Sunday, June 17, 2007

Green Tea


Over the last couple of days I have been doing a little research on the health-giving aspects of tea. I have to admit to being a bit of a cynic when it comes to alternative medicine but I am now convinced that there is something of great benefit in tea.

Green tea in particular seems to have some therapeutic qualities. Recent studies have linked it to the prevention of cancers (particularly squamous cell cancer of the skin and esophagus, the prostrate, the breast and the ovaries), cardiovascular disease, strokes, arthritis and Alzheimer's. In fact it appears to be some sort of wonderdrug.

The active ingredient in green tea is something called epigallocatechin gallase (EGCG) which is a sort of flavonoid. This is just the name of a set of chemicals that are derived from plants. In the freshly plucked leaf there is 10% EGCG by weight but this is destroyed when the leaf is 'fermented' and turned into the black tea we normally drink.

EGCG is a powerful antioxidant and this, until recently, was thought to be the reason for its anticancer action. The flavonoid was thought to work by 'mopping up' the harmful free-radicals that can damage cells and lead to cancer. However in March Professor Frei at the Linus Pauling Institute found that this was not what actually happened in vivo. Flavonoids only work, he says, because they are slightly toxic and the body can't wait to get rid of them. Only about 5 % is absorbed and in response to even this small invasion the body produces substances like uric acid to expel the toxin as soon as possible. And it is this expulsion that causes the anticancer effect. The mechanisms that expel the flavonoid also eliminates mutagens and carcinogens. The body is put in a state of alert and is sensitised to any invader. The system is purged. There is a detoxification on a grand scale.

So green tea is good, but you don't need too much. In fact too great a dose of flavonoids can be harmful so it is best to keep the doses small and often. A healthy diet of 5 - 9 portions of fruit and vegetables a day should do the trick, according to Professor Frei, there is no need to go mad.

And at least a couple of these portions can include green tea (which must be carefully stored and steeped at 100 degrees to extract as much EGCG as possible according to another study), and with a little persistence I am sure it is possible to get used to the taste - which is, unfortunately, quite disgusting. At least in my opinion.

6 Comments:

Blogger Susangalique said...

I like to add a small bit of honey to my tea when I drink hot tea. Most of my fellow southerners like cold sweet tea with heaps of sugar but I like my cold tea un sweet.

do you think honey would interfere with the green tea, but sometimes when your cold and sick some bla tasting tea is good in an odd sort of way.

Sun Jun 17, 10:49:00 pm  
Anonymous marly said...

Hah, hah!

I like the penultimate line--not what I was expecting, Clare...

Perhaps you should cheat and mix green and black together. I suppose that is allowed, though no doubt regarded as barbaric.

And what about "white" tea?

Mon Jun 18, 12:13:00 am  
Blogger Lee said...

I happen to love the taste of unsweetened green tea, even cold (very refreshing in summer) but you can also try combining it with fruit/herbal teas - rosehips give a very pleasant mix, for example. No idea how this affects the flavonoids, however.

Mon Jun 18, 05:50:00 am  
Blogger Jason Erik Lundberg said...

Isn't it also supposed to make you smarter? I seem to recall a study on lab mice that showed increased brain activity, but I'm too lazy at the moment to go and find it. Maybe I need some green tea.

I've gotten used to the taste, since living with an Asian wife means I drink it fairly often (especially now that we're in Singapore). I also didn't like the bitter taste at first, but it has grown on me.

Mon Jun 18, 07:01:00 am  
Anonymous clare said...

Susangalique: I like the sound of honey. I don't think sugar interferes but there was a report that milk did. It tied up all the flavonoids and stopped them entering the blood. But then another report found the opposite.

Marly: Yes, I have invested in white tea too. It is virtually tasteless and a bit like drinking boiled water. Apparently it is better than green tea though and has a much higher concentration - though how this can be in 'white' tea that must have been stored for weeks, i don't know.

Thanks for the tip, Lee. Now did I read today that rosehip is a cheap alternative arthritis medicine? If so, sounds quite a winning concoction.

Jason: Now I'd not read that. I wouldn't be at all surprised though given that it apparently helps stop plaque formation in Altzheimers and also increases the concentration of a desirable brain chemical - dopamine, I think. And yes, I am sure it is something you can get used to. My trouble is I keep it next to the coffee and that is always the one I end up choosing.

Tue Jun 19, 04:05:00 am  
Blogger Minx said...

Whittards Of Chelsea do an instant green tea which is also flavoured (white cranberry and hibicus?) and very palatable. Their range of instant teas are yummy (Cranberry/ Raspberry and Dreamtime especially)hot or iced.

Wed Jun 20, 11:50:00 am  

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