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One cup of this common tea daily can fight diabetes, study finds

[Nov. 4, 2023: Staff Writer, The Brighter Side of News]

A groundbreaking study has uncovered a potential ally in the fight against diabetes – a special fermented tea. (CREDIT: Creative Commons)

A groundbreaking study has uncovered a potential ally in the fight against diabetes – a special fermented tea commonly consumed in China known as "dark tea." This beverage, distinct from other teas in both its processing and its benefits, might hold the key to controlling blood sugar levels and thus staving off the onset and progression of diabetes.

Presented recently at the annual meeting of the European Association for the Study of Diabetes in Hamburg, Germany, the findings have sparked excitement in the scientific community, yet also prompted calls for further research.


A Deep Dive into the Study

Researchers from the University of Adelaide in Australia and Southeast University in China collaborated on this expansive study. Their analysis spanned nearly 2,000 adults residing in various parts of China.


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The demographics included participants without diabetes or prediabetes, those showing signs of prediabetes, and those already diagnosed with diabetes. To gain insights into their dietary habits, participants were quizzed about their tea consumption patterns.

Furthermore, a series of tests, ranging from urine glucose to insulin resistance, were conducted to establish the links between tea drinking habits and various health metrics. Once factors related to lifestyle were filtered out, a fascinating pattern emerged.


Drinking any variety of tea daily correlated with a decline in insulin resistance, and an increase in glucose being excreted via urine. Specifically, daily tea consumers exhibited a 15% decreased risk of contracting prediabetes and a notable 28% reduced chance of developing type 2 diabetes compared to their non-tea drinking counterparts.

Daily tea consumers exhibited a 15% decreased risk of contracting prediabetes and a notable 28% reduced chance of developing type 2 diabetes. (CREDIT: Creative Commons)

Highlighting these results, Dr. Tongzhi Wu, co-lead researcher and an associate professor from the University of Adelaide, stated, "Our findings hint at the protective effects of habitual tea drinking on blood sugar management via increased glucose excretion in urine, improved insulin resistance, and, thus, better control of blood sugar."


The Mystique of 'Dark Tea'

"Dark tea" generated the most buzz in this research. It’s essential to clarify that the term doesn’t merely refer to the color of the tea. As pointed out in an article in the journal Chinese Herbal Medicines, dark tea is a unique category among the six major types of teas in China. Its distinguishing feature lies in its production, which involves microbial fermentation.

The subgroup analysis showed that tea consumption of ≥4 cups/day was associated with a reduced risk of type 2 diabetes. (CREDIT: Science Direct)

The fermentation process might be the reason for its pronounced health benefits. Through fermentation, the tea could acquire potent antioxidant and anti-inflammatory properties, enhanced insulin performance and sensitivity, and even promote a diverse gut microbiome.


The study also touched upon the possibility of dark tea emulating the effects of SGLT-2 inhibitors. These are a relatively new class of diabetes drugs, like Jardiance and Farxiga, that enable kidneys to excrete more glucose, consequently reducing blood sugar levels. These inhibitors have been praised for their protective impacts on the heart and kidneys.

Meta-analysis of tea consumption and the risk of type 2 diabetes in subgroup analysis by the type of tea. Weights and study heterogeneity were assessed by a random effects model. Neither green, oolong, nor black tea was associated with diabetes risk. (CREDIT: Science Direct)

Dr. Utpal Pajvani, an associate professor of medicine from Columbia University in New York City, commented on this observation. While he acknowledged the parallel between increased glucose excretion in dark tea drinkers and those taking SGLT-2 inhibitors, he emphasized, "there is insufficient evidence to suggest that drinking dark tea would have beneficial effects that mimic” such drugs.


Additionally, Dr. Abasalon Gutierrez of the McGovern Medical School at UTHealth Houston highlighted other beverages, like green tea and coffee, that could potentially reduce the risk of developing type 2 diabetes. He also mentioned a recent study published in Frontiers which found that kombucha, another fermented beverage, could diminish fasting blood sugar levels. Gutierrez added, "we still need to learn more about the mechanisms of dark tea on the kidneys."

Relationship between tea consumption and the risk of type 2 diabetes in stratification analyses and sensitivity analyses of the present cohort study. Logistic regression showed that tea drinking was not associated with type 2 diabetes risk in all the stratification analyses and sensitivity analyses. (CREDIT: Science Direct)

However, Dr. Zilin Sun, director of Southeast University’s Institute of Diabetes in Nanjing, is optimistic. In a press statement, he suggested that drinking dark tea daily “may be one simple step people can easily take to improve their diet and health."


The Road Ahead

While the initial findings are undoubtedly promising, researchers have expressed caution. This study doesn't confirm but merely suggests that daily tea intake could enhance blood sugar control. There’s an eagerness to delve deeper into this topic to solidify these findings further.

Tea, an infusion made from the leaves of the Camellia sinensis plant using various processes, is the most popular beverage in the world after water. (CREDIT: Science Direct)

This research underscores the rich tapestry of possibilities that traditional beverages like tea can offer.


As science continues to shed light on their potential benefits, we might find ourselves turning to age-old remedies to combat contemporary health challenges. Whether or not dark tea becomes a standard recommendation for diabetes prevention or control remains to be seen, but its potential is undeniably intriguing.

For more science news stories check out our New Discoveries section at The Brighter Side of News.


Note: Materials provided by The Brighter Side of News. Content may be edited for style and length.


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