After accounting for differences in age, sex, and clinical and lifestyle factors, the analysis found that drinking tea every day was associated with an increase in urinary glucose excretion (UGCR by 0.11 mmol/mmol) and a reduction in insulin resistance (TyG by -0.23), as well as 15% lower risk for prediabetes and 28% reduced risk for type 2 diabetes, compared with never tea-drinkers.
These favorable health effects were most robust for dark tea drinkers, with consumption of dark tea associated with an increase in UGCR by 0.16 mmol/mmol and a reduction in TyG by 0.31.
According to Associate Professor Wu: “These findings suggest that the actions of bioactive compounds in dark tea may directly or indirectly modulate glucose excretion in the kidneys, an effect, to some extent, mimicking that of sodium-glucose co-transporter-2 (SGLT2) inhibitors, a new anti-diabetic drug class that is not only effective at preventing and treating type 2 diabetes, but also has substantial protective effects on the heart and kidneys.”
Co-lead author Professor Zilin Sun from Southeast University adds, “Our findings suggest that drinking dark tea every day has the potential to lessen type 2 diabetes risk and progression through better blood sugar control. When you look at all the different biomarkers associated with habitual drinking of dark tea, it may be one simple step people can easily take to improve their diet and health.”
Despite the promising findings, the authors caution that as with any observational study, the findings cannot prove that drinking tea every day improves blood sugar control by increasing urinary glucose excretion and reducing insulin resistance, but suggest that they are likely to contribute. They are currently conducting a double-blind, randomized trial to investigate the benefits of dark tea on blood glucose control in people living with type 2 diabetes to validate their findings. In addition, they cannot rule out the possibility that residual confounding by other lifestyle and physiological factors may have affected the results.
Meeting: Annual Meeting of the European Association for the Study of Diabetes (EASD)
