The suggestion that drinking tea could protect people from type 2 diabetes was cautioned by many experts ahead of the annual meeting of the European Association for the Study of Diabetes.
The claim is that people who drink four or more cups of tea each day – especially green, oolong or black tea – are 17 percent less likely to develop type 2 diabetes than non-tea drinkers. Drinking a few cups of tea a day has shown no benefit.
“Our results are interesting because they suggest that people can do something as simple as drinking four cups of tea a day to reduce their risk of developing type 2 diabetes,” said Xiaying Li of Wuhan University of Science and Technology. At the official EASD press conference.
“Certain compounds in tea, such as polyphenols, may lower blood glucose levels, but sufficient amounts of these bioactive compounds may be required to be effective,” added Dr. Lee.
“The words ‘opinion’ and ‘potential’ are critical here,” he said. Kevin McConway, PhD, MSc, MBAEmeritus Professor of Applied Statistics at The Open University, Dr Lee said in a separate statement to the excited press.
“Drinking tea will only help reduce diabetes risk if drinking tea reduces risk, that is, if the risk is reduced if you drink tea versus not drinking tea – and this study simply cannot show that. It does or it doesn’t,” Dr Conway emphasized.
Naveed Sattar, FMedSci FRCPath FRCPGlas FRSEProfessor of Metabolic Medicine at the University of Glasgow was also cautiously critical. “There is no good experimental evidence that the chemicals in tea prevent diabetes,” he noted separately.
“So I speculate that tea is healthier (less calorific) than many alternative beverages or that tea drinkers generally lead a healthier lifestyle.”
Dr. Sattar added that tea drinkers may have a lower risk of developing type 2 diabetes because they avoid drinking more harmful sugary drinks and engage in other healthy behaviors.
Dr. Lee will present the findings of two analyzes at the EASD meeting on September 21: the first large observational cohort study and the second an updated systematic review and meta-analysis.
For the cohort study, Dr. Lee and her colleagues collected data on more than 5,100 adults with long-term and ongoing follow-up. Chinese Health and Nutrition Research (CHNS) data on tea drinking behavior were taken from questionnaires filled out two times – 1997 and 2009 – and determined whether people had type 2 diabetes according to the criteria of the American Diabetes Association.
Almost half, 45.8%, were found to be tea drinkers, and 10% of the sampled population had type 2 diabetes. No association was found between tea drinking and the development of type 2 diabetes, however, the hazard ratio between tea drinkers and non-tea drinkers was firmly set at 1.02. Moreover, a sensitivity analysis excluding participants who developed type 2 diabetes during the first 3 years of follow-up did not change the results.
Things were a little different when Dr. Li and colleagues conducted their meta-analysis, which included analyzing data on more than 1 million participants in 19 studies in eight countries published through September 2021.
Here, you find something important (P < .003) The direct relationship between tea consumption and type 2 diabetes, the risk of developing type 2 diabetes was 0.986 for more tea drunk.
The HRs for developing type 2 diabetes in tea drinkers and non-tea drinkers were 1.00 for those who drank less than one cup per day, 0.96 for those with one to two cups, and 0.84 for those who drank four or more cups.
“Further research is needed to determine the exact amount and mechanisms behind these observations. Our findings suggest that drinking tea is beneficial in reducing the risk of type 2 diabetes, but only in large amounts (at least 4 cups per day).” ” said Dr. Lee.
Perhaps, she added, “we did not find an association between tea consumption and type 2 diabetes in our cohort study because we did not observe high tea consumption.”
The temperature in the teacup
“This is big, observational data. It’s not a randomized trial, so there’s a lot of room for misinterpretation of data,” he cautioned. Matt Sydes, MScProfessor of Clinical Trials and Methodology at the MRC Clinical Trials Unit, University College London.
“Everybody drinks fluids. If there’s an effect here (and it’s big), it might be about what you’re not drinking, not the tea you’re drinking. One can’t say at this point. It seems unlikely. A large randomized controlled trial would be needed to confirm that,” Dr. Sides added.
“It is difficult to assess the quality of this research as it is only a conference abstract.” Baptiste Laurent, Ph.DA medical statistician working at University College London also said. They noted that not only observational cohort studies, but all other studies were included in the meta-analysis.
“Therefore, no cause-and-effect conclusions can be drawn. The association may simply be due to other factors, for example, people who drink more tea have a healthier lifestyle. The authors do not seem to have tried to control for confounding, which is often difficult. In a meta-analysis, “Dr. Laurent They said.
Jonathan Cook of the Center for Medical Statistics at the University of Oxford (England) said: “There is reason to be a little skeptical at this point; “We need to have full details to assess it properly,” he said. “It’s a fair attempt to look at it, but it’s not a cut. [using] Proper standard approaches.”
Similar studies have shown that the risk associated with drinking coffee is reduced Duane Mellor, Ph.DRegistered Dietitian and Senior Teaching Fellow at Aston University in Birmingham.
“The important take-home message is that lifestyle is important for controlling the risk of type 2 diabetes,” Dr. Mellor said.
“This includes choosing low-calorie beverages, mainly water, as well as unsweetened tea and coffee as your beverage of choice as part of a healthy lifestyle.”
The research was funded by the Young Talent Project of Hubei Provincial Health Commission, the Education Department of Hubei Provincial Science and Technology Research Key Project, the Sanuo Diabetes Charity and the Xiangyang Science and Technology Planning Project, all in China. Dr. Lee had no conflicts of interest to disclose. Dr. McConway is a trustee and on the Science Media Center Advisory Committee. Dr. Sattar has consulted for many companies making diabetes and cardiovascular drugs and has participated in several trials of lifestyle interventions to prevent and reverse diabetes. Dr. Sides, Dr. Laurent, Dr. Cook, and Dr. Mellor had no conflicts of interest to report.
This story appeared first MDedge.com, Part of the Medscape Professional Network.