Normally blood sugar levels should be less than 126 milligrams per deciliter, or mg/dl. But in cases of high blood glucose, which is also known as hyperglycemia, levels are 160 mg/dl or above. The condition, which characterizes diabetes, develops because your body doesn't produce any or enough insulin, or it cannot properly use the insulin it produces. One drink that will help lower blood sugar is green tea.
What Is Green Tea?
Like other teas, green tea comes from the camellia sinensis plant. However, unlike oolong or black tea, green tea is made from unfermented leaves and contains the highest amounts of antioxidants known as polyphenols, according to the University of Maryland Medical Center. Antioxidants help to fight free radicals that damage cells and DNA and contribute to aging and disease.
Green Tea and Diabetes
Green tea has long been used to regulate blood sugar levels in people with diabetes. It may also play a role in preventing type 1 diabetes or slowing its progression once you have it. The University of Maryland Medical Center reports that clinical studies have shown that green tea supplements in powder form can reduce hemoglobin A1c levels in people with prediabetes. Hemoglobin A1c levels indicate how well your blood sugar is under control.
In one study published in the journal "BMC Pharmacology" in 2004, a team of Chinese and Japanese researchers found that green tea improved glucose metabolism in healthy participants. The drink also lowered blood glucose levels in diabetic rats. The researchers indicate that a blood protein may be responsible for green tea's ability to lower blood sugar, but they add that more studies are necessary.
Amount and Form
Green tea is available in tea bags, leaf, liquid extract or capsule form. Your best choice is a supplement as they provide standardized amounts of green tea polyphenols. A cup of green tea contains about 50 to 150 mg of polyphenols. A general recommendation is two to three cups of green tea daily, according to the University of Maryland Medical Center. For green tea extract, 100 to 750 mg of polyphenols is recommended.
When taken in high doses, green tea can cause a range of side effects due to its caffeine content. Some side effects include dizziness, heart palpitations, headaches, insomnia and loss of appetite. Also, green tea can interact with medications such as blood pressure, chemotherapy and heart drugs, antibiotics and the cold medications or weight-loss products that contain phenylpropanolamine. Seek more advice from your doctor about regulating your blood sugar and taking green tea.
- American Diabetes Association: Hyperglycemia (High Blood Glucose)
- “BMC Pharmacology”; Effect of Green Tea on Blood Glucose Levels and Serum Proteomic Patterns in Diabetic (Db/Db) Mice and on Glucose Metabolism in Healthy Humans
- University of Maryland Medical Center: Green Tea
- National Center for Complementary and Alternative Medicine: Green Tea
- Joslin Diabetes Center: High Blood Glucose: What It Means and How To Treat It