How Dark Tea Can Help Prevent Diabetes

A daily cup of dark tea may help reduce the risk of type 2 diabetes in adults, a new study finds. According to research presented at this year’s Annual Meeting of The European Association for the Study of Diabetes, people who consume dark tea every day have a 53% lower risk for prediabetes and 47% lower risk for type 2 diabetes.

Prediabetes is characterized by high blood sugar levels, while type 2 diabetes involves insulin resistance, where the body struggles to process sugar as fuel. “This study showed in a general Chinese population that habitual tea consumption, particularly dark tea, was associated with reduced risk of both prediabetes and diabetes,” said Tongzhi Wu, MD, PhD, the study’s co-lead author and associate professor from the University of Adelaide.

Wu explained that previous studies have highlighted numerous benefits of tea consumption, such as reduced inflammation and improved insulin sensitivity. The new research focused on another aspect of diabetes risk: increased urinary glucose excretion. “Our study showed that it is associated with increased urinary glucose excretion, which may also contribute to its glycemic benefits,” Wu said.

How Dark Tea Impacts Blood Sugar and Diabetes Risk

Caroline Messer, MD, an endocrinologist at Northwell Lenox Hill Hospital, explained that dark tea might work with the kidneys to excrete glucose into the urine, thereby lowering blood sugar levels. “Dark tea might work with the kidneys to get glucose out of the blood and into the urine, and by improving insulin sensitivity in muscle and fat,” she said.

Research shows that dark tea, specifically black tea, is filled with antioxidants which can help reduce oxidative stress and lower the risk of developing chronic illnesses. A 2018 study demonstrated the impact of drinking black tea on blood sugar levels by having participants drink a high-sugar beverage paired with either a low or high dose of black tea or a placebo. The people who drank the low or high dose of black tea had lower blood sugar compared to those who drank a placebo.

“The theaflavins and thearubigins in dark tea may reduce cholesterol and blood sugar levels,” said Divya Yogi-Morren, MD, medical director of the Cleveland Clinic Pituitary Center. Dark tea also affects the type of bacteria in the gut, promoting the growth of good bacteria and inhibiting the growth of bad bacteria, which may help reduce diabetes risk.

Additional Benefits of Dark Tea

Dark tea may modulate glucose excretion in the kidney, resulting in more glucose being excreted from the body and lowering the risk of high blood sugars and diabetes. Additionally, the unique fermentation process of dark tea creates bioactive compounds with antioxidants and anti-inflammatory effects that increase insulin sensitivity and the performance of beta cells in the pancreas.

Diabetes is caused by either decreased insulin production from the pancreas or reduced insulin sensitivity. By improving insulin production and sensitivity, there is a lower chance of developing diabetes. Dark tea may enhance insulin action, improve insulin resistance, protect the beta cells in the pancreas that produce insulin, remove free radicals from the body, and decrease inflammation.

If you’re choosing a dark tea to add to your pantry, opt for a natural dark tea without added artificial ingredients. While more research is needed to confirm dark tea’s impact on diabetes risk, adding dark tea to your routine is a worthwhile endeavor. “Our observations support the concept of regularly drinking tea, particularly dark tea, as a safe and inexpensive dietary approach to reduce the risk of prediabetes and diabetes,” Wu said.