Drinking at least four cups of any of these teas a day has been linked to a 17% lower risk of developing type 2 diabetes over an average period of 10 years, according to research published on Saturday. The research, which has not yet been published in a scientific journal, will be presented at the annual meeting of the European Association for the Study of Diabetes in Stockholm this week.
The relationship between drinking tea and the risk of type 2 diabetes has been previously studied, but the results have been inconsistent, said Xiaying Li, first author of the research and a graduate student at Wuhan University of Science and Technology in the china
“Our study showed that the association between tea consumption and (type 2 diabetes) depended on the amount of tea consumed. Only sufficient tea consumption can show clinical effects,” Li said by email. “Based on our findings, I would advise the public to consume more tea in their daily lives, if appropriate.”
Initially, the researchers found that tea drinkers and non-drinkers in their study had a similar risk of developing type 2 diabetes.
But when researchers decided to examine whether the amount consumed among tea drinkers made a difference by conducting a systematic review of 19 cohort studies involving more than 1 million adults from eight countries, the results were different: the more cups of green, oolong, or black tea participants drank daily, the lower their risk of developing type 2 diabetes. The measures tracked in these studies were whether participants drank less than one cup of tea per day , one to three cups a day or four or more.)
The authors cautioned that their research does not prove that drinking tea reduces the risk of type 2 diabetes, but it does suggest that drinking tea contributes, according to a press release. They also noted that they relied on participants’ self-reports of their tea consumption and could not rule out the possibility that lifestyle and unmeasured physiological factors may have affected the results.
Experts who did not participate in the research agreed with the authors’ acknowledgment of the shortcomings of the current research.
“It could be that people who drink more tea avoid or drink less often more harmful or equivalent sugary drinks, or that they engage in other health behaviors that lead to a lower risk of type 2 diabetes,” Naveed Sattar, professor of medicine metabolic at the University of Glasgow, he said in a statement.
“The findings should be taken with a very large pinch of salt (or cup of tea),” Kevin McConway, emeritus professor of applied statistics at The Open University in the UK, said in a statement. “The problem with meta-analysis findings is that the devil is always in the detail, and we don’t have the detail. Which studies were included? What was their quality? Which people, from which countries, were studied?”
“The particular components of tea, such as polyphenols, can reduce blood glucose concentration by inhibiting the activity of α-glucosidase and/or inhibiting the activity of other enzymes, but a sufficient amount of the bioactive substance is required to be effective,” Li said. .
The take-home message is that lifestyle choices are important in managing the risk of type 2 diabetes, Duane Mellor, a dietitian and senior lecturer at Aston University in Birmingham, UK, said in a statement. Mellor was not involved in the investigation.