The findings are based on a study, in which researchers tested the effect of green tea's predominant antioxidant, EGCG, in a laboratory mouse with type 1 diabetes and primary Sjogren's syndrome, which damages moisture-producing glands, causing dry mouth and eyes.
"Our study focused on Sjogren's syndrome, so learning that EGCG also can prevent and delay insulin-dependent type 1 diabetes was a big surprise," says Dr. Stephen Hsu, molecular/cell biologist in the School of Dentistry.
In the mouse, EGCG reduced the severity and delayed onset of salivary gland damage associated with Sjogren's syndrome, which has no known cure.
"EGCG modulates several important genes, so it suppresses the abnormality at the molecular level in the salivary gland. It also significantly lowered the serum autoantibodies, reducing the severity of Sjogren's syndrome-like symptoms," Dr. Hsu said.
Both type 1 diabetes and Sjogren's syndrome are autoimmune diseases, which cause the body to attack itself.
The study backs previous research showing EGCG's impact on helping prevent autoimmune disease.
In the current study, researchers treated a control group of mice with water and a test group with a purified form of EGCG dissolved in the drinking water.
At 16 weeks, the EGCG-fed mice were 6.1 times more likely to be diabetes-free than the water-fed group, and 4.2 times more likely at 22 weeks.
"Our study is significant because we used a mouse model with the genetic defects that cause symptoms similar to human type 1 diabetes and Sjogren's syndrome, so the immune cells attack the pancreas and salivary glands until they are no longer functional," Dr. Hsu said.
The next step is to observe Sjogren's syndrome in human salivary gland samples to determine whether the study findings hold up in humans.
"If the abnormal expression of these genes is the same in humans as in the animal model, then the second stage will be intervention and treatment with a pure form of EGCG," says Dr. Hsu.
Dr. Gillespie, periodontics chief resident at Fort Gordon's Tingay Dental Clinic, said: "The benefit of using green tea in preventing or slowing these autoimmune diseases is that it's natural and not known to harm the body.
EGCG doesn't have the negative side-effects that can be associated with steroids or other medications that could otherwise be prescribed."
The study is published in the Oct. 24 issue of Life Sciences.