Tea and Diabetes

One of the world’s most beloved drinks, tea forms an important part of the daily habits of billions. It’s also been celebrated for its health benefits for centuries.

Is tea actually good for you? And is tea suitable for people with diabetes? This article will explore the science behind the hype.

The Many Potential Health Benefits of Tea

Tea is widely considered a healthy beverage, and there has been a ton of research into its potentially positive effects.

Polyphenols are the key to most of tea’s health claims. Polyphenols, chemicals found in plants, are considered “highly essential functional foods in our diet.” These micronutrients are associated with improved cholesterol, blood pressure, inflammation, and insulin resistance. Tea is especially rich in flavonoids, a type of polyphenol with powerful antioxidant effects.

According to our partners at Everyday Health, there is evidence tea can help lower the risk of a huge variety of health issues, including:

Cardiovascular disease
High blood pressure
High LDL (“bad”) cholesterol
Insulin resistance
Neurocognitive disorders
Poor sleep quality
Gastrointestinal symptoms

Black Tea, Green Tea, Herbal Tea?

Most discussion among nutrition and public health authorities centers around black and green tea. But that’s really just scratching the surface.

Here are just a few of the additional options:

Oolong tea is kind of halfway between green and black teas: The leaves are only partially oxidized, resulting in a lighter color and flavor than black tea.
Matcha is a special type of green tea that is shielded from direct sunlight while it’s growing; it may contain a higher concentration of polyphenols.
Dark tea, not to be confused with black tea, is fermented for a mellow flavor. It’s most popular in China; the most famous variety in the West is pu-er (or pu-erh) tea.
Herbal tea isn’t really tea, botanically speaking. It can be brewed from many different plants. Popular options include peppermint, chamomile, and ginger, all of which are believed to offer health benefits. It’s difficult to generalize about herbal tea because there is so much nutritional diversity within the category.
Yerba mate isn’t closely related to tea; it’s a type of holly that contains caffeine and is associated with many health benefits.

Which is the healthiest? It’s probably impossible to say as the research isn’t definitive enough. Every one of these options has reams of encouraging research behind it. You’d probably be wise to just choose whichever tea you like best.

So, Is Tea Good for You?

The science suggests that tea might be good for you, and that the benefits likely outweigh any potential harms.

A massive 2019 umbrella review that examined nearly 100 meta-analyses concluded that “tea consumption indicates reduced risks of total mortality, cardiac death, coronary artery disease, stroke, and type 2 diabetes,” and that the benefits seemed maximized “at two to three cups per day.”

Some of the data is impressive. A 2022 study found that drinking two or three cups of tea per day resulted in a 13 percent reduced likelihood of early death.

That doesn’t mean that a few cups of tea will create immediately obvious health improvements. Though there has been a truly immense amount of study on this question, health experts generally only recommend tea cautiously, and unfailingly note that more controlled experimentation is needed to be sure of the beverage’s effects. Much of the research into tea’s health benefits has been in the form of observational studies, considered a less reliable form of evidence.

Health authorities tend to give tea a lukewarm endorsement. Harvard’s School of Public Health, for example, states that studies “show promise.” The Academy of Nutrition and Dietetics says that “although more research is needed to pin down all of its benefits, tea can be part of a healthy eating pattern.”

One of tea’s chief benefits may be the fact that people tend to use it instead of less wholesome beverages. You don’t need a degree in nutrition science to know that a cup of green tea in the afternoon is probably healthier than a soda or a Starbucks Mocha Frappuccino. Tea is naturally zero-calorie, zero-carbohydrate, and zero-sugar. Of course, many people prefer their tea with sugar and milk, but even a sweet and creamy tea may be healthier than some of the alternatives.

Tea and Diabetes

Tea, a naturally zero-carb beverage, can be a great drink for people with diabetes, especially if it’s replacing other less-healthy choices such as soda.

It’s also possible that tea has special health benefits for glucose metabolism. There’s plenty of evidence that tea is associated with lower diabetes risks:

A 2014 systematic review found that people who drink tea are less likely to develop type 2 diabetes.
Green tea may decrease A1C, according to a 2013 study.
A 2017 experiment suggested that black tea, when consumed along with sugar, can reduce post-prandial glucose spikes.

Tea can also help with both weight loss and hydration, two factors of particular interest to many people with diabetes.

The latest evidence comes from a new study in Diabetologia from researchers in Australia and China. This observational study examined the habits of about 2,000 Chinese adults. They found that, compared with adults who did not drink tea, those who drank tea daily were less likely to have prediabetes or type 2 diabetes, even after adjusting for risk factors such as age, BMI, and blood pressure. The effect was strongest for drinkers of dark tea, such as pu-er. Daily drinkers of dark tea were about 50 percent less likely to have prediabetes or diabetes.

The researchers speculated that the tea might help lower blood sugar levels by directly modulating how the kidneys reabsorb sugar. Tea might work much the same way that SGLT2 inhibitors do, by causing the body to take sugar out of the bloodstream and put it into the urine, with which it exits the body.

There’s also a wealth of evidence for the antidiabetic effects of various herbal teas, including rooibos and ginger teas.

Tea and Short-Term Blood Sugars

Many regular coffee drinkers have noticed that coffee, even zero-carb black coffee, can raise your blood sugar. Caffeine is the culprit. Research shows that caffeine leads directly to glucose spikes.

Can tea have the same effect? According to the Mayo Clinic, a cup of coffee has about twice as much caffeine as a cup of black or green tea, which suggests that it might have twice as strong an effect on your blood sugar levels.

In the Diabetes Daily forums, there is a lot of discussion on tea’s effect on blood sugar levels, but it’s our impression that relatively few people are concerned that tea creates blood sugar rises. In fact, some people believe that tea helps their blood sugar go down.

Either way, even if caffeine does cause transient blood sugar rises, in the long term it appears to have a mostly positive effect on glucose metabolism. Regular coffee drinking, for example, is associated with a reduced risk of type 2 diabetes.

Tea, Cream, and Sugar

It should go without saying, but it’s important to remember that added sugar in tea (including natural sweeteners such as honey and agave syrup) can have a huge effect on blood sugar.

If you prefer prepared tea drinks, whether hot or cold, be very careful to check the nutrition facts. Prepared beverages from sources like Starbucks and Dunkin’ can pack in an amazing amount of sugar. And a bottle of Snapple has just about as many carbohydrates as a can of Coca-Cola.

The saturated fat and calories from the added dairy may also work against your diabetes management goals.

Thankfully, it’s never been easier to find a zero-carb sweetener that you like.


There is a wealth of evidence suggesting that tea can have beneficial health effects, improving your metabolism and reducing the risk of chronic disease. Though the science isn’t exactly settled, experts agree that tea is a great beverage to work into a healthy diabetes-friendly diet.

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8 Teas to Drink for a Healthier Body and Mind. Everyday Health. September 13, 2023.

7 Potential Health Benefits of Matcha. Everyday Health. February 27, 2023.

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Inoue-Choi M, Ramirez Y, Cornelis MC, Berrington de González A, Freedman ND, Loftfield E. Tea Consumption and All-Cause and Cause-Specific Mortality in the UK Biobank : A Prospective Cohort Study. Ann Intern Med. September, 2022.

Tea. Harvard T.H. Chan School of Public Health. April, 2023.

Gordon, Barbara. The Health Benefits of Tea. Eatright.org. November 2, 2022.

Yang, Jian et al. “Tea consumption and risk of type 2 diabetes mellitus: a systematic review and meta-analysis update.” BMJ open. July 22, 2014.

Liu K, Zhou R, Wang B, Chen K, Shi LY, Zhu JD, Mi MT. Effect of green tea on glucose control and insulin sensitivity: a meta-analysis of 17 randomized controlled trials. Am J Clin Nutr. August, 2013.

Butacnum A, Chongsuwat R, Bumrungpert A. Black tea consumption improves postprandial glycemic control in normal and pre-diabetic subjects: a randomized, double-blind, placebo-controlled crossover study. Asia Pac J Clin Nutr. January, 2017.

Study suggests drinking dark tea every day may help control blood sugar to reduce diabetes risk. Medical Xpress. October 2, 2023.

Mazibuko-Mbeje, Sithandiwe E et al. “Aspalathin, a natural product with the potential to reverse hepatic insulin resistance by improving energy metabolism and mitochondrial respiration.” PloS one. May 1, 2019.

Shidfar, Farzad, Rajab, Asadollah, Rahideh, Tayebeh, Khandouzi, Nafiseh, Hosseini, Sharieh and Shidfar, Shahrzad. “The effect of ginger (Zingiber officinale) on glycemic markers in patients with type 2 diabetes” Journal of Complementary and Integrative Medicine. February 10, 2015.

James D. LaneMark N. FeinglosRichard S. Surwit; Caffeine Increases Ambulatory Glucose and Postprandial Responses in Coffee Drinkers With Type 2 Diabetes. Diabetes Care. February 1, 2008.

Caffeine content for coffee, tea, soda and more. Mayo Clinic. April 26, 2022.

Increasing daily coffee consumption may reduce type 2 diabetes risk. Harvard T.H. Chan School of Public Health. April 24, 2014.

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