Beneficial Effects of Green Tea – Tea 1

Tea is one of the world’s most most popular beverages. Tea drinking very likely originated in China and there are various legends surrounding the origins of tea drinking. One legend claims that Shen Nong in 2700 BC set out to find out about the effects of eating various plants, so he tasted over 100 plants in a single day. Luckily he had a transparent stomach so he could directly observe their effects. Tea leaves apparently were able to clear out poisons. Ummm…. yeah. A slightly more believable legend claims that Shen Nong was boiling some water in a pot, when some leaves fell in. After tasting over 100 plants that day, he discovered that tea, while bitter, could make him think quicker and see clearer.

Tea drinking went ‘viral’ and would have broken the internet had the internet only existed in 2700 BC. It spread throughout the world a little more slowly by the various ancient trade routes. Because unprocessed tea is quite bitter, the origins of the word come from ‘tu’ meaning bitter (like bitter melon). In the mid 7th century, a stroke was removed and the word became ‘cha’.  Virtually all the words for tea in all the different languages of the world are variations are either ‘tea’ or ‘cha’. The ancient Chinese Min Nan dialect of the Fujian province used the word ‘te’ so spread via sea trade translated into the English ‘tea’ to as far away as the Maori ‘tii’. The dialects in landlocked regions of China used the word ‘cha’ and spread via the ancient Silk Road led to the Swahili ‘chai’ and as far as the Russian ‘chay’.

Interestingly, much of the early writings about tea touted its medicinal effects, particularly on digestion, rather than the (bitter, kind of metallic) taste. Tea is the leaf of the plant Camellia sinensis, and is consumed as green, black and oolong. Most of the purported health benefits have focused on green tea because of the high concentration of polyphenols and the beneficial effects of a chemical compound called catechins, the most abundant of which is epigallocatechin-3-gallate (EGCG). According to traditional Chinese beliefs, tea may be beneficial for weight control. This fascinates me, because our current research may only now be catching up with what those ancient Chinese people knew.

An estimated 2.5 million tons of tea leaves are produced annually, with some 20% becoming green tea. The oldest tree in existence is an estimated 3200 years old (pictured here) and lives in the Yunnan province of China where Pu-er tea is believed to have originated. China’s culture, along with tea drinking spread to Korea and Japan by 200AD.

In the 1500s, Portuguese traders brought tea to Europe and by the 1600s it spread to England, who spread their cultural tastes (and their famous stiff upper lip) to much of the rest of the world. The English bought so much tea from China that they developed a huge trade deficit as the Chinese didn’t really want any English stuff, other than their silver.

So, the English introduced opium for the express purpose of creating a nation of addicts, which would happily (for the English) balance their trade deficit. The Chinese government were not nearly as happy about their burgeoning opioid crisis and moved to ban the trade, but in true gangland, drug-pusher style, the English sent in their big gunships to make sure the opium flowed freely. Thus began the two Opium Wars that eventually won England the ports of Hong Kong, Shanghai and others. As if that were not enough, the English then proceeded to smuggle some trees out of China and set up plantations in India to break China’s 4000 year old monopoly. That’s the kind of ruthlessness that wins you a global empire and probably why the English are the bad guys in the movie ‘Pirates of the Caribbean’.

Different teas come from the same tree species but undergo difference processing. Freshly harvested leaves are immediately steamed, rolled and dried. This inactivates the enzymes responsible for breakdown of color so it becomes the stable green tea leaves you can buy anywhere. This also helps preserve the natural polyphenols in the leaves. If the leaves are fermented, they become Oolong tea, and further fermentation produces black tea. The polyphenols and catechins become changed to theaflavins, which may have their own beneficial effects.

Green tea contains much higher concentrations of catechins than black teas, accounting for up to 30% of the dry weight. However, standard brewing methods are insufficient to fully extract them so many studies use catechin enriched green tea extracts to get the high doses necessary. Cold brewed green tea is another potential solution to that problem (available here). These catechins are potent anti-oxidants, which may help the body protect against the ravages of inflammatory insults. Anti-oxidants are compounds that protect cells against reactive oxygen species, which may lead to cellular damage. In addition, there may be some protective effect against cancer, Alzheimers and Parkison’s disease, albeit mostly in animal studies.

Obesity

Two human studies suggested that catechins in green tea may help with weight loss. The first study gave healthy volunteers a beverage containing green tea catechins, caffeine and calcium 3 times per day and compared the 24 hour energy expenditure.

The green tea concoction increased the amount of calories burned by 106 cal/day or 4.6%. It is not possible to know whether the effect was due to the catechins, caffeine or calcium. Given that calcium has no known effect on metabolic rate, most believe the effect is due to a combination of catechins and caffeine. Luckily for us, green tea naturally contains both catechins and caffeine.  In comparison to other studies of caffeine and metabolic rate, however, this green tea drink performed 50-100% better than expected compared to caffeine alone. Heart rate and blood pressure did not differ between the groups, so there was no evidence of excessive sympathetic stimulation by the caffeine that could explain the increased energy expenditure.

This echoes the results of an earlier study (Dulloo AG 1999) that found almost identical results, even though this study used half the amount of caffeine, they also showed a similar 4% increase in metabolic rate.

In this study, caffeine given alone did not increase energy expenditure. Most studies support the combination of caffeine and catechins, which is found naturally in green tea, although the concentrations of both are much higher in the extracts compared to brewed tea. The 2011 meta-analysis, comparing all studies on green tea, came to similar conclusions that catechin-caffeine mixtures increased energy expenditure by 4.7% and further, found evidence of a dose-response relationship. Only the catechin-caffeine mixtures increased fat oxidation. It was noted during the Cochrane review that no study supported the use of brewed green tea, compared to the small but consistent benefits seen with green tea preparations that contain higher levels of catechins. A potential solution for naturally enriching green tea was discussed in our last post.

Catechins inhibit the enzyme COMT that degrades noradrenalin and cAMP. Blocking COMT increases noradrenalin, explaining the increased energy expenditure. Interestingly, there are genetic differences between COMT activity between races. Asians have higher rates of the high activity COMT(H) allele compared to some Caucasians, which have higher rates of the low-activity COMT(L) allele. Since Asians have the higher activity of COMT, blocking it with green tea catechins would be predicted to show greater effects, explaining the racial difference in the effect of the green tea catechins seen in some studies (1.51 kg versus 0.8 kg weight loss in Asians versus Caucasians).

Green tea promote long term weight loss by maintaining basal metabolic rate. Yes, the effect is not huge, but battles are always won on the margin. The difference of 100 calories per day multiplied over years can be very significant. This is reminiscent of the discussion of high blood pressure. We know from many clinical trials that if you lower the blood pressure by a little bit, it has huge benefits when multiplied over millions of people and over decades of time. The same applies to obesity and control of metabolic rate.

All of medicine comes down to risk versus reward – you can’t measure one alone to get a sense of whether or not a treatment is useful. That is, cutting off you arm is a very good treatment for a mosquito bite, but the risk is not worth the reward. So, yes, the rewards are relatively small, but perhaps important over the long term. But the risks are virtually non-existent. Even the most strident critic would be hard pressed to come up with a problem with green tea consumption. Thus the benefit/risk ratio is very heavily in favor of green tea.

So why wound’t you use it? I can’t think of a single reason.

 

2018-03-13T12:49:32+00:0042 Comments

About the Author:

Dr. Fung is a Toronto based kidney specialist, having graduated from the University of Toronto and finishing his medical specialty at the University of California, Los Angeles in 2001. He is the author of the bestsellers ‘The Obesity Code’ and ‘The Complete Guide to Fasting’. He has pioneered the use of therapeutic fasting for weight loss and type 2 diabetes reversal in his IDM clinic.

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BobM
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BobM

One reason: stomach upset. I have no idea whether what you’ll be selling will cause stomach upset, but I’ve been having trouble lately with tea and herbal teas. It’s gotten bad enough to stop me from using them during fasting. I’ll report back once I buy yours. Another reason: some people have a problem with plants. There’s a group of people who eat nothing but meat because they have trouble with plants. I initially thought they were crazy, but now I’m not sure. The fewer plants I eat, the better I feel. I am not eating just meat, yet, but… Read more »

Kristin
Guest
Kristin

It’s likely due to the tannic acid. This can be prevented by adding a small amount of fat to your cup of tea. I usually use cream but during a fast somemct oil or coconut oil should do the trick.

kathleenannjohnson
Member
kathleenannjohnson

If I drink several cups of green tea over several days, I never fail to trigger a migraine (and it’s worth mentioning: I rarely get them). So I have to be careful.

N1coleS
Guest
N1coleS

I also cannot have caffeine and green tea is the worst culprit. Coffee and tea rot my guts. I would give anything to be able to add it back into my diet. I don’t know anybody else who suffers from this caffeine sensitivity like I do. I would like to try Dr Fung’s tea to see if it will have the same gut impact as the many others I have tried. I have hope that the year of fasting and weight loss has led to healing and less of a response to this.

TeeDee
Guest
TeeDee

Hi, Nicole, have you established without a doubt that it is the caffeine causing problems for you? I can have caffeine in my morning coffee with no problems, but it is only tea that gives me the nausea..

Debby
Guest
Debby

Same here.

TeeDee
Guest
TeeDee

I’m so glad to see this comment. I’ve never come across anyone else who gets stomach upset from tea drinking (perhaps because I never told anyone else or looked around for info on it, yet.) I’m ok with chamomile and peppermint, but as soon as I have a cup of orange pekoe or green tea, I get very noticeable nausea. Thanks again for commenting on this, Bob.

K. Wood
Guest
K. Wood

I have to agree. Both tea (including green) and coffee induce significant nausea when fasting beyond 2 days.

Anon.
Guest
Anon.

One possible reason not to use it: tooth staining — though dental cleanings can remove the stains periodically.

JohnLocke
Guest
JohnLocke

Benefits VS Drawbacks (like anything in life).
If you care more about health than tooth aesthetics, the choice is easy.

gpisabela
Guest
gpisabela

And another reason: menopause with too much nor-adrenaline already (actually, too much of all sympathetic stimulants). This is why I gave up fasting, too, exactly when I started to see weight-loss benefits 🙁 palpitations, not enough sleep etc

Laura H.
Guest
Laura H.

What kind of fasting were you doing? Was it the 16/8 basic plan, or more than that? I just came through a period of heart palpitations and etc as you mention and do not want these symptoms to recur if I use this method.

gpisabela
Guest
gpisabela

16/8 doesn’t seem to affect me so much, I was doing 24h fasts 1-2/week when the insomnia started. I don’t know if it started solely because of the fasting, or fasting combined with pre-menopause. It’s been 1 1/2 years, taking bio-identical hormones, and still having palpitations and occasional insomnia, especially if I try to lose some weight. I feel like I’m walking on a tightrope with eating, too restrictive and storm starts, too lax and I gain weight like crazy.

TeeDee
Guest
TeeDee

Menopause/post-menopause is an ‘interesting’ time, that’s for sure. I could handle dairy my whole life, but now, except for aged cheeses like cheddar, I can no longer tolerate cream, sour cream, cream cheese, blue cheese, feta cheese, etc. I break out all over my face with red, inflamed pimples. I don’t know if it’s because I’m post menopausal or because I’ve greatly cleaned up my diet (I now follow a ketogenic diet and love it), but it’s bothersome to break out in zits at 61 yrs old 😉

Jim
Guest
Jim

We have long enjoyed Japanese style preparation of green tea. The stuff is great.

Karim
Guest
Karim

Its weird you quit taking about cancer and you talk now about tea !

TeeDee
Guest
TeeDee

In all fairness to Dr. Fung, when did he ever “quit talking about cancer?” He has posted some extremely important articles on it, recently..He posts on fasting, weight loss, kidney function, cancer and anything else he feels will cut through the propaganda that mainstream health proponents put out there. We’re simply letting him know how some of us feel about green tea, right now..

Stan
Guest
Stan

Like you guys or gals I have been struggling with some unneeded pounds, so I decided to change it. One time I heard a saying: nothing changes unless you make a change, then started searching information about dieting, nutrition, hormones, etc. and found something that was just right for me and working to melt fat. It is as simple drinking tea –recipe from Elizabeth Swann Miller (she wrote 7 books available on amazon). Feel free to try it yourself. http://bit.ly/2GsFAuA

JohnM
Guest
JohnM

Fair warning about the link above. It took three separate attempts to finally kill the web site that continues to reappear and restart. SPAM pure and simple. Am now running virus scan to see what else the ‘scat’ might’ve dragged in.

Sue and Tony
Guest
Sue and Tony

Looking forward to trying your tea. I’m not a tea drinker but when I fast I do find it helps!

MOA
Guest
MOA

I find camellia sinensis tea (white, green, oolong, black, I love them all) consumption increases water loss during the fast, which already has strong diuretic effects on its own. So watch out for electrolyte imbalances.

Laurel
Guest
Laurel

I’m an Earl Grey lover. I’ve tried drinking green tea several times but the flavor is awful to me. Bummer. I know I could take a pill containing EGCG but… meh… taking too many supplements already.

Benthamite
Guest

Over and over again I hear of miracle foods. A tiny amount of an antioxidant it is claimed promotes healing and protects effectively every cell in the body from reactive chemical produced in metabolism. The evidence supports the opposite, and green tea is no exception. Population studies without controlling for contravening variables don’t prove the point. For tea drinkers as a group the contravening variables are tobacco and ethanol, which they use less of. The contents of polyphenols and antioxidants are in too low an amount to be significant. A much better alternative is to take a mega dose of… Read more »

JohnM
Guest
JohnM

We are culturally driven to do the exact opposite of Douglas MacArthur’s statement: “Don’t just do something, stand there!”.

Fasting requires us to do nothing – to wait for our innate biological magic to correct what we screwed up. Taking any action at all makes us feel that we are contributing positively to fixing a problem. It immediately removes an irritating and most stressful item from our mental to-do list. That that action has already been proven ineffective doesn’t matter one bit.

The point? Never underestimate the power of self-deception.

Benthamite
Guest

Agree with your last comment. It is known as the ad post hoc propter hoc fallacy (also the ad post hoc fallicy), after this because of that–translation from Latin. Fasting is hard, but easier than a starvation diet. Watch this 13 minute documentary on “Fasting vs. Eating Less” https://www.youtube.com/watch?v=APZCfmgzoS0&spfreload=10. They don’t get better than this series in quality.

Anjo Draaisma, PhD
Guest
Anjo Draaisma, PhD

“Miracle foods” are useful if you lead a healthy life style. It will not work if you smoke and drink. There is also proof that, if you live a healthy life style and use varied foods, supplements intake isn’t necessary. I think there are a lot of risks taken 325 mg aspirin a day. Again, a healthy life style also lowers the risk of getting cancer. Eat well, sleep well, move well, and fast well, that is my motto against illness.

Benthamite
Guest

A reply to Anjo Drasiama: I would like it if you checkout what has been discovered about aspirin in the last 4 decades. I have it up on my website at http://healthfully.org/rc/id3.html. The salicylic acid form is widely distributed in plants as part of plant’s immune system, and mammals have evolved uses for it, including turning on a necrosis system which causes the body to destroy cancer. It promotes natural healing. Just check out my posting with links at http://healthfully.org/rc/id3.html. There are about a dozen healthful processes promoted. Remember that pharma is in the business of treating illnesses, and I… Read more »

Gail Lackey
Guest
Gail Lackey

Why is it in USD and shipping free from US? Dr Fung In Toronto Canada.

steve B
Guest
steve B

does the fermenting of the oolong or black tea make it healthy? or healthier than green tea?

P Kelly
Guest
P Kelly

I am concerned about the high levels of lead that have been found in tea from China, due to their manufacturing without environmental controls we have here and in Europe. Where is the tea sourced?

C T
Guest

I have a reason to be very cautious with high green tea consumption. You mention that it inhibits COMT. Well, in combination with high levels of proline, that apparently can cause/exacerbate negative symptoms of schizophrenia. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5048199/ You’ll notice that schizophrenia rates tend to be quite high in places where they have high intake of both green tea and proline. Everything has downsides.

Alan K. Bricker
Guest
Alan K. Bricker

Dr. Fung’s comments would be welcome on the subject of “Matcha” green tea.

Ronald C.
Guest
Ronald C.

Risk vs Reward
I have Liver function tests done regularly . ASL and ALT. My experience after taking Green Tea Extract ( not the Tea) was a raise in these Liver function tests.

Linda
Guest
Linda

I have bought both of your wonderful books and follow your blog but worry that you have begun to “sell” your products so vigorously that I am beginning to question your devotion to the topic of good health.

Teafree
Guest
Teafree

Another reason: acid reflux.
And another: the addictive quality of caffeine.

Roger Bird
Guest
Roger Bird

Another very interesting article. But I have to correct the good doctor (such are so rare). The oldest tree and the oldest trees in the world are: Until 2013, the oldest individual tree in the world was Methuselah, a 4,845-year-old Great Basin bristlecone pine (Pinus longaeva) in the White Mountains of California. Researchers at the Rocky Mountain Tree-Ring Research Group then announced the age of another P. longaeva also located in the White Mountains — this one 5,062 years old. (https://www.livescience.com/29152-oldest-tree-in-world.html I’ve been there.

vijay
Guest
vijay

I found a research paper comparing black, oolong, green and white tea–cold and hot brewed. Please read the whole paper. “White tea cold brewed” seems most beneficial. I have the full pdf document. https://www.sciencedirect.com/science/article/pii/S0308814609011091

David
Guest
David

Any thoughts on pu erh tea?

Noor Ullah jan Jan
Guest

Thanks for the well-detailed info.
Green tea is among the best options for weight loss and the reason is the presence of potent Catechin, low caloric values, and its aroma.

Sylvia
Guest

I disagree. Teas – especially most popular: black, green and red contain a lot of fluoride. Drinking 2 cups a day is OK but more will cause fluoride overdose. Moderation is the key – as always.

Anjali
Guest

A lot of benefits of green tea. You have explained the topic in a fabulous way. I am glad i visited your website. Green tea is like a mine of health benefits. Thanks for sharing the fabulous content.

Joshua
Guest
Joshua

Green tea is loaded with plenty of health benefits. It possesses several nutrients and some active molecules that shows excellent pharmacological significance. I have gone through an article entitled “ 10 Benefits of Green Tea That Everyone Should Know” at zovon.