What's
in Tea?
Tea contains a small amount of necessary vitamins
as well as mineral elements such as manganese,
zinc, potassium and magnesium. It contributes
in a small way to the intake of these and complements
the main source of these vitamins and minerals
obtained from other foods in a balanced diet.
Tea provides a small natural source of fluoride,
but again does not provide enough to prevent tooth
decay, although its lack of sugar does help towards
keeping teeth healthy.
Tea has no carbohydrates or fat if served without
milk or sugar, and is calorie-free so it makes
an ideal beverage for the figure conscious. Research
has identified some important pharmacological
constituents in tea. These are caffeine, theophyline
and theobromine.
- Caffeine stimulates the central nervous system
and respiration. It influences the metabolic
processes of all body cells.
- The average cup of tea contains approximately
40 milligrams of caffeine, which is half the
amount contained in an average cup of coffee.
When tea is drunk, the caffeine is absorbed
gradually into the body. The body will only
absorb its natural requirements, so that the
rest of the caffeine will be washed out of the
system by the diuretic effects of tea. The comforting
quality of the warm tea is felt at once, whereas
the gradual absorption of the required amount
of caffeine giving that "uplift" or
stimulus to the mind and body, is slower and
less perceptible but is there just the same.
- Theophylline and theobromine have similar
but milder effects to caffeine. They stimulate
the central nervous system and respiration and
help muscle relaxation. In larger doses they
promote diureses, the natural waste disposal
system of the body; they aid coronary artery
dilation thus very gently stimulating the heart
and helping blood circulation. This is one reason
why people who have suffered a severe shock
are often given hot tea to drink as a means
of calming them and also stimulating them.
- Finally, tea contains polyphenois, erroneously
called tannin by the tea trade. These are responsible
for the pungency of tea and give it its taste.
However, polyphenois should not be confused
with tannin as obtained from tree bark.
If you over in-fuse or over-brew your tea the
proportion of polyphenois to caffeine, theophylline
and theobromine which dissolve in the infusion
is upset. This will produce a bitter and strongly
astringent tasting tea and although unpleasant
to taste, it will not cause you any harm.
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