According to the Centers for Disease Control and Prevention, millions of Americans suffer from some form of a kidney disorder that can be embarrassing, painful or even life threatening. For centuries, folk medicine practitioners in Asia have used green and black tea to treat a variety of conditions, including kidney disease. Modern research shows that tea's benefits come from high levels of antioxidants called "polyphenols," compounds that fight free radical damage to cells in your kidneys and throughout your body.
Tea and Diabetic Kidney Disease
If you have diabetes, you are at a higher risk for several health complications, including kidney failure. A study on rats study published in May 2004 in the "Annals of Nutrition and Metabolism" investigated green tea antioxidants on kidney damage in diabetic rats. The researchers found that a cellular waste product caused by free radical damage was close to 150 percent greater in the diabetic rats that did not receive green tea extracts to those that did.
Tea and Kidney Cancer
A follow-up study of patients enrolled in 13 studies involving 800,000 investigated whether there were associations between coffee, tea, milk, soda or juice consumption and renal cell cancer of the kidneys. Published in the "International Journal of Cancer" in November 2007, the study discovered that coffee and tea consumption might be associated with a modestly lower risk of renal cell cancer. This is far from a cure. If you have kidney cancer, consult your doctor first before drinking tea or taking tea supplements.
Tea and Immunosuppressants
An animal study published in "Pharmacological Research" in January 2005 found that giving rats green tea prevented kidney dysfunction after taking the type of immunosuppressant drugs a human organ transplant patient must take to avoid your body rejecting the new organ. Green tea also may improve several of your other markers for healthy kidney function, including creatinine levels, blood urea nitrogen, uric acid and excretion of glucose.
Tea and Kidney Stones
A kidney stone is an often-painful, solid mass composed of tiny crystals that forms in your kidney due to infection, dehydration or nutritional imbalances. Two separate studies investigated the potential benefits of tea in preventing stone formation, one in women and the other in men. The study on women, part of the 81,093 subjects in the long-term Nurses' Health Study, reported in the "Annals of Internal Medicine" in 1998 that tea drinking decreased the risk for kidney stones by 8 percent. The study on men, published in the "American Journal of Epidemiology" in 1996, involved 45,289 men and found tea drinkers in the group had a 16 percent reduced risk of forming stones.
- University of Maryland Medical Center: Green Tea; September 2010
- National Kidney and Urologic Diseases Information Clearinghouse: The Kidneys and How They Work; September 2010
- "Pharmacology Research"; Green Tea Extract Attenuates Cyclosporine A-Induced Oxidative Stress in Rats; A.M. Mohammadin, et al.; January 2005
- "Annals of Nutrition and Metabolism"; Effects of Green Tea Catechin on Polymorphonuclear Leukocyte 5′-Lipoxygenase Activity, Leukotriene B4 Synthesis and Renal Damage in Diabetic Rats; Jeong-Hwa Choia; 2004
- "Annals of Internal Medicine"; Beverage Use and Risk for Kidney Stones in Women; G.C. Curhan, et al.; April 1998
- "American Journal of Epidemiology"; Prospective study of beverage use and the risk of kidney stones; G.C. Curhan, et al.; February 1996