Green tea helps protect against autoimmune disease

20/06/05 Green tea seems to help protect the body from autoimmune disorders, according to a Medical College of Georgia oral biologist. Dr. Stephen Hsu, a researcher in the MCG School of Dentistry, has amassed a large bank of research helping document green tea's health benefits in everything from oral cancer to wrinkles. The benefits spring from compounds in green tea called polyphenols, which help eliminate DNA-damaging free radicals. As an added benefit, a green tea-induced protein called p57 protects healthy cells as polyphenols target cancer cells for destruction.

Dr. Hsu's most recent findings, which he will present June 17-20 in Atlanta at the Arthritis Foundation's fifth biennial Arthritis Research Conference, target autoimmune diseases. These diseases, such as type 1 diabetes, rheumatoid arthritis, lupus and Sjogren's disease, inexplicably prime the body's immune system to attack its own tissues, with often disabling and even life-threatening consequences. Adverse effects often accompany autoimmune disease treatment, which mainly focuses on the immune system.

One autoimmune disorder-the immune system's destruction of glandular cells-causes dry mouth, or xerostamia. Dry mouth occurs in about 30 percent of elderly Americans, but only in 1 percent to 2 percent of Chinese seniors. It is one of many health disparities that Dr. Hsu suspected was linked to Asians' frequent consumption of green tea.

Dr. Hsu is probing green tea's role in producing autoantigens. Autoantigens are normal molecules in the body with useful functions, but changes in their amount or location can trigger an immune response. "I wanted to know how green tea polyphenols affect the production of autoantigens," Dr. Hsu said.

He suspected a link because a polyphenol called EGCG is known to suppress inflammation, which results when the immune system mounts a defense to a real or perceived enemy. "If EGCG suppresses inflammation, it should affect the magnitude of the autoimmune response, possibly by suppressing autoantigens," Dr. Hsu said.

The Medical College of Georgia is the state's health sciences university and includes the Schools of Allied Health Sciences, Dentistry, Graduate Studies, Medicine and Nursing.