggests that it may be the amount of tea consumed, rather than any other factor, that plays an important role.

“Although more research is needed to determine the dosage and exact mechanisms behind these observations, our results suggest that drinking tea is beneficial in reducing the risk of type 2 diabetes, but only at high doses (at least 4 cups per day)”. , says Li.

He adds: “It is possible that particular components of tea, such as polyphenols, can lower blood glucose levels, but it may take sufficient amounts of these bioactive compounds to be effective. It may also explain why we did not find a association between tea consumption and type 2 diabetes in our cohort study, because we did not look at higher tea consumption.”

Oolong tea is a traditional Chinese tea that is made from the same plant used to make green and black teas. The difference is how the tea is processed: green tea is not oxidized much, black tea is oxidized until it turns black, and oolong tea is partially oxidized.

Despite the important findings, the authors point out that the study is observational. Therefore, drinking tea cannot be proven to be the cause of the reduced risk of T2D, although it does suggest that it is a likely contributor.

In addition, the research team notes several caveats, including that they were based on subjective assessments of the amounts of tea consumed and cannot rule out the possibility that residual confounding by other physiological and lifestyle factors may have affected the results.

The study was funded by the Young Talents Project of the Hubei Provincial Health Commission, China; Key Science and Technology Research Project of the Education Department of Hubei Province, China; Sanuo Diabetes Charity Foundation, China; and Xiangyang Science and Technology Plan Project, China.

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