Green Tea for Allergies by Food Navigator.com
New evidence suggests that drinking the increasingly popular
green tea may provide some relief to allergy sufferers.
Researchers in Japan identified a compound in green tea that, in
laboratory tests, blocks a key cell receptor involved in producing
an allergic response. The compound, methylated epigallocatechin
gallate (EGCG), may have a similar effect in humans, they said.
The study will be published in the 9 October issue of the
Journal of Agricultural and Food Chemistry, the American
Chemical Society publication.
Although similar compounds in green tea have previously been
shown to be anti-allergenic, this particular compound appears to be
the most potent, the researchers said.
"Green tea appears to be a promising source for effective
anti-allergenic agents," said Hirofumi Tachibana, the study's
chief investigator and an associate professor of chemistry at
Kyushu University in Fukuoka, Japan. "If you have allergies,
you should consider drinking it."
People have long been drinking tea to fight the sneezing,
coughing and watery eyes that are characteristic of colds and
allergies. The new study adds to a small but growing body of
scientific evidence from both cell and animal studies that it may
actually work, particularly green tea.
No one has proven, however, that anti-allergenic compounds found
so far have a therapeutic effect in humans who ingest green tea.
But if it works, the brew may be useful against a wide range of
allergens, including pollen, dust, pet dander and certain
chemicals, Tachibana said. There are currently 50 million people in
the US suffering from allergies however the researchers noted that
further studies are needed.
EGCG is one of the most abundant and biologically active
antioxidants found in tea. It is believed to be responsible for
tea's beneficial health effects. The compound is found in higher
concentrations in green tea, the least processed of teas, than in
black and oolong varieties.
Previous studies have shown that EGCG fights allergic reactions
in rodents that were given the compound orally, but researchers are
just beginning to understand how it might work.
It now appears that the compound works by blocking the
production of histamine and immunoglobulin E (IgE), two compounds
in the body that are chiefly involved in triggering and sustaining
allergic reactions, Tachibana explained.
The current study shows for the first time that a methylated
form of EGCG can block the IgE receptor, which is a key receptor
involved in an allergic response. The effect was demonstrated using
human basophils, blood cells that release histamine.
Methylated EGCG appears to elicit a stronger anti-allergenic
response than normal EGCG, making it the strongest anti-allergen
compound found in tea, according to the researchers.
Although promising against allergies no one knows how much green
tea is needed to have a therapeutic effect, or which green tea
varieties work best, the researchers added. They are currently
looking for additional anti-allergenic compounds in the tea.
Green tea has been called the second-most consumed beverage in
the world, behind water. Already very popular in Japan, it has a
growing following in the United States, where black tea has
traditionally been favoured. Tachibana's study adds to an expanding
list of the potential health benefits offered by green tea. In
addition to allergies, it is reported to fight cancer,
cardiovascular disease, arthritis and tooth decay.
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