A scientific evaluate and meta-analysis of 19 cohort research involving greater than 1 million adults from eight international locations finds that average consumption of black, inexperienced or Oolong tea is linked to a decrease danger of developing type 2 diabetes.
The findings, being introduced at this 12 months’s European Affiliation for the Examine of Diabetes (EASD) Annual Assembly in Stockholm, Sweden (19-23 Sept), recommend that consuming a minimum of 4 cups of tea a day is related to a 17% decrease danger of T2D over a median interval of 10 years.
Our outcomes are thrilling as a result of they recommend that folks can do one thing so simple as consuming 4 cups of tea a day to doubtlessly reduce their danger of creating sort 2 diabetes.”
Xiaying Li, Lead Creator, Wuhan College of Science and Know-how, China
Whereas it is lengthy been identified that repeatedly consuming tea could also be helpful for well being due to the varied antioxidant, anti-inflammatory and anticarcinogenic compounds tea incorporates, much less clear has been the connection between tea consuming and the danger of T2D. Thus far, revealed cohort research and meta-analyses have reported inconsistent findings.
To handle this uncertainty, researchers carried out a cohort research and a dose-response meta-analysis to raised outline the connection between tea consumption and future T2DM danger.
First, they studied 5,199 adults (2583 males, 2616 girls) with no historical past of T2D (common age 42) from the China Well being and Diet Survey (CHNS), who had been recruited in 1997 and adopted till 2009. The CHNS is a multicentre potential research trying on the economics, sociological points and well being of residents from 9 provinces.
On the outset, members stuffed in a foods and drinks frequency questionnaire and offered data on life-style elements reminiscent of common train, smoking and alcohol consumption. Total, 2,379 (46%) members reported consuming tea, and by the top of the research, 522 (10%) members had developed T2D.
After adjusting for elements which can be identified to be linked with elevated danger of T2D, like age, intercourse, and bodily inactivity, researchers discovered that tea drinkers had an identical danger of creating T2D in comparison with non-drinkers. And the outcomes didn’t change considerably when analysed by age and intercourse, or when members who developed diabetes throughout the first 3 years of follow-up had been excluded.
Within the subsequent step of the research, the researchers did a scientific evaluate of all cohort research investigating tea consuming and the danger of T2D in adults (aged 18 or older) as much as September 2021. Total, 19 cohort research involving 1,076,311 members from eight international locations had been included within the dose-response meta-analysis.
They explored the potential affect of various kinds of tea (inexperienced tea, oolong tea, and black tea), frequency of tea consuming (lower than 1 cup/day, 1-3 cups/day, and 4 or extra cups/day), intercourse (female and male), and the placement of the research (Europe and America, or Asia), on the danger of T2D.
Total, the meta-analysis discovered a linear affiliation between tea consuming and T2D danger, with every cup of tea consumed per day decreasing the danger of creating T2D by round 1%.
When put next with adults who did not drink tea, those that drank 1-3 cups every day lowered their danger of T2D by 4%, whereas those that consumed a minimum of 4 cups every single day lowered their danger by 17%.
The associations had been noticed no matter the kind of tea members drank, whether or not they had been male or feminine, or the place they lived, suggesting that it could be the quantity of tea consumed, moderately than another issue, that performs a significant function.
“Whereas extra analysis must be achieved to find out the precise dosage and mechanisms behind these observations, our findings recommend that consuming tea is useful in decreasing the danger of sort 2 diabetes, however solely at excessive doses (a minimum of 4 cups a day)”, says Li.
She provides, “It’s doable that individual parts in tea, reminiscent of polyphenols, could scale back blood glucose ranges, however a enough quantity of those bioactive compounds could also be wanted to be efficient. It could additionally clarify why we didn’t discover an affiliation between tea consuming and sort 2 diabetes in our cohort research, as a result of we didn’t have a look at larger tea consumption.”
Oolong tea is a standard Chinese language tea that is constituted of the identical plant used to make inexperienced and black teas. The distinction is how the tea is processed-;inexperienced tea will not be allowed to oxidise a lot, black tea is allowed to oxidise till it turns black, and oolong tea is partially oxidised.
Regardless of the vital findings, the authors word that the research is observational and can’t show that consuming tea lowered the danger of T2D, however means that it’s more likely to contribute.
And the researchers level to a number of caveats, together with that they relied on subjective assessments of the portions of tea consumed and so they can not rule out the chance that residual confounding by different life-style and physiological elements could have affected the outcomes.