Green Tea Polyphenols : The Focus of Green Tea Antioxidants

Green tea polyphenols form the bedrock of antioxidants in green tea. Polyphenols is a generic term of phytochemical compounds found in plants, of which flavonoids are a type and a subtype of these flavonoids are the catechins. Most of us may have already heard of antioxidants and even how they work but much less likely with polyphenols, flavonoids and catechins. But these are the terms which seem to be used interchangeably in referring to the primary antioxidants in green tea.

Cathechins : The most potent force of green tea polyphenols

Most of the clinical studies and research carried out on the health benefits of green tea has been heavily focused on the catechins. There are 4 main types of catechins which I list below in order of their level of antioxidant activity.

epigallocatechin gallate (EGCG)

epigallocatechin (EGC)

epicatechin gallate (ECG)

epicatechin (EC)

Research has indicated that it is these green tea polyphenols which are responsible for most of the antioxidant activity of green tea. They are the ones doing most of the heavy lifting in scavenging the free radicals which are the unstable molecules causing oxidation to take place, the internal rust within our bodies. But the spot-light is really on the epigallocatechin gallate (EGCG) as it is found to be the most potent. It was reported that EGCG packed 100 times more power than vitamin C and 25 times the power of vitamin E. And the good news is that EGCG constitutes the highest proportion of catechin content in green tea.

Are we really getting these green tea polyphenols?

All teas be it green, oolong, white or black derive from the same Camellia Sinensis plant and they all contain different levels of these catechins polyphenols. Unlike oolong and black tea which are allowed to oxidize and fermented further, both green tea and white tea because of the way they are harvested and processed contain the highest levels of catechins. So, by drinking green tea especially the top bush of two leaves and a bud, you will be assured of a high content of these green tea polyphenols.

Deccafeinated green tea

Having your green tea decaffeinated may remove some of these polyphenols. But this may only be marginal if the carbon dioxide method is used.

Absorbtion by the body

Are these green tea polyphenols absorbed by our bodies or are they simply discharged in our urine? In the book Flavonoids in Health and Disease edited by Professor Catherine Rice-Evans, it was stated that green tea polyphenols catechins are absorbed mainly in the small intestines and in the case of epigallocatechin gallate (EGCG) absorbtion can take place as early as in the mouth.

Extracts of green tea polyphenols

The potency of green tea polyphenols has gained so much acclaim that it is now available in the form of extracts. Such green tea extracts are usually standardized to a certain percentage of the polyphenols and the EGCG such as 95% polyphenols and 75% EGCG. Such percentages might be even lower still. Many of the clinical studies and researches on the health benefits of green tea are carried out using these green tea polyphenol extracts. Green tea extracts are also used to make dietary green tea supplements which are available in the form of pills, capsules and even patches.

Green tea supplements in the form of these extracts are to be used only in moderation. There are now reports of adverse side effects of taking concentrated green tea extracts such as liver damage. But such reports seem to be associated only with the extracts rather than the beverage itself.

Green tea polyphenols and the other constituents

It is a curious wonder why we have negative reports on green tea extracts but seemingly not from drinking green tea itself. It seems that too much emphasis have been placed on green tea polyphenols in its antioxidant and health giving capacity whilst ignoring the other constituents such as the green tea vitamins, minerals and amino acids. There is some merit in the argument that the full potentcy of the antioxidants in green tea can only be had from the synergistic combination or interaction of all its components or ingredients.

The synergistic interaction between caffeine and the amino acid theanine may lend some support to this line of argument. In drinking green tea as opposed to coffee for example, before the side effects of caffeine could rear its ugly heads, it is somewhat neutralized by the calming effect of theanine which is an amino acid found only in green tea. Would it seem too far-fetched then to ask who knows any possible effects of a high polyphenol content might be counter-balanced by the other ingredients in green tea?

In traditional Eastern medicine there is such a thing as the ying yang balance in food and that we should be consuming foods the way Mother Nature has intended : not just taking a part and throwing away the rest. Of course, there is no way to prove this Eastern philosophy and is not widely acknowledged in Western medicine. But we can also draw another parallel : the PH balance in foods, the acid/alkaline balance which is a much more established principle in nutritional science.

But all this is a matter of conjecture. For, after all science has yet to fully understand the numerous substances found in green tea, let alone how they work together in its antioxidant activity. Suffice to say that it is much safer to drink green tea. This way you can avail yourself of the full spectrum of green tea antioxidants.

Filed under: Green Tea Antioxidants

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