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Green Tea Vitamins And Their Antioxidant Functions

I can still remember that as children we were often exhorted to eat those leafy greens and fruits for the vitamins they contain : carrots for vitamin A, oranges for vitamin C, brocolli for Vitamin E, to name a few. But hardly, if ever, was green tea vitamins ever mentioned. Quite apart from the question whether green tea is suitable for children, even today, if you search online, you will notice that green tea is not listed as a primary source of vitamins.

The meaning of green tea vitamins

It has, therefore, daunted upon me that the term green tea vitamins might be loosely used to refer to green tea antioxidants or green tea polyphenols rather than the types of vitamins contained in green tea. So if you have that meaning in mind, you may like to read my related articles in this category.

In this article the latter meaning is used and the main focus is their functions as antioxidants and how they work synergistically with the polyhenols catechins .This will be more in line with the theme of this green tea antioxidants category of this blog. Again, I must state that I am not a nutritionist and what I write is for information purposes only. You should consult your health care provider as regards your own nutritional needs.

The green tea vitamins

We have seen in my article on green tea polyphenols the emphasis placed on the polyphenols catechins, a class of flavonoids, as evidenced by their composition in green tea extracts. So, although green tea vitamins may seem somewhat sidelined in discussions about the antioxidant activities of green tea, they are by no means any less important. Being classified as either water or fat soluble, the vitamins interact synergistically not only amongst themselves but also with the polyphenol catechins which are water-soluble antioxidants.

Briefly, just to recap on what antioxidants do. They quench the free radicals which are the unstable molecules by donating that much needed electron. Free radicals are formed through a process called oxidation just like rusts appearing on metals. Scientific studies have suggested that free radicals could cause damage to cells and over time lead to diseases such as heart disease and cancer.

Vitamin A

Vitamin A is especially essential for having good eyesight. But as an antioxidant, it is not as well established as Vitamins C and E. When obtained from fruits and vegetables or plants, it is in the form of a compound known as beta-carotene which can be converted into vitamin A in our bodies. It is also important for healthy skin.

Vitamin B2

The most important role of Vitamin B2 (riboflavin) is to help the body to metabolize fats, proteins and carbohydrates. Just like Vitamin A, it is also not well know for its antioxidant properties as such.

Vitamin C

Vitamin C (ascobic acid) is a well-known powerful antioxidant. It is essential for the repairing of tissues throughout our bodies. As a water-soluble vitamin, it seems to be more ‘specialized’ in its work as an antioxidant in those watery surroundings within out bodies such as within the cells themselves. According to Prof. Balz Frei of the Linus Pauling Institute, in his question and answer session, Vitamin C is capable of interacting with and regenerating Vitamin E which is a fat-soluble vitamin. He also said that although Vitamin C might not have the antioxidant capacity of the flavonoids, it is more reactive in scavenging the free radicals.

Also, a preliminary study conducted by Prof. Mario Ferruzzi and his team of researchers at Purdue University suggested that Vitamin C might help in the absorbtion of polyphenols catechins. Further research will need be carried out on human subjects.

Vitamin E

This is another potent antioxidant. Being a fat-soluble vitamin, it is more ‘specialized’ in protecting the fatty acids in the cell membrane from oxidation. An interesting point in this connection is the possible synergistic interaction between vitamin E and the polyphenol catechins specifically the egcg in preventing the arteries from being clogged.

Vitamin E being a fat soluble vitamin is more suited to the task of preventing the oxidization of the bad cholesterol known as LHL cholesterol which is predominantly fats. When LHL cholesterol is oxidized, it begins to stick to the wall of the arteries and form plaque leading to a condition called atherosclerosis. This in effect narrows the arteries and restricts the supply of blood to all parts of the body which may result in a heart attack or stroke.

This task of guarding the LHL cholesterol from oxidation takes a heavy toll on Vitamin E. Although Vitamin E can be regenerated by Vitamin C, studies conducted by Prof. Catherine Rice-Evans of King’s College London suggests the possibility of the polyphenol cathchins indirectly safeguarding the LHL cholesterol from oxidation and thus preventing the depletion of Vitamin E. Polyphenol catechin being a water-soluble antioxidant which dissolves only in water (but not in fats) does not work in a fats surroundings like inside a LHL molecule. But, operating from a watery surroundings outside of the LHL molecule, it is possible that the polyphenols catechins may intercept or scavenge and quench these free radicals before they can even get to the LHL cholesterols.

Vitamin K

The main function of vitamin K is blood clotting and the building of bone mass. Not a well known antioxidant but research indicates that being a fat-soluble vitamin it interacts with Vitamin E in scavenging free radicals in the cell membrane particularly protecting linoleic acid which is an essential omega 6 fatty acid for our good health.

It is quite unlikely that green tea will often be cited as a significant source of vitamins. At any rate, vitamins are commonly found in the wide spectrum of fresh fruits and vegetables and generally for most of us we can have an adequate supply by eating a balanced diet. What makes green tea stand out in its health benefits is its peculiar combination of catechins polyphenols working together with the green tea vitamins. This article serves to inform the types of vitamins that could be found in green tea and their synergistic interaction with the other antioxidant compounds. We are merely scratching the surface here and research continues unabated in unraveling the properties in green tea. It is hoped that this together with the related articles in this category go to show to some extent how complete the camellia sinensis tea plant is as a significant source of antioxidants. The next time when you are brewing your tea, just be mindful that it’s a healthy drink you are preparing.

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.

Green Tea Antioxidants – A Powerhouse of Antioxidants

Where green tea antioxidants are concerned, green tea is a class unto itself. Often listed as one of the top 10 antioxidant foods, green tea is in the elite company of fresh fruits and vegetables such as berries, broccoli, carrots and tomatoes, just to name a few. Yet, it has often been claimed that in fact green tea packs even more antioxidant power than most of these healthy foods.

Although this site is primarily a guide to drinking green tea, I have decided to deal at some length on this subject of green tea antioxidants so that each time you drink this wonderful beverage you’ll be able to appreciate it even more. Besides, I know of some people whose foremost reason for drinking green tea is for its health benefits. But I am not a nutritionist and what I write here is for information purposes only. It would be best for you to consult your health care provider about your own nutritional needs.

The content of antioxidants in green tea

Antioxidants are found in all teas be they green, white, black or oolong which derive from the same camellia sinensis tea plant. Because of the way they are processed to stop the oxidation, both green and white tea have the highest content of antioxidants. And in green tea itself, the highest content of antioxidants are found in the first flush. Since most of the Chinese green teas are harvested only once a year in the spring, they are necessarily of the first flush. The Japanese sencha can be either of the first or second flush. Gyokuro, although of the first flush are shaded from direct sunlight before the harvest which to some extent actually reduce the level of its antioxidants. But Matcha, although derived from gyokuro, has a high content of the antioxidants, for then you will be consuming the tea leaves as a whole in powdered form.

How do antioxidants work

Any discussion about antioxidants must inevitably begin with the free radicals. These are the unstable molecules that float around in our body looking to pair off their electrons with the electrons of other molecules. They are unstable because of their lack of a paired electron. As a free radical grabs the electron from a nearby molecule, this molecule in itself becomes a free radical because it is now unbalanced due to its missing electron. This in effect will set off a chain reaction for this newly formed free radical will grab the electron from yet another molecule. Science has indicated that these free radicals may actually damage cells and even the DNA and overtime may lead to premature aging, heart diseases and many forms of cancers.

Free radicals naturally form in our body through a process called oxidation, when oxygen interacts with matter like a cut apple turning brownish. But, we also get free radicals from external sources like air pollution such as cigarette smoke and the ultraviolet rays from the sun, and lifestyle choices such as unhealthy diets, excessive stress and even from exercising.

What antioxidants do is that they scavenge and quench these free radicals by supplying that needed electron and thus rendering them harmless. The ‘spent’ antioxidant might be regenerated by another antioxidant or remain in a harmless state.

Actually the human body produces its own antioxidants called antioxidant enzymes such as glutathione peroxidase and superoxide dismutase. But, as we age the body’s own defence mechanism may become less effective. Or, due to the demands of modern living, it may be just so much that the body can take. We will then need to supplement our antioxidants from fresh fruits and vegetables or plants such as green tea antioxidants.

The components of green tea antioxidants

I have categorized the main components of green tea antioxidants into 3 headings below. Together they form the powerhouse of green tea antioxidants. However, to better appreciate the wonder and power of these green tea antioxidants, these components must not be seen in isolation but rather in the light of their working together synergistically. To this end, it must be mentioned that we are merely scratching the surface for science has yet to fully understand the reportedly numerous phytochemical compounds in green tea.

Green tea polyphenols

A group of these polyphenols called flavonoids which can itself be sub-classified into types of catechins are the primary antioxidants in green tea. Of these green tea polyphenols catechins, special mention must be made of its main protagonist called epigallocatechin gallate (EGCG). This EGCG is often reported in many laboratory studies to be several times more powerful than Vitamins C and E in its antioxidant activity and at least twice that of resveratrol which is the primary antioxidant in red wine. Such is its repute that there seems to be a tendency toward over-emphasizing on the EGCG and the other catechins as evidenced by their composition in green tea extracts and their use in supplements and laboratory studies.

Green tea vitamins

The principal vitamins in green tea which have antioxidant properties are Vitamins C and E. Other vitamins present in green tea include Vitamins A, B2, and K. As antioxidants differ in structure such as whether they are water soluble or fat soluble, in certain environments within our bodies antioxidant vitamins may be even more suited or ‘specialized’ than the catechins themselves in scavenging free radicals. Moreover, researchers have indicated that Vitamin C might actually help in the absorbtion of the catechins into our bodies. These points will be discussed in more details in my related article on green tea vitamins.

Minerals

The minerals that are found in green tea include calcium, chromium, manganese, magnesium, selenium, sodium, phosphorus, potassium, strontium, iron, copper, zinc, cobalt and nickel. Although most are not known to be directly related to antioxidant activity in our bodies, I mention them here because some of them are essential in the formation of our bodies’ own antioxidant enzymes which we alluded to earlier. For example, the trace mineral selenium is as essential element in the formation of glutathione peroxidase. Similarly, manganese, copper and zinc are essential for the different types of superoxide dismutase.

A special mention must also be made of the amino acid theanine. Although not known as an antioxidant as such, the calming effect of theanine is often reported to be a natural stress reliever and excessive stress is a source of free radicals.

The generally recommended consumption of green tea is between 3 to 6 cups per day for its health benefits. It is definitely much safer than popping mega doses of antioxidant supplements and exposing to the potential toxicity thereof. It has also to be noted, however, that the content of green tea antioxidants vary greatly in the form of green tea products you consume, whether it is loose leaf, bag or bottled.