Green tea may help protect against autoimmune disease,
Medical College of Georgia researchers say.
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
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
"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," he says.
There is no cure or
prevention for Sjogren's Syndrome.
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.
already know that one component of green tea – EGCG – helps
suppress inflammation, according to Dr. Hsu.
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."
published in a recent issue of Autoimmunity, reinforced
findings of a 2005 study showing a similar phenomenon in a
Petrie dish, Dr. Hsu says.
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 inflammation.
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."
study could help determine green tea's protective role in
other autoimmune diseases, including lupus, psoriasis,
scleroderma and rheumatoid arthritis, he says.