The #1 Drink To Help Reduce Diabetes Risk, According to New Research

It’s well-documented that eating whole, nutritious foods like vegetables, nuts and oats is known to help to prevent diabetes. And it might even surprise you to learn that increasing your fruit intake could also be beneficial in the same way. But new research suggests that you should also be reaching for the tea kettle! According to a study published on October 3rd in Diabetologia, drinking a cup of dark tea daily helps control blood sugar and may help reduce your risk for developing prediabetes and type 2 diabetes.

What Is the Difference Between Prediabetes and Type 2 Diabetes?

Let’s do a mini recap! Prediabetes is like a warning sign that your body isn't handling blood sugar (AKAnglucose) as well as it should. It’s a condition characterized by elevated blood sugar, but is still below what would qualify as type 2 diabetes. Type 2 diabetes, on the other hand, is a condition characterized by insulin resistance where the body has trouble using glucose for energy. In simple terms, insulin is like a key that helps unlock the cells so that glucose can enter and be used for energy. With insulin resistance, the locks don’t open as well and glucose can't get in as easily, so high amounts of it build up of sugar in the blood which can lead to a myriad of problems.

In this cross-sectional study, researchers worked with 1,923 adults between 20 and 80 years old, most of whom were women (71%). Fifty nine percent of participants had normal blood glucose levels while 23% were living with type 2 diabetes and 18% with prediabetes. Participants also included those who didn't regularly drink tea and those who drank only a single type of tea. They were asked about the frequency of their tea-drinking (i.e. never, occasionally, often and every day) as well as the type of tea they drank (i.e. green, black, dark or other tea).

Researchers examined the association between both the frequency and type of tea consumed and how that impacted excretion of glucose in the urine. People with diabetes typically have kidneys that don’t work as effectively, holding onto glucose instead of excreting it in their urine, which again leads to raised blood sugar levels. The findings suggest that people who drank dark tea every day had more glucose excretions in their urine, a sign that their bodies might be getting rid of glucose more efficiently.

What Is Dark Tea, Anyway?

We’re not talking about your everyday, grocery store black tea. Though, that does come with its own health benefits! Dark tea is a type of Chinese tea that has undergone a microbial fermentation process. Different from full-oxidized Chinese black tea and unoxidized Chinese green tea, dark tea’s claim to fame is that it undergoes a post-production fermentation process. Instead of immediately packaging the tea after it’s made, tea leaves are kept in a controlled environment that's a bit like a compost pile. Often referred to as "pile fermentation" or "wet fermentation," the process involves piling or heaping the tea leaves in a controlled environment, where they are exposed to heat, moisture and microbes for an extended period of time. This fermentation process can last from several months to years, depending on the type of tea. Over time, the tea leaves undergo a natural transformation, much like how cheese or wine ages and develops its unique flavors and characteristics. To find dark teas fermented in this same way, search for “Hei Cha” online or in specialty tea shops and Chinese or East Asian grocery stores.

What Did the Study Find?

People who drank dark tea every day had a 53% lower risk of prediabetes and a 47% lower risk of type 2 diabetes compared to never-tea drinkers. This was after accounting for established risk factors known to drive the risk for diabetes, including age, gender, ethnicity and family history, lifestyle factors like BMI, activity level, alcohol consumption and smoking status, as well as biomarkers like cholesterol, blood pressure and fasting plasma glucose (the amount of glucose in your blood after you've fasted for a set period of time).

Researchers explain that the fermentation process used to make dark tea may yield unique compounds that have potent antioxidant and anti-inflammatory effects, improve insulin sensitivity, boost pancreatic function and alter gut bacteria in helpful ways. Dark tea drinking was also associated with increased glucose excretion in the urine and lower insulin resistance which, if you remember from above, are two factors that allow for better blood sugar management overall.

According to co-lead author, Dr. Tongzhi Wu, dark tea might even have benefits similar to a new anti-diabetes drug called SGLT2 inhibitors. Very simply put, SGLT2 inhibitors are like a “sponge wringer” that helps the kidneys squeeze out extra glucose from the body and excrete it through the urine. The findings suggest that the compounds in dark tea could work like SGLT2 inhibitors by affecting how the kidneys handle glucose. These effects were most pronounced in daily dark tea drinkers versus occasional drinkers. The findings suggest that “drinking dark tea every day has the potential to lessen type 2 diabetes risk and progression through better blood sugar control,” says Wu.

Despite the promising findings, researchers can’t yet be certain that an observational study alone can guarantee that drinking tea every day directly improves blood sugar control via these mechanisms. They also can't rule out the possibility that other lifestyle or physiological factors might have influenced the results. That said, it seems like dark tea is likely to contribute and what they have found so far is very promising. To further validate their findings, EurekaAlert reports that 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.” So stay tuned!

The Bottom Line

While more research is underway, the findings hint that making a simple swap to dark tea could be one easy, delicious way to fend off diabetes. As Wu says, “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.” So consider brewing a comforting cup of dark tea each morning or afternoon for those blood sugar-stabilizing benefits. As part of an overall balanced diet and active lifestyle, it could help keep diabetes risk at bay.