Tea is one of the oldest drinks (used
for almost 50 centuries in Asia) and – after water – the most common
beverage people enjoy the world over (Mandel et al. 2008). Native to
China, it comes from the evergreen plantCamellia sinensis. A cup
of tea contains numerous compounds in varying quantities: vitamins,
polyphenols, caffeine, fluoride, sugars, amino acids, proteins,
minerals, chlorophyll and others (Zhao et al. 2013). Which tea is
produced (white, green, oolong or black) depends on the subsequent
processing of harvested Camellia leaves. Teas can be classified as non-fermented (green and white teas), semi-fermented (oolong tea), and fermented (black tea).
The health promoting effects of green tea are
attributed to the rich antioxidant polyphenol content of its leaves
(flavonols & catechins), making up c. 30% dry weight of a tea leaf,
and exhibiting biochemical and pharmacological activities (Siddiqui et
al. 2006). Recently, many of these beneficial effects were traced back
to the most abundant catechin, EGCG (Wolfram 2007).
White tea differs from green tea by only using
buds or first leaves. Green tea is rich in catechins. Black tea
contains high levels of bisflavanol, theaflavin, and thearubigin,
whereas white tea possesses large amounts of epigallocatechin-3-gallate
or EGCG, epicatechin, and methylxanthine (Zhao et al. 2013).
And just like a good wine,
geographic location, soil and growing conditions play a role in tea
quality, too. Tea leaves are heated and dried to inactivate enzymes,
thus preserving constituents until we come along to make a brew by
simply adding hot water.
The convenience of tea bags comes for the price of
much reduced quality: tea bags usually contain shredded bits of tea
hardly deserving the name. I generally avoid tea bags. Loose leaf tea
just tastes so much better. As a rule of thumb, the bigger the leaf, the
better and more tasty the tea. Tea bags either contain chemicals
(epichlorohydrin) to prevent the paper from disintegrating in water, or
are made from plastic including potentially harmful substances. Both are
not the best choice. No need to ingest anything that doesn’t naturally
belong in the body. Exercising that control whenever you have it makes
not only sense, but also for a much healthier body.
Three billion kilograms of tea are grown and
processed worldwide annually (Ohsaki Study 2006). People in about 30
countries are the main tea consumers. Green tea, specifically, is most
commonly used in Asia (c. 20%), whereas Westerners prefer black tea (c.