Health Benefits of Green Tea

Is Green Tea is one of the most healthy beverages you can drink?   It seems it might just be!

Traditionally for thousands of years the health benefits of drinking Green Tea have been noted.  Historical references mention it’s ability to ‘refresh, increase alertness and ‘stave off disease’.

These days we can now back up these observations with research and we  have the science to analyse the tea leaves to find exactly what is in them that makes Green Tea so healthy.

Studies of the health benefits of green tea have now been published in many scientific journals world wide with the one conclusion….

The studies have pretty much shown that if you do so you will gain the following benefits…

• Lowered risk of cancer
• Slow the aging process
• Reduce you incidence of cardiovascular disease
• Help maintain healthy blood sugar levels, and even lower them if they are high.
• Fight viral infections and enhance your immune system.
• Prevent tooth decay, bad breath and gum disease.
• Help you maintain a healthy weight.

Now these are pretty monumental claims and I would encourage you to be pretty wary when you see lists of claims like this. 

But I can generally put my hand on my heart and say there is a lot of evidence to back up these claims these days – and you will see more and more of it to come as scientists are busily conducting studies all the time on green tea or green tea extracts.

• Some are well designed double blind placebo trials using either humans or rats.
• Some are what are called epidemiological trials where tea drinking data is collected over many years and observations are made from this information.
• Some trials use Green tea and some trials use green tea extracts, which are more concentrated.
• Some trials are small, some are very large.
• A lot, understandlably, have come out of Asia, but many more are being done in European countries now.

(I am not that fond of the Rat trials personally – when there are so many humans happy to drink tea for research.  So I tend to not refer to them if I can avoid it.)

Let’s start with a summary of what Green Tea is and then what is in it that makes it so health giving……

What is Green Tea?

Green Tea comes from the plant Camellia Sinensis which is a relative of the Camellia plants we commonly see in NZ gardens.  

The thing that makes a tea either green or black depends on how the leaf was processed.  The biggest factor here is the length of time the leaves are oxidised after they have been picked.

• Black tea is ‘Fully oxidised’
• Green Tea is ‘Un-oxidised’

Black tea is exposed to several hours of warm air – the longer the exposure to the air the darker the leaf becomes.

Green tea DOES NOT undergo this procedure which is why it keeps it’s green colour.

So how does this give Green Tea it’s superior health benefits?

It all comes down to the level of antioxidants left in the leaf when it has been processed…

The antioxidants found in the tea plant are classified as polyphenols and the four primary polyphenols are called catechins: epigallocatechin gallate (EGCG), epigallocatechin, epicatechin gallate and epicatechin.

Like other antioxidants, polyphenols prevent against the oxidation, and consequential degeneration and mutation of cells.

EGCG - is the dominant antioxidant – representing more than 50%.   

Green tea contains between 30 and 40 per cent of water-extractable polyphenols, while black tea (green tea that has been oxidized by fermentation) contains between 3 and 10 per cent.

An average 250ml cup of Green Tea will contain about 150-200mls of these polyphenols.

So basically Green Tea has a higher amount of the health giving antioxidants than black tea.

This is not to say that Black Tea doesn’t have antioxidants, it does, and it has some that are slightly different to green tea that have been created because of the oxidation they go through.

Go to here for more indepth information on Antioxidants.....

Green Tea is more than just Antioxidants

There are many more, often forgotten about, health benefits in green tea.   The Green Tea leaf is actually full of great vitamins and minerals that are also released into the tea when you infuse the leaves.

Green Tea contains the following nutrients…..

• Beta carotene – This is what we find in carrots.  Good for your eyesight, improves your immunity and helps keep your skin and internal tissues healthy.
• Fluoride – for healthy strong bones and teeth (Note: there is controversy about fluoride in tea that I address in the next paragraph.
• Selenium – for cell protection
• Calcium – for strong bones and to keep the body in an alkaline state.
• Potassium – for keeping you alert
• Vitamin C – Immune function, collagen health
• Vitamins B1 and B2 – Energy Production
• Zinc - wound healing, immune function, hormone balancing.
• Folic Acid – prevention of neural tube defects, cardiovascular disease prevention

The levels of these nutrients are dependant on what soil they were grown in and the growing conditions.  Each cup of green tea would give you trace amounts of these nutrients – the more cups you have, the higher the levels of nutrients. 

A couple of things to note.....

• Green Tea is well known in Japan as a great source of Folic Acid and contributes to their daily intake significantly.  A typical cup contains around 11.5mcg of folic aid.
• Vitamin C is only found in Green Tea as the oxidising of black tea destroys the vitamin C content.

Other than this there is not a huge amount of research into the levels of nutrients found in a cup – the exception here being Matcha Green Tea – which is the powdered form.  Since you ingest the tea leaves (as opposed to normal drinking of green tea where you infuse then throw away the leaves) with this form of green tea you get significantly higher amounts of all the nutrients, antioxidants and some extras like Fibre.

Tea and Fluoride

Before we move onto some of the studies on green tea I want to talk about this.  There is significant debate about the safety of fluoride in high doses, relating mainly to fluoridation of our water supplies.

I am not going to go into this debate, but I do want to say where Green tea sits.

Firstly it needs to be clarified that there are two main types of fluoride, and this is often not made clear when having discussing on potential safety of fluoride.

• Calcium fluoride - this is the natural form of fluoride.  This is form that is found in our bones and it basically where a fluoride molecule is bound tightly to a calcium molecule. It is not water soluble – that is it will not dissolve in water and the fluoride can not to separated from the calcium.
• Sodium fluoride – is the form that is added to our water.  It is water soluble so it dissolves in water.  It is easily broken from the sodium molecule to become free fluoride.  It is a synthetic form of fluoride.

The potential problem with fluoride is from the Free fluoride which is found after it has dissolved in water and broken it’s bond with sodium.

Tea contains the natural form of fluoride – calcium fluoride.  With the exception of some instant teas that often have added synthetic sodium fluoride in them.

So to summarise this Green tea is unlikely to cause you any problems with fluoride even if you drink lots of it.