Is Oolong Tea Good for Diabetes?

Partly: unsweetened oolong tea can be a good choice for people with diabetes when it replaces a sugary drink, reducing carbohydrate intake that can raise blood sugar. The evidence for oolong tea as a blood sugar treatment is limited, so it should complement—not replace—diabetes care.

When is oolong tea a good choice for diabetes?

Plain oolong tea can fit into a diabetes eating plan. Its clearest benefit is as an unsweetened alternative to drinks that contain added sugar, rather than as a proven way to lower blood glucose.

That distinction matters whether you have type 1 or type 2 diabetes. Oolong tea does not replace prescribed medication, glucose monitoring or the eating and activity plan you have discussed with your care team. The clinical trial described below involved people with type 2 diabetes, so its results should not be assumed to apply to type 1 diabetes.

How might oolong tea affect blood sugar?

Replacing a sugary drink with unsweetened oolong tea reduces the carbohydrate from that drink. This can help limit the rise in blood glucose associated with consuming the sugar, although your overall meal and other factors also affect your reading.

Oolong tea contains plant compounds called polyphenols that have been investigated for possible effects on carbohydrate metabolism. It is not clear whether compounds in brewed oolong tea reliably improve blood sugar management in people with diabetes.

Oolong tea also usually contains caffeine, which can affect blood glucose differently from person to person. For a broader look at drink choices, see the best drinks for blood sugar.

What does the research say about oolong tea and diabetes?

In a small randomized crossover trial, 20 people with type 2 diabetes drank 1,500 mL of oolong tea or water daily for 30 days each while continuing their prescribed diabetes medicines. Their plasma glucose and fructosamine, a marker of recent average blood glucose, fell from starting levels during the oolong tea period; the water period did not show similar decreases.

This is encouraging but limited evidence. The trial was small and short, and it did not establish whether oolong tea prevents diabetes complications or changes medication needs over the long term. It also does not prove that a smaller amount of oolong tea will lower blood sugar.

The amount used was a research dose, not a recommended daily intake. Do not try to reproduce it as a substitute for diabetes treatment or assume that more oolong tea will produce a better result.

How can you use oolong tea safely?

Choose plain, unsweetened oolong tea and prepare it according to the package directions. You can drink it hot or chilled; avoid adding sugar, honey or syrup if your goal is to replace a sugary drink.

For bottled oolong tea, check the nutrition label and ingredient list. Sweetened versions can contain added sugar, while milk or flavored creamers can also contribute carbohydrates. Count those carbohydrates as you normally would under your diabetes plan.

Drink an amount that fits your usual fluid and caffeine needs rather than aiming for the amount used in the trial. If caffeine affects your sleep or makes you feel jittery, consider a decaffeinated oolong tea or discuss your options with your care team.

Follow your usual glucose-monitoring plan when changing a drink you consume regularly. Meals, activity, illness and medication can all influence readings, so a single reading cannot establish that oolong tea caused a change.

Who should be careful, and when should you seek help?

If you use insulin or a sulfonylurea, you may be at risk of low blood sugar. If a sugary drink is part of your usual meal or medication plan, ask your diabetes care team about changing that routine. Do not replace the fast-acting carbohydrate you use to treat a low with oolong tea, and do not adjust or stop medication on your own.

Ask a clinician about caffeine and fluids if you are pregnant or breastfeeding, have kidney disease or a fluid restriction, have heart rhythm problems, or are considering oolong tea for a child with diabetes. Your care team can help you decide what fits your circumstances.

If you have symptoms of low blood sugar and can swallow safely, follow your diabetes care plan for treating a low. Seek emergency help for unconsciousness, a seizure or an inability to swallow; use prescribed emergency glucagon if available, and do not give food or drink to someone who cannot swallow safely.

Seek emergency care for high blood sugar symptoms such as vomiting, abdominal pain, rapid breathing or unusual drowsiness. Contact your diabetes care team if your readings are repeatedly outside your agreed range, even if you feel well.