Green Tea
Helps Prevent Rheumatoid Arthritis
Contact George Stamatis, 216-368-3635 or gxs18@po.cwru.edu
Antioxidants in green tea may prevent and reduce the severity of rheumatoid
arthritis, according to a study from Case Western Reserve University's School of
Medicine published in the "Proceedings of the National Academy of
Sciences."
The study examined the effects of green tea polyphenols on collagen-induced
arthritis in mice, which is similar to rheumatoid arthritis in humans.
Polyphenols are chemicals that occur naturally in certain foods, including green
tea, and many work as antioxidants to protect the body from oxidative stress
that causes disease.
In each of three different study groups, the mice given the green tea
polyphenols were significantly less likely to develop arthritis. Of the 18 mice
that received the green tea, only eight (44 percent) developed arthritis. Among
the 18 mice that did not receive the green tea, all but one (94 percent)
developed arthritis. In addition, researchers noted that the eight arthritic
mice that received the green tea polyphenols developed less severe forms of
arthritis.
"For many generations, in some parts of the world -- including India, China
and Japan -- green tea has been considered to possess health-promoting potential
by preventing many illnesses that cause substantial mortality and morbidity in
humans," said lead author Tariq M. Haqqi, associate professor of medicine
at CWRU.
"Extensive laboratory research and the epidemiologic findings of the last
15 years have revealed that polyphenolic compounds present in green tea may
prevent the onset and subsequent progression of a variety of illnesses. Perhaps
now arthritis can be added to the list."
Tea is one of the most commonly consumed beverages in the world, second only to
water. However, only 20 percent of the tea consumed worldwide is green tea. The
remainder is black tea.
"Many polyphenols in green tea possess much more potent antioxidant
activity than well-known antioxidants such as vitamin C and vitamin E,"
said Haqqi.
Although there is no epidemiologic data, anecdotal evidence indicates that
people in countries where green tea is consumed are far less likely to have
rheumatoid arthritis, said the study's senior author, Hasan Mukhtar, professor
of dermatology.
In the United States, however, this debilitating disease has been diagnosed in
more than 2 million people. Extensive research, pioneered at CWRU School of
Medicine during the past decade, has shown that antioxidants present in green
tea possess cancer-preventing and anti-inflammatory properties.
Rheumatoid arthritis is an inflammatory disease that causes pain, swelling,
stiffness and loss of function in the joints. There is no cure for the disease.
Instead, physicians control the symptoms of rheumatoid arthritis with pain
relievers and anti-inflammatory medications, which in turn slow the damage to
the joints.
"The study suggests a preventive approach to rheumatoid arthritis. A slight
modification in your lifestyle -- adding green tea to your diet -- could reduce
your risk of this disease," said Mukhtar. "The extract given to the
mice was the equivalent of a human drinking four cups of green tea a day."
In three independent experiments, six mice received water with green tea
polyphenols, while six others received plain drinking water. All of the mice
then were injected with collagen to induce arthritis and were studied for 40
days. One group was examined for a total of 85 days to ensure that the green tea
compound was not merely delaying the onset of the disease.
In the first experiment, two of the six mice given green tea polyphenols and all
six of the mice given plain water developed arthritis. In the second experiment,
three of six in the green tea subset and again all six in the water group had
arthritis. The incidence of arthritis in the third experiment was three of six
in the green tea group and five of six among the other mice.
The study also shows the mice that developed arthritis despite receiving green
tea polyphenols had a less severe form of arthritis.
"This study, in the most widely used and accepted animal model system that
closely mimics the human disease, clearly shows that mice given green tea
polyphenols in water were significantly protected from the development of
arthritis, and, if they did develop the disease, its severity was mild,"
Haqqi concluded.
The article is available on the journal's Web site at http://www.pnas.org/cgi/content/abstract/96/8/4524.
The Arthritis Foundation funded the research. For more information about the
foundation or information about managing arthritis, call 1-800-283-7800.
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