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New research suggests that drinking a daily cup of dark tea can help control blood sugar and reduce your risk of type 2 diabetes by 47%. pixdeluxe/Getty Images
  • A new study suggests that drinking dark tea daily may reduce the risk of developing type 2 diabetes.
  • Dark tea consumption was linked with a 53% lower risk of prediabetes and 47% reduced risk of type 2 diabetes.
  • Researchers suggest drinking dark tea increases glucose excretion in urine and improves insulin resistance.
  • Experts say drinking dark tea is a good blood sugar management tool, but you should consider your overall diet too.

A cup of tea is a daily staple for many people around the world. Now, a new study has found that drinking dark tea specifically may reduce your diabetes risk.

Drinking dark tea every day may help to mitigate type 2 diabetes risk and progression in adults through better blood sugar control, according to new research shared at this year’s Annual Meeting of The European Association for the Study of Diabetes (EASD) in Hamburg.

Researchers from the University of Adelaide in Australia and Southeast University in China found that compared with never tea drinkers, daily consumers of dark tea had 53% lower risk for prediabetes and 47% reduced risk for type 2 diabetes.

This was even after taking into account established diabetes risk factors, such as age, gender, ethnicity, and body mass index (BMI).

The cross-sectional study included 1,923 adults. 436 of the participants were living with diabetes, 352 had prediabetes, and 1,135 had normal blood glucose levels. The cohort included non-habitual tea drinkers and those with a history of drinking only a single type of tea.

The researchers examined the association between both the frequency and type of tea consumption and the excretion of glucose in the urine, insulin resistance, and glycaemic status.

Commenting on the findings, co-lead author associate professor Tongzhi Wu said: “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. These benefits were most pronounced among daily dark tea drinkers.”

So, is drinking dark tea daily an effective tool for reducing your risk of type 2 diabetes?

Nutritionist Natalie Burrows is impressed by the findings. “I’m not hugely surprised by the findings as we know how antioxidant rich tea leaves are and how antioxidants and anti-inflammatory compounds can support vascular health and inflammation,” she says.

“However, the degree to which daily consumption of unsweetened dark tea can improve an individual’s risk of type 2 diabetes is remarkable. It goes to illustrate once again how powerful nature can be when we consume natural foods.”

Burrows says tea leaves have been shown to contain beneficial compounds that benefit the body in a multitude of ways.

“Catechins, a polyphenol (AKA an antioxidant) which are found in tea have been shown to be responsible for the regulation of insulin, blood sugar, and energy metabolism by managing the signaling pathways,” she explains.

The study suggests that drinking dark tea may contribute to a reduction in diabetes risk for two reasons. Firstly, it improves insulin resistance which means being better able to control your blood sugar.

Secondly, it contributes to increased glucose excretion in your urine, meaning there is less blood sugar to actually control.

Like Burrows, nutritionist Harry Snell believes this is down to the polyphenol content of dark tea.

He explains that the hypoglycemic effects of polyphenolic compounds may inhibit carbohydrate digestion, glucose absorption, and the stimulation of insulin secretion, all of which lead to better blood sugar control.

It’s important to remember that the study looks at the effects of dark tea specifically. It’s a kind of fully oxidized tea that shouldn’t be confused with black tea.

“Dark tea has undergone microbial fermentation,” Snell explains. “It’s referred to as ‘dark’ because the leaves are oxidized and change color, a bit like the rusting process with iron.”

A common type of dark tea is Pu-erh from China which is available online and in health shops.

Explaining the differences between dark tea, and other popular tea types, Burrows says black tea is highly oxidized, whereas green tea is unoxidized.

Meanwhile, yellow tea is slightly fermented and dark tea is post-fermentation.

“The addition of fermentation may play an important role in the impact dark tea has on blood sugar regulation,” she explains.

So, would experts recommend dark tea as a blood sugar management tool?

“The results are positive and drinking dark tea is certainly a low-resistance way to get potential important health effects. There is also the added benefit of hydration, which can affect glucose response,” says Snell.

However, he believes there are some things to consider, including:

  • The cost of specialist tea
  • Taste (and the addition of sugar to change it)
  • Availability (dark tea is not available in many supermarkets)

Similarly, Burrows would recommend dark tea as a blood sugar management tool but advises drinking it unsweetened.

“Adding sugar or sweetener to tea will dissolve its recognized benefits for blood sugar,” she warns.

“I would also recommend enjoying different teas; dark, black, green, and white for all the various benefits they have on lowering blood sugar and improving inflammation and antioxidant status,” she adds.

One thing is clear: the foods and drinks we consume can play a major role in our health outcomes. The study shows that dark tea reduces diabetes risk, but it’s important to consider your diet as a whole.

“No single thing is a cure by itself,” Snell points out. “Rather, as part of a healthy diet, many different foods can be used effectively to improve health markers.”

With that in mind, how else can you reduce your diabetes risk through diet? Burrows says reducing your overall intake of sugar should be your first port of call. She recommends eliminating or swapping refined carbohydrates such as white bread, pasta, rice, and pastries.

“Although these may not appear sugary, they break down to sugar during digestion, without the added benefit of fiber to slow the impact on blood sugar down.”

Cutting out ultra-processed foods is another important step. “These will only increase inflammation as they contain more sugar, salt, and fat. They have been linked to an increase in obesity, type 2 diabetes, and increased risk of heart attack and strokes too,” Burrows explains.

Her advice is to eat as close to nature as possible. This, she explains, will encourage the consumption of whole foods with high fiber, antioxidants, and anti-inflammatory compounds that help to regulate blood sugar.

Finally, stay hydrated. “Dehydration will increase your blood sugar levels,” Burrows warns. “The average person will require around two liters of water a day to replace what is used and lost during the usual function of the body, so drink up.”

The results of this new study linking daily dark tea consumption with a reduction in diabetes risk are certainly promising. It’s also an easy and enjoyable way to do something good for your health.

However, it’s important to remember that no one food or drink is a magic bullet when it comes to your overall health.

By all means, drink dark tea daily, but it’s important to consider your diet as a whole, particularly when it comes to blood sugar control.