08 July, 2011
Herbal teas are made from fruits, flowers, roots, bark and other parts of plants other than the tea plant, Camellia sinensis. Evidence of people consuming herbal teas dates back to ancient Egypt and China. For their pleasant flavors and aromas, as well as their purported medicinal effects, herbal teas are a welcome addition to a healthy lifestyle. Some herbal teas are sought after particularly for their reputed ability to stabilize blood sugar.
Sage tea, a beverage commonly consumed in Turkish-speaking countries, contains a compound called rosmarinic acid that may offer blood sugar regulating effects, according to a study published in the March 2011 issue of the journal "Molecular Nutrition and Food Research." In the study on laboratory animals, two weeks of sage tea consumption stabilized fasting blood glucose levels and inhibited an increase in glucose absorption following carbohydrate meals. The researchers concluded that sage tea has blood sugar lowering effects at the intestinal level, modulating glucose absorption.
Bilberry, a relative of blueberry, is commonly consumed as a tea and contains among the highest quantities of antioxidant anthocyanin compounds. Bilberry extract was found to have blood sugar lowering properties, in a study published in the March 2010 issue of the "Journal of Nutrition." In the study on laboratory animals, bilberry extract significantly reduced blood sugar levels and increased insulin sensitivity by promoting transport of glucose from the blood into muscles and by suppressing glucose and lipid production in the liver.
Hibiscus tea, made from hibiscus flowers, showed blood sugar and cholesterol lowering properties in a study published in the November 2003 issue of the "Journal of Ethnopharmacology." In the study on laboratory animals, hibiscus supplementation for 21 days lowered blood sugar by as much as 46 percent and insulin by 14 percent. The extract also lowered total cholesterol by 22 percent and triglycerides by 30 percent. Of note, hibiscus increased HDL cholesterol, the good form of cholesterol, by 12 percent, whereas the diabetes drug glibenclamide raised HDL levels by 1 percent, in the study.
Cinnamon tea stabilizes blood sugar by regulating glucose transportation and decreasing insulin levels, according to a study published in the November 2010 issue of the journal "Phytomedicine." In the study using laboratory animals, cinnamon extract influenced genes in fat cells that increase glucose movement out of the blood, and decreased expression of at least four genes that regulate insulin levels. Cinnamon also affected production of adipokines -- hormones produced by fat cells as a feedback system to control appetite, blood sugar and weight. The researchers concluded that cinnamon's health benefits may be due to its influence on the signals and hormones produced by fat cells to regulate blood sugar.
- "Molecular Nutrition and Food Research"; Rosmarinic Acid, Major Phenolic Constituent of Greek Sage Herbal Tea, Modulates Rat Intestinal SGLT One Levels with Effects on Blood Glucose; Azevedo MF, et al.; March 2011
- "Journal of Nutrition"; Dietary Anthocyanin Rich Bilberry Extract Ameliorates Hyperglycemia and Insulin Sensitivity Via Activation of AMP Activated Protein Kinase in Diabetic Mice; Takikawa M, et al.; March 2010
- "Journal of Ethnopharmacology"; Effect of Hibiscus Rosa Sinensis Linn. Ethanol Flower Extract on Blood Glucose and Lipid Profile in Streptozotocin Induced Diabetes in Rats; Sachdewa A, et al.; November 2003
- "Journal of Cardiovascular Pharmacology"; Blockade of Nitroxidative Stress by Roasted Licorice Extracts in High Glucose Exposed Endothelial Cells; Choi YJ, et al.; October 2008
- green tea in tea cup image by Grzegorz Szlowieniec from Fotolia.com