Green Tea May Help
Prevent Autoimmune Diseases
Green tea may help protect against autoimmune disease,
Medical College of Georgia researchers say.
Researchers studied an animal model for type
I diabetes and primary Sjogren's Syndrome, which damages
the glands that produce tears and saliva.
They found significantly less salivary gland
damage in a group treated with green tea extract, suggesting a
reduction of the Sjogren's symptom commonly referred to as dry
mouth. Dry mouth can also be caused by certain drugs,
radiation and other diseases.
Approximately 30 percent of elderly Americans
suffer from degrees of dry mouth, says Dr. Stephen Hsu, a researcher
in the MCG School of Dentistry and lead investigator on the study.
Only 5 percent of the elderly in China, where green
tea is widely consumed, suffer from the problem.
"Since it is an autoimmune disease, Sjogren's
Syndrome causes the body to attack itself and produce extra
antibodies that mistakenly target the salivary and lacrimal glands,"
There is no cure or prevention for Sjogren's
Researchers studied the salivary glands of
the water-consuming group and a green tea extract-consuming group
to look for inflammation and the number of lymphocytes,
a type of white blood cells that gather at sites of inflammation
to fend off foreign cells.
The group treated with green tea had significantly
fewer lymphocytes, Dr. Hsu says. Their blood also showed
lower levels of autoantibodies, protein weapons produced when
the immune system attacks itself, he says.
Researchers already know that one component
of green tea - EGCG - helps suppress inflammation, according to
"So, we suspected that green tea would
suppress the inflammatory response of this disease. Those treated
with the green tea extract beginning at three weeks, showed
significantly less damage to those glands over time."
These results, published in a recent issue
of Autoimmunity, reinforced findings of a 2005
study showing a similar phenomenon in a Petrie dish, Dr. Hsu
Researchers also suspect that the EGCG in
green tea can turn on the body's defense system against TNF-alpha
- a group of proteins and molecules involved in systemic
TNF-alpha, which is produced by white blood
cells, can reach out to target and kill cells.
"The salivary gland cells treated with EGCG
had much fewer signs of cell death caused by TNF-alpha," Dr. Hsu
says. "We don't yet know exactly how EGCG makes that happen. That
will require further study. In some ways, this study gives
us more questions than answers."
Further study could help determine green tea's
protective role in other autoimmune diseases, including lupus,
psoriasis, scleroderma and rheumatoid arthritis, he says.