Whilst increasing attention is now rightly being paid to the health benefits of white and green teas, the virtues of the much more familiar, and still much more common, black tea, should not be neglected. All three are products of the camellia sinensis plant and as such have many common attributes, particularly in their anti-oxidant functions; the difference between them being entirely attributable to the differing methods by which they are produced.
So-called "herbal teas", by contrast, are drinks made from infusions of the leaves of a wide variety of other plants. Although these are often very beneficial to health, they are not "teas" at all in the strict sense, this term being restricted to the products of the camellia sinenis plant, and should be considered separately, probably as a branch of herbal medicine or therapy.
The fresh, ie unprocessed, leaves of the camellia sinensis plant are rich in compounds known as polyphenols, and particularly those of a type known as catechins, which are powerful anti-oxidants. The problem is that these compounds are easily destroyed by the processing that the leaves go through. In the case of black teas the process, known as fermentation, results in the almost complete oxidation of the catechins resulting in a dramatic loss of their anti-oxidant power.
The highly prized white teas, by contrast, are produced by steaming the very young leaves of the camellia sinensis plant, protecting them from this damaging oxidation. Green teas are produced by a similar process of heat treatment, but the older leaves used are not generally as rich in the active ant-oxidant compounds. There is yet another category of teas, known as oolong, which fall somewhere between the green and black varieties by being partially oxidised (fermented).
Whilst conventional medicine continues to insist that the evidence for the health giving benefits of all these teas remains inconclusive, there is in fact ample evidence of the anti-oxidant power of these beverages. For example, a number of respectable studies have concluded that moderate tea consumption (just a few cups day) may reduce the risk of heart disease by around a third, in the case of black tea, and a half in the case of green tea. At least one research report further suggests that tea consumption may help reduce the risk of stroke by as much as two-thirds.
Since heart disease and stroke remain two of the biggest causes of premature death and disability in the affluent Western world, these findings alone would seem to make the regular consumption of tea, and green tea in particular, a worthwhile precaution.
Source : articlesbase
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