The Hidden Health Benefits of Tea by Food Today
In Food Today 15, we looked at some of the potential health
benefits of phyto-protectants and plant nutrients present in
fruits, vegetables, cereals and beverages. Most of these substances
are capable of protecting plants from the stresses and strains of
their environment. Now research is showing that we too can get
these benefits when including these foods in our diets.
Tea is probably one of the most surprising sources of helpful
plant nutrients. With the exception of water, tea is the most
widely consumed beverage in the world. Green tea is made from the
fresh leaves of the tea plant that are steamed, rolled and dried at
high temperatures. Black tea is made by first withering the leaves
and then rolling and drying them.
The familiarity of a cup of tea makes it hard to imagine that
hidden away inside every sip are substances capable of bolstering
our bodies defences to help fight chronic diseases such as heart
disease or cancer.
The plant nutrients in tea that have fired the enthusiasm of
researchers are called flavonoids. Thousands of flavonoids are
distributed throughout the plant world and many have antioxidant
functions. This means they are capable of mopping up and
deactivating potentially harmful free radicals which, if left to
roam the body, may spark chronic health problems such as
cardio-vascular diseases, cancer, cataracts, inflammation,
arthritis and even Alzheimer's disease. For example evidence from a
study in Holland (1) has indicated that people with a measurably
higher flavonoid intake have a reduced risk of heart disease
compared with those who consume less.
Just one cup of tea supplies around 200mg of flavonoids, many of
which are released into the drink within the first minute of
brewing. However, shorter brewing time leads to lower flavonoid
levels. Having three cups a day over 2 weeks increases the
concentration of flavonoids in the blood by 25% and fortunately,
its antioxidant effects are not affected by adding milk (2).
Drunk daily throughout the world for centuries, Chinese
herbalists have long revered the healing properties of tea,
recommending it for a wide variety of ailments ranging from
clearing the voice to aiding digestion and relieving water
retention. Today, the health benefits seem to be getting the seal
of approval from scientists in the west.
What's in a Cup of Tea?
Substance Special points Catechins: Over half of the total
catechin content is epigallocatechin gallate which is also known as
EGCG. It is 20 times more powerful than vitamin C as an
antioxidant. Thearubigins A complex flavonoid that develops when
leaves of tea are fermented and turn black. Theaflavins Also
produced during fermentation of the leaves. Caffeine Mild stimulant
found in tea, a 200ml cup contains an average of 40mg of caffeine
compared to 64mg in instant coffee and up to 150mg in brewed
coffee. Tannin A type of flavonoid that adds flavour, astringency
and bitterness to tea, in addition to its antioxidant
Back to Health
Hertog, M.G.L, Kromhout, D., Aravanis, C. et al. (1995) Flavonoid
intake and long-term risk of coronary heart disease and cancer in
Seven Countries Study. Arch Intern Med 155: 381 - 386 Van het Hof,
H.H., Kivits, G.A.A., Westrate, J.A. and Tijburg, L.B.M. (1988)
Bioavailability of catechins from tea: the effect of milk. Eur J
Clin Nutr 52:356 - 359