Chinese and Australian researchers have shown that daily consumption of black tea could promote the elimination of glucose by the kidneys. But not just any…
Drinking black tea every day helps maintain blood sugar levels (blood sugar level) and would thus reduce the risk of type 2 diabetes of 47%, suggests a study carried out by the University of Adelaide (Australia) and the Southeast University (China), the results of which were presented at the annual meeting of the European Association for the Study of Diabetes in Hamburg (October 2 to 6, 2023). To understand the role of tea, researchers analyzed and compared the blood sugar levels of 1,923 participants (562 men and 1,361 women aged 20 to 80) from 8 Chinese provinces. All participants provided information on the frequency of tea consumption (never, occasionally, often, daily) and on the type of tea that they drank (green, black or others).
All tea drinkers took their drink without milk or sugar
Among the participants (who drank their tea plain, without milk or sugar), 436 had diabetes, 352 had prediabetes and 1,135 had normal blood sugar levels. Differences in age, gender and lifestyle were also taken into account. After evaluating the concentration of fasting urinary glucose, measured insulin resistance and recorded the glycemic status (history of type 2 diabetes, taking antidiabetic medications, or abnormal oral glucose tolerance test) of each participant, the researchers found that people who drank tea daily compared to those who never drank it:
→ Absorbed less glucose in the kidneyswhich led to a greater release of glucose into the urine and contributed to lower blood sugar.
→ Had better insulin resistance (insulin resistance can be considered a prediabetic state, a warning sign of developing diabetes)
→ Had a reduced risk of 15% prediabetes and a reduced risk of 28% type 2 diabetes
Compounds capable of modulating glucose elimination in the kidneys
While the study does not say how much tea was drunk per day, the benefits on blood sugar were more pronounced among daily drinkers of black tea (called Pu-erh among the Chinese): 53% reduction in having prediabetes and 47% reduction in having type 2 diabetes. “The beneficial effects of drinking black tea may come from the way teas such as Pu-erh are produced, which involves microbial fermentation, a process that can produce unique bioactive compounds (in particular alkaloids, free amino acids, polyphenols, polysaccharides).” These compoundscould directly or indirectly modulate glucose excretion in the kidneysan effect imitating (to a certain extent) that of certain drugs against type 2 diabetes (SGLT-2 inhibitors or gliflozins)“, explains Professor Zilin Sun of Southeast University, co-author of the study in a statement published on EurekaAlert.
“It is difficult to apply the results to a wider population”
This study suggests that “daily consumption of black tea has the potential to reduce the risk and progression of diabetes type 2 thanks to better blood sugar control. When you look at all the different biomarkers associated with habitual black tea consumption, this can be a simple measure for people to implement.” However, “Given that this is an observational study with only a small number of participants in China, it is difficult to apply results to a wider populationand we cannot establish a cause and effect relationship between black tea and its role in regulating glucose in our body“, he continues. A more in-depth double-blind study is underway. The results are expected to be 2024.