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Green Tea & Caffeine
Ever since 8th century Buddhist monks
discovered that it could help them stay awake during marathon meditation
sessions, tea has been used to increase energy, brighten the mood and
refresh the mind. The invigorating effects of tea are due to caffeine, a
central nervous system stimulant that fights sleepiness, speeds up the
heart rate, increases alertness, improves athletic
endurance, assists in weight loss and may even heighten intellectual
activity.
Of course, the downside of caffeine is that too
much can make you nervous, irritable, and unable to fall asleep at
night. It can also reduce fine motor coordination and trigger headaches
and dizziness. Most healthy adults can handle 200-250 mg. per day
without adverse effects, but some find that even a small dose makes them
jittery.
The best of both worlds
When it comes to caffeine, green tea may offer the best of both worlds
-- just enough to brighten the mood, but not enough to trigger sleepless
nights. The average cup of green tea contains about 20 mg of caffeine,
while black tea has about 40 mg, and drip coffee packs a nerve-jangling
punch of 90-150 mg. Although some who are sensitive to caffeine may find
that drinking green tea (especially in large amounts) keeps them awake
at night, most people don't have this problem. That may be because
green tea
also contains theanine, an amino acid that functions as a natural
tranquilizer.
Decaffeinated tea
For those who are really serious about
limiting their caffeine, there is always the option of drinking
decaffeinated tea. But beware, as the standard way of decaffeinating tea
(using ethyl acetate) obliterates about 70 percent of green tea’s
catechins. This method involves soaking the tea leaves in a chemical
solvent called ethyl acetate, which binds to the caffeine. Then both the
ethyl acetate and the caffeine are boiled away. Unfortunately, most of
the health-promoting catechins also disappear in the process.
The carbon dioxide method (also
referred to as “effervescence”) is a much gentler, more natural process.
The tea leaves are soaked in liquefied carbon dioxide gas, which binds
to the caffeine and “soaks it out” of the leaves. The liquid and
the caffeine are then poured off (no heating required), leaving about 95
percent of the tea catechins intact.
So if you do decide to drink decaffeinated green
tea, be sure to look for a brand that uses the carbon dioxide or
effervescence method. Otherwise, you may be drinking a brew that’s
essentially devoid of catechins.
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Nadine Taylor, M.S., R.D. presents
GreenTeaLibrary.com,
the most comprehensive collection of scientific information
describing the health benefits of green tea.
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