|
 ntioxidants 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. 
|
