Green tea's possible protection against autoimmune disorders

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Research: Green Tea's Protective Role in Autoimmune Disease

ProHealthNetwork.com

 

06-20-2005

 

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, presented 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.

 

To test the theory, Dr. Hsu studied cells in salivary glands and

skin tissue. Cells exposed to green tea showed RNA and protein

levels indicating autoantigen levels were suppressed in these normal

cells, but not in tumor cells. " We were so shocked, " Dr. Hsu said of

the finding that further highlighted green tea's role in attacking

tumor cells while protecting healthy cells.

 

And because of the low levels of autoantigens in healthy cells, " the

immune system now has considerably fewer targets to potentially

attack, " greatly reducing the risk of autoimmune disease, Dr. Hsu

said.

 

Dr. Hsu, who has applied for two $1 million U.S. Department of

Defense grants and a $1.25 million National Institutes of Health

grant to further his research, has extended his studies to animal

models. He is studying two sets of mice, both programmed to develop

autoimmune disease. He is observing one set as the disease follows

its natural course. " This model should develop diabetes, dry mouth

and dry eyes within 12 to 30 weeks, then die quickly, " Dr. Hsu said.

 

The other set began drinking green tea at age 3 weeks, immediately

after weaning. He is anxious to determine whether green tea delays

the onset of autoimmune disease or otherwise affects its course. Dr.

Hsu, who has helped incorporate green tea polyphenols into everyday

products such as gum and skin cream, hopes his latest research will

ultimately yield a wealth of findings that can help scientists

better understand and treat autoimmune disease.

 

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. MCG is a unit of

the University System of Georgia and an equal opportunity

institution. http://www.mcg.edu