Tuesday, May 7, 2019

Green tea: a dietary risk I didn't know about

I was surprised to learn that green tea in high concentrations can be a health risk.

A 16-year-old girl developed acute hepatitis about three months after adding Chinese green tea to her daily diet, states a report in BMJ Case Reports. At first, the girl told the doctors that she wasn’t taking any over-the-counter medicine that could have caused the problem.

However, despite signs of liver damage, the doctors couldn’t find any other sources, such as a viral, autoimmune or metabolic problem. That’s when more specific questioning revealed the girl had ordered Chinese green tea online.

According to Live Science, the girl didn’t know all of the product’s ingredients due to Chinese labeling. To further confirm the doctors’ suspicions, the girl quickly recovered from her hepatitis once she stopped consuming the green tea.

There's more at the link.

It seems that the highly concentrated supplements she was drinking, added to a highly concentrated form of green tea, caused the problem.  Green tea in concentrated form can cause a reaction in the liver.  In this case, that led to hepatitis - fortunately not the permanent variety!

I drink green tea now and again, although I prefer black;  and I tend to make it pretty strong, because that's how I like all my tea, regardless of what type it is.  I'll have to re-think that.  Those of my readers who do likewise might wish to do the same.



D.J. Schreffler said...

How about sweet tea? Especially the iced variety?

That's a must for the Texas heat.

Cedar said...

Or just don't drink green tea from China. You don't know what's in that besides tea. Quality control is a thing!

Peter B said...

The paper was kind of interesting.

Despite the fact that the authors refer to the toxic product as “green tea,” it almost certainly wasn’t only green tea. It "contained Camellia sinensis*.. The patient herself stated "most of the ingredients of the tea I bought were written in Chinese."

So the most we actually know is that green tea was reportedly among the ingredients of the product. The authors of the paper do not elaborate on this, so we should assume they don't know the other actual or purported ingredients either. (I think the BMJ is slipping. I've published a case report in a respected journal and my editor wouldn't have let me get away with not stating this explicitly and probably would have insisted that I make an effort to find out what all the ingredients were.)

The authors are aware that they are not actually sure it whether the other ingredients, the green tea itself, or contaminants – not a big stretch for Chinese (or Indian, or…) products – that was the problem:

It is the secondary or tertiary processed products, rather than the freshly made leaves [sic], that have been described in previous case reports.
This raises the possibility that it is the addition of other chemicals causing hepatotoxicity, particularly in preparations used for weight loss. Also, pesticides may be widely used during the growing of tea trees and are known to contaminate green tea infusions. There is potential for pesticide-induced hepatitis to exist, especially from less regulated products ordered from developing countries over the internet.

I'm assuming they mean "freshly made tea." The secondary or tertiary products they refer to are probably alcohol and water ("hydroethanolic") extracts of tea leaves and highly concentrated EGCG (epigallocatechin gallate, which is one of the medicinally active ingredients in green tea.)There are indeed numerous reports that these have indeed caused liver problems. Brewed green tea, not so much. Until this report. Maybe. Given what we know so far, I'm more prone to lay the blame on contaminants or those unknown ingredients.

For myself, I'm not going to stop drinking tea, though I am pretty careful about the sources from which I buy this particular drug.

GMP certification, if not corrupt or a forgery, is probably a reliable way to verify that the ingredients of a product are as stated. Organic certification, as problematic as that can be, is probably the best place to start as far as pesticide and herbicide contamination goes.

People who do take EGCG for medical reasons (and there are some valid ones) should probably monitor their liver function regularly.


*C. sinensis var. sinensis is the plant whose green leaves are processed to make green (and black) Chinese teas; other green and black teas are made from the Assamese variety of C. sinensis.

Jonathan H said...

There have been several reports and studies recently showing that quality control is either abysmal or totally lacking on "Traditional Chinese medicine" (often called TCM) and that many products not only don't contain the advertised major ingredients, they DO contain toxins and allergens that are not advertised.
Unfortunately, this is yet another example of 'buyer beware' applying to Chinese merchandise and another reason to avoid it for anything important.

Beans said...

Yeah, what others have said. I'll go right out and buy that traditional Chinese medicine green tea that probably gets its color from antifreeze or some other industrial waste being used as a 'preservative.'

First rule. Don't order your meds of any variety, real or 'traditional,' from a source that doesn't speak the same language you speak, as good or better than you speak.

Our 'supplements' are bad enough, but at least most sold in stores have some quality control behind them. Though even then, one must be careful to avoid the toxicity levels of various things (yes, I have seen someone make themselves orange, really orange from eating too many carrots...)

Some people's kids, yeesh.

LL said...

Black tea contains elements that are not healthful, too. The question is more one of quantity, though. If you cut it out and you go into withdrawals - same with cola, coffee and other caffeinated beverages - (headache, etc.), maybe it's time to cut down how much you drink.

I've grown spearmint and chamomile, both of which are brewed into tea. Dried spearmint, for example, can be purchased from reliable US sources that don't add anything. I'm with Beans when it comes to food and beverage that originates in China. Best to avoid it.

Larry said...

A coworker's family is in the tea business in China (i.e., plantation). He says never, ever buy the chopped processed stuff from China. Only whole leaf tea is reasonably safe except for pesticides. He only drinks what comes from his own family.

Peter B said...

Larry is right. The Chinese born Tai Chi teacher who taught us how to brew tea gongfu style (explaining why for each step of the process) mostly drank high grade oolong teas.

The first thing you did with the tea was to pour water of the correct temperature over the leaves, let it sit for a about 30 seconds, and then pour it all off. This was to help the rolled leaves start to open up – and to rinse off dust and "impurities." He did this even with the good stuff. You didn't drink this liquid, though you used it to warm up the cups before the first pour of tea.

He had managed to stay away from the Japanese and the Communists and make it to Taiwan after the war. One of his school friends came from a family that had a tea plantation in the mountains and kept him supplied in later years. The family grew tea for the market but grew the really good stuff for themselves, for entering into competition, for "gifts" to officials and for friends.

He brewed one of these teas for us one time. I think it had been the second prize winner in a big competition. This was in the early 1980s and he told us "If you could buy this it would cost over $400/lb." It was absolutely amazing. You wouldn't think you could remember a cup of tea for over thirty years, but you can. He rinsed those leaves too.

There is an indescribable mouth feel to good, well brewed oolongs which is apparently an organoleptic test correlating with increasing amounts of beneficial polyphenols in the tea. Basically you get more of those per milligram of caffeine and related compounds the better the tea is.

In black tea, the polyphenols get oxidized and the tannin content increases, though the tannins have some beneficial properties too.

Francis Turner said...

Definitely go with the rest regarding the sourcing recommendation. I'd trust Japanese origin green tea a lot more than I'd trust Chinese (PRC) origin green tea. I would probably trust Taiwanese origin teas though it can be hard to tell which china is which

Also (FWIW) as an Englishman I, of course, want my black tea brewed from water that is boiling or as close to boiling as possible. You do not want to do that with green tea. For green tea you want the water to be in the 150-180degreeF range and to do what PeterB says and discard the first brewing.

m4 said...

Alas I can't read the article (Access Denied), but I would like to point out that we had a case here not long ago with green-tea-related liver failure. However in that case it was green tea supplements, rather than actual tea. I vaguely recall from that article that the health risks of tea in tea form were not to be concerned about.

Chuck Pergiel said...

The British Empire was built on Black Tea. Only heathens and unrequited sycophants drink green tea. Whatever a sycophant is.

Antibubba said...

It seems a steep price to pay.