New Study Shows Tea (L-Theanine) Boosts the Body's Defenses by ImmuneSupport.com
A new study finds that tea boosts the body's defenses against
infection and contains a substance that might be turned into a drug
to protect against disease, researchers say. Coffee does not have
the same effect, they say. A component in tea was found in
laboratory experiments to prime the immune system to attack
invading bacteria, viruses and fungi, according to a study in the
Proceedings of the National Academy of Sciences released
A second experiment, using human volunteers, showed that immune
system blood cells from tea drinkers responded five times faster to
germs than did the blood cells of coffee drinkers.
"We worked out the molecular aspects of this tea component in
the test tube and then tested it on a small number of people to see
if it actually worked in human beings," said Dr. Jack F. Bukowski,
a researcher at Brigham and Women's Hospital in Boston and Harvard
Medical School. The results, he said, gave clear proof that five
cups of tea a day sharpened the body's disease defenses.
Penny Kris-Etherton, a nutrition specialist at Penn State
University, a nutrition expert, said Bukowski's study adds to a
growing body of evidence that tea is an effective disease
"This is potentially a very significant finding," she said.
"We're seeing multiple benefits from tea."
But she said the work needs to be confirmed in a much larger
study, involving more people.
In the study, Bukowski and his co-authors isolated from ordinary
black tea a substance called L-theanine.
Bukowski said L-theanine is broken down in the liver to
ethylamine, a molecule that primes the response of an immune system
element called the gamma-delta T cell.
"We know from other studies that these gamma-delta T cells in
the blood are the first line of defense against many types of
bacteria, viral, fungal and parasitic infections," he said. "They
even have some anti-tumor activity."
The T cells prompt the secretion of interferon, a key part of
the body's chemical defense against infection, Bukowski said.
"We know from mouse studies that if you boost this part of the
immune system it can protect against infection," he said.
To further test the finding, the researchers had 11 volunteers
drink five cups a day of tea, and 10 others drink coffee. Before
the test began, they drew blood samples from all 21 test
After four weeks, they took more blood from the tea drinkers and
then exposed that blood to the bacteria called E-coli. Bukowski
said the immune cells in the specimens secreted five times more
interferon than did blood cells from the same subjects before the
weeks of tea drinking. Blood tests and bacteria challenges showed
there was no change in the interferon levels of the coffee
drinkers, he said.
Bukowski said it may be possible to further isolate and refine
L-theanine from tea and use that as a drug to boost the infection
defense of the body.
The health effects of tea have been extensively studied. It has
been linked to lower heart disease and cancer risk through the
action of flavonoids, a type of antioxidant. Other studies have
linked tea to helping combat osteoporosis, the brittle bone
disease, and to relieving some allergy symptoms.
Proceedings of the National Academy of Sciences:
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