Saturday, January 14, 2012

Does Green Tea Protect Against Fatty Liver Disease?

by Chris Masterjohn

Nutrition Reviews just published a review that I wrote with my doctoral advisor on the potential of green tea to prevent or reverse nonalcoholic fatty liver disease.  Nutrition Reviews is a widely cited journal, ranking ninth out of 70 nutrition and dietetics journals.  The review is indexed for pubmed here, and if you'd like to read it you're in luck: the journal has decided to make the entire January issue available for free, so you can download the full text here:


Please note that this is a collaborative effort, and anything I write myself on this blog or elsewhere about fatty liver disease does not necessarily reflect the views of anyone I have collaborated with in this or other papers, my university, or the journals we have published in.

Read more about the author, Chris Masterjohn, PhD, here.

43 comments:

  1. Well done Chris. It looks like a very in depth review and in a really good journal.

    However you may wish to check the spelling of the title of your post :)

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  2. Very nice, the topic of GTE has piqued my interest recently. I am a little curious about the diets used to induce NAFLD though.

    A high fat >60% diet was used in one example, how was this formulated to induce NAFLD? (I've always heard a low-carb/high-fat diet improves fatty liver, but, I'm guessing there are other factors involved here).

    What about dosage? Sounds like ~700-800mg/day in humans is tolerated, as per the note near the end. Tim Ferriss in his "4-Hour-Body" book recommends three doses of ~300-400mg pills per day as part of his "PAGG" stack (weight-loss oriented) but I can never be sure the science behind some of the stuff in that book...

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  3. Hi Eric,

    I've never seen any quality evidence that a high-fat, low-carb diet resolves fatty liver. Could you point me to any evidence you've seen of this?

    In any case, the purpose of these diets isn't to blame "fat," but these diets are the most reliable way of causing obesity in rodents, and fat rats have fat livers, to paraphrase Jurgen Ludwig and co-authors from their landmark paper in which they coined the term "NASH."

    I'm a little uncomfortable recommending particular dosages of green tea considering the lack of evidence in humans for this purpose. I'm more inclined to say try drinking some green tea to taste! But one could experiment.

    Chris

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  4. Hasn't green tea been shown to lower testosterone levels?

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  5. Chris-

    After going and digging, I came to realize most of what I'd read about low-carb diets resolving NAFLD was rumor from low-carb forums and articles (Dr. Eades mentioned it in a relatively recent one about "starting or re-starting low carb diets" but all I saw was a "Studies show" reference with no link). Not very good evidence either way ;)

    However I did come across this-
    http://www.utsouthwestern.edu/newsroom/news-releases/year-2009/low-carbohydrate-diet-burns-more-excess-liver-fat-than-low-calorie-diet-study-finds.html

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  6. Your paper came up last week in my daily PubMed search alert, as I have tea as a search term. I was wondering if you were going to mention it. You might mention the side effects of green tea, such as calmness with alertness, reduced susceptibility to sunburn, as well as the less easily quantified benefits regarding cancer, dementia, etc. "White tea" also works. Unless you have poor access to bathroom facilities, the downsides of tea seem quite minimal.

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  7. Hi Rant,

    Do you have a reference for that?

    Hi Eric,

    Looks like that's the study I blogged about in April:

    https://blog.cholesterol-and-health.com/2011/04/new-fatty-liver-study-shows-that.html

    Hi David,

    Thanks for your comments. Those are way outside the scope of our review paper. Perhaps if I have a chance to make general comments about tea in the future as a blog post I will look into those effects. You make a good case for drinking tea. :)

    Chris

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  8. Congratulations on the new publication!

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  9. I suppose that the idea behind low-carb being good against NAFLD is more of a deduction than a study backed proposition. Where does the fat accumulated in the liver come from? From DNL most probably. On low-carb DNL is minimized, so no new accumulation of fat in the liver and the other factors involved in NAFLD (polyunsaturates and choline) are also changed in the right direction to help clear the liver from the accumulated fat. Of course, such a deduction should be backed by empirical or clinical evidence, but it is a rather obvious idea. If it is right or wrong is, of course, a whole other story.

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  10. Thanks Chris!

    Gallier2,

    That is not obvious at all to me. For one thing, most of the fat does not come from DNL. Most of it comes from circulating free fatty acids. DNL is dramatically increased but it still accounts for a minority of the liver fat. But there is nothing that screams "carbohydrate" about increased DNL anyway. Naturally DNL occurs from carbohydrate, but it is selective hepatic insulin resistance that leads to its increase, just as it is insulin resistance in adipose tissue that leads to the decrease in TG uptake and increase release of free fatty acids, and it is not clear to me that carbohydrate per se is to blame for any of these things. I agree with you that people who make this proposition should seek evidence for it, but I think they should also acknowledge the nuances of the issue that I noted here.

    Chris

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  11. Oh, I don't dispute what you said, I only wanted to say how that idea might have come about, nothing more.

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  12. Galler2, gotcha. Thanks for clarifying! That makes sense.

    Chris

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  13. Spectacular stuff. Matthew up there shared it with me, it's top-quality work. I have been interested in fatty liver disease for quite a while, I will have to reference this, not only in support of green tea but as a general didactic tool for learning fatty liver disease and what can be done about it.

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  14. @Eric B and Chris,


    Dietary composition and nonalcoholic fatty liver disease.,
    Solga S, et al.


    Quote: There were no significant associations between either total caloric intake or protein intake and either steatosis, fibrosis, or inflammation. However, higher CHO intake was associated with significantly higher odds of inflammation, while higher fat intake was associated with significantly lower odds of inflammation. In conclusion, present dietary recommendations may worsen NAFLD histopathology.

    And this article

    Quote: Compared with patients with the lowest carbohydrate intake, a high- carbohydrate diet was associated with an odds ratio of 7.0 (p = 0.02) for liver inflammation. A high fat diet appeared to be protective, with those in the highest fat intake group having an OR of 0.17 (p = 0.009). Dr. Clark noted that the study appears to support diets such as the Atkins Diet, but she declined to make a recommendation.

    (I posted about it here )

    Stan (Heretic)

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  15. Now we need to know how much there is EGCG in green tea and friends:


    Distribution of Catechins, Theaflavins, Caffeine, and Theobromine in 77 Teas Consumed in the United State
    http://ddr.nal.usda.gov/dspace/bitstream/10113/1807/1/IND43773084.pdf

    Also, keep in mind that you probably shouldn't binge on green tea (like... several litters per day) as it contains substantial amount of fluoride in such dose. White tea is probably safer

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    Replies
    1. hi, AHK is waiting for U to come back. Chris has left and i think you are the best to become one of the leader!

      Delete
  16. Most likely results are due to the caffeine. Confirming what we already know. I would question whether polyphenols are really antioxidant, probably the opposite and the caffeine is protective.

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  17. Chris, here's one study on green tea extract and testosterone inhibition - http://www.ncbi.nlm.nih.gov/pubmed/19330017

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  18. Congrats on the paper, Chris. Interesting comments on the blog here, also, specifically in regards to testosterone.

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  19. Chris,

    I'm curious as to what your macros are... not that it's terriby important but you and I share alot of characteristics (hemochromotosis gene, european ancestry, vegaterian past, smaller stature ;-) ) and I'm interested to see if our "optimal" diets are the same. I have heard you say you seem to need a certain amount of fat in your diet, but also lower in meat and that 150grams of carbs keeps you at perfect satiety. This is very similiar to what seems optimal for me but I go back and forth with higher carbs, lower fat and lower carbs and higher fat. Both seem to have their pros and cons for me and I am wondering some like folk have found the middle ground!

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  20. Responses to Stabby, Stan, Majkinetor, Anonymous, Rant, Mike, and Anonymous.

    Hi Stabby, Thanks I'm glad you enjoyed it!

    Stan, I'll try to look at these soon, thank you for passing them along. As we all know, correlations do not demonstration causation, but more to the point, even a controlled trial substituting foods with different carbohydrate contents would be confounded by choline intake, unless supplements were used to standardize choline intakes, so I am quite skeptical that these types of associations could indict carbohydrate per se in the context of the broader evidence. But I've been meaning to write a post on this for months now, so perhaps I will finally get to that and include these articles.

    Majkinetor, I agree that green tea consumption should not be excessive. I suspect the best way to protect against fluoride would be to consume it with a meal, especially a meal rich in calcium, since this would prevent absorption of the fluoride.

    Anonymous, as we note in the review, although most studies using green tea extract are confounded by including both catechins and caffeine, decaffeinated green tea stimulates beta-oxidation and EGCG alone protects against fatty liver. So the effects are not all due to the caffeine. Moreover, it is well established that green tea has in vivo antioxidant activity. The question is whether this is mediated through direct scavenging or through a hermetic effect, such as that mediated by the Nrf2 pathway, and the evidence is insufficient to say definitively, though I favor the latter hypothesis.

    Rant, that is just a cell study so I think it needs to be used to generate a hypothesis or explain something already be shown to be true in a live animal, but there are some other in vivo studies showing negative effects, but others positive effects, such as this one: http://www.ncbi.nlm.nih.gov/pubmed/20505988 I suspect the differences could be related to the model used, the dose, and then finally whether the animals are growing. Unfortunately I don't have time to review the literature comprehensively at the moment, but it's an interesting topic.

    Mike, thanks!

    Anonymous, my macronutrient ratios are all over the place, varying both over time and from meal to meal. I agree both have their pros and cons, perhaps the middle ground does too. :)

    Chris

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  21. References for caffeine free green tea benefits? And specifically caffeine free ECGC? ( Btw I am a regular matcha green tea drinker!)

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  22. Hi Anonymous,

    You can find the references in the review. Since it's in pdf format, they should be easy to find with a keyword search. (If you don't see the search bar in the corner, use control + f, which should make it show up).

    Chris

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  23. Thanks for the interesting research! I'm wondering whether the same health-promoting effects would be observed by consuming any type of green tea? Are there any differences with consuming loose tea leaves, powdered green tea and decaffeinated green tea bags? Hopefully, this research will progress to real human studies one day. Thanks!

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  24. Hi Water,

    Yes, presumably each tea will vary in the magnitude and perhaps type of its effect depending on its composition. You're welcome, and thanks for writing.

    Chris

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  25. I understand that Coffee is also hepatoprotective. Does it have a similar mechanism of action as Green Tea?

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    Replies
    1. Hi Jeff,

      Good question. Unfortunately I haven't researched the hepatoprotective effects of coffee, so I'm not sure how much similarity they bear to those of green tea.

      Chris

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  26. I hate to detract from your work, but if green tea and other polythenol/caffeine containing foods are protective against fatty liver condition, are we going to assume that:

    1./ A diet that is low in these protective compounds will inevitably lead to fatty-liver condition?
    2./ The condition is caused by other components oversupplied or under-supplied in the diet?
    3./ The condition has nothing to do with diet, but green tea can improve the chances of not getting it.

    I had always suspected the second situation, and you no doubt will say all three may be true because we don't have enough evidence - as we never have enough evidence for anything!

    Yet, you will admit that your leaning is towards no. 2 isn't it! admit it!

    So does green-tea have any practical value in preventing fatty-liver condition? after-all, if you can steer people away from a diet that puts a person at risk of fatty-liver condition, then the protectiveness of green tea would become quickly irrelevant.

    I would be interested to know what you think that diet may be - I am presuming it would be low in linoleic acid?

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    Replies
    1. Hi Gordon,

      Actually I think #2 is almost certainly true. Believing #1 would mean that almost everyone historically has had fatty liver and #3 is incredibly unlikely given the ease with which it is caused by dietary modifications in animal models, and its association with comorbidities in humans like obesity that have clear relationships to diet and lifestyle.

      You can find my basic theory on fatty liver in my Wise Traditions article, "Nonalcoholic Fatty Liver Disease: A Silent Epidemic of Nutritional Imbalance."

      http://www.westonaprice.org/health-issues/nonalcoholic-fatty-liver-disease

      The dietary implications are outlined there. Let me know if you have any further questions.

      Chris

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    2. ...

      I will also raise again the experiment of Jed Friedman's monkeys, have you had any more chance to read his work? - I can't help thinking his experiment has proven that obesity can be triggered by neo-natal environment via fatty-liver disease - and further that O6/O3 ratios are a marker if not causal.

      I am a strong advocate of the weight-set-point understanding of obesity, in that dietary aspects have little effect on obesity in adulthood (long-term). I don't suppose there are any clinical results to show that reversing fatty-liver disease in adults can result in long-term reversal of obesity, which would challenge my understanding? I certainly would not have thought that "obesity has a clear relationships to diet and lifestyle", at least not in the obvious manner usually assumed.

      I wasn't aware of the choline aspect, do you think choline deficiency is common in Western diets?

      Delete
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  30. It might be a worthy experiment to do a batch with milk, just to see what happens. The tannins bind to the proteins in milk. Tannins will tan your liver and kidneys. Chances are you are right, it is the tannin. But there is a lot going on in tea. It might be prudent to test it further. If the mice still have fatty liver disease after drinking tea with milk, your thesis is strengthened.

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