The body uses the hormone insulin to keep blood sugar levels within a healthy range. Chronically elevated blood sugar levels can lead to inflammation of your blood vessels, which can disrupt nutrient flow to your organs. This can increase your risk for diabetes, impaired kidney dysfunction and cardiovascular disease. Drinking tea daily may help lower blood sugar levels.
Mechanism
Tea contains high levels of antioxidants, which might play a role in regulating blood sugar, according to research reported in the February 2008 issue of the "Journal of Food Biochemistry." Researchers at the University of Massachusetts discovered that black, oolong, white and green teas were effective for inhibiting the activity of alpha-glucosidase, an enzyme that stimulates glucose absorption by the small intestine. This prevents glucose from reaching your bloodstream, thereby helping control blood sugar levels.
Black Tea
Black tea might increase insulin levels and reduce blood glucose levels. Scientists at King's College London in the United Kingdom studied the impact of black tea on glucose and insulin levels. They observed that participants consuming 75 g of glucose in 250 ml of water with 1 g of black tea experienced increases in insulin levels and lower blood glucose levels after the drink compared with those who consumed 75 g of glucose in 250 ml of water without black tea. The findings were published in the October 2007 issue of the "Journal of the American College of Nutrition."
Green Tea
Scientists at Toyama Medical and Pharmaceutical University in Japan examined the impact of green tea consumption in healthy men and women. They discovered that participants consuming 75 g of glucose in 150 ml of water with 1.5 g of green tea powder experienced lower glucose levels after the drink compared with those who had the same drink without green tea powder, according to research published in the August 2004 issue of "BMC Pharmacology."
Caffeine
Black and green tea contain between 10 and 80 mg of caffeine per 8 oz., according to the Linus Pauling Institute. Excess caffeine intake can lead to insomnia, nervousness and increased heart rate. If you experience any of these symptoms, reduce your tea intake or choose decaffeinated tea.
References
- "Journal of Food Biochemistry"; Inhibitory Potential of Wine and Tea Againist Alpha-Amylase and Alpha-Glucosidase for Management of Hyperglycemia Linked to Type-2 Diabetes; Y.I. Kwon et al.; February 2008
- "Journal of the American College of Nutrition"; The Effect of Consuming Instant Black Tea on Postprandial Plasma Glucose and Insulin Concentrations in Healthy Humans; J.A. Bryans et al.; October 2007
- "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; H. Tsuneki et al.; August 2004
- Linus Pauling Institute; Tea; January 2008
