Tea and Diabetes Mellitus

Tea Q&A with Dr. Saleeby for Tea Experience Digest Magazine

Q: My mother is a diabetic. I've heard tea is good for diabetics as long as they don't add sugar. Is this true? Do you think that by drinking tea I can avoid getting diabetes, too?

A: Green, Oolong and Black tea appear to be beneficial in reducing risk of Diabetes Mellitus type II (DM II). Dr. Richard Anderson, at the USDA's Beltsville Human Nutrition Research Center in Maryland published such findings in animal trials in the Journal of Agricultural & Food Chemistry in 2002. It appears from the research that epigallocatechin gallate (EGCG) is the most insulin-enhancing chemical of all those found in tea. The researchers studied other herbal teas, spices and plants but found tea as the most potent in reducing diabetes risk. Tea produced a 15-fold increase in insulin activity. EGCG showed evidence of working with insulin receptors on cells to enhance the effects of circulating insulin. Cinnamon was another plant that showed promise. Caffeine does not appear play a major role, thus de-caffenated teas had the same beneficial effect as regular tea. A later study published in 2005 in the International Journal of Obesity (involving some seven-thousand human subjects) by Dr. J. Greenberg showed a reduction in DM risk by tea drinkers only in the non-elderly population who had previous weight-loss.

Adding milk, nondairy or soy creamers to your tea does inhibit the insulin boosting effect. Lemon juice however did not have a negative effect on the tea. Adding simple sugars would not necessarily be a problem for a non-diabetic, but a sugar alternative such as a non-caloric commercial sweetener or a natural sugar alternative such as stevia may be healthier and recommended for the diabetic patient. The diabetes lowering effects of tea only last a few hours, therefore making it necessary to drink tea several times throughout the day to benefit from its properties. My recommendation is to drink three to four cups of tea (Camellia sinensis) a day flavored with lemon or cinnamon as opposed to sugar.

References:

Tsuneki, H., et al, Effect of green tea on blood glucose levels and serum proteomic patterns in diabetic (db/db) mice and on glucose metabolism in healthy humans. BMC Pharmacology (2004) 4:18:10.1186/1471-2210-4-18

Greenberg, JA, et. al., Coffee, tea and diabetes: the role of weight loss and caffeine. International Journal of Obesity (2005) 29, 1121–1129.

Anderson, RA, et. al., Tea Enhances Insulin Activity. Journal of Agricultural and Food Chemistry (2002) 50(24), 7182-7186.