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Kava Fact of the Day Kava and Green Tea in regards to liver injuries.


The Kaptain (40g)
KavaForums Founder
Hi kava lovers. Today we’re going to address a little bit of irony when it comes to liver health, warnings, and the beverages we consume on a regular basis. It may not be well known that some of the beverages and supplements we intake regularly, outside of alcohol, come with their own set of hepatic (liver) risks. We’re going to look at one for today, and that is the chemical EGCG which occurs naturally in green tea and occurs in great abundance in green tea extracts (GTE). I would like for this essay to serve not as a warning for green tea, but to compare and contrast the liver issue in regards to what we’ve seen with kava. Injuries involving green tea or green tea extracts are exceedingly rare, and are not a cause for widespread concern. Below I review the research involved in idiosyncratic herb injuries, and I would like to draw the correlation between this and the reports regarding kava and liver injury.

Let’s review the different types of herb induced liver injury (HILI), and their characteristics. We’ll start with idiosyncrasies. Idiosyncratic injury is a rare disorder that is not related directly to dosage, and little is known about the individuals who are at an increased risk. It’s unpredictable, there are no research models for the study of idiosyncratic HILI, its development is poorly understood, and it cannot be prevented [1]. Intrinsic toxicity and injury follows a classic dose-dependent curve and is predictable above specific thresholds. Essentially the intrinsic toxicity of an herb or drug is the identification of the toxicity of the product itself, which is independent of the variables affecting the individual [2]. A good example is acetaminophen, also known as Tylenol, APAP and Panadol. At normal dosages in normal situations it can be cleared by the body without toxicity, however at excessive dosages APAP is toxic and leads to liver injury [3].

  1. IdiosyncraticHerb Induced Liver Injury
    1. Unpredictable.
    2. Does not depend on dose.
    3. Long and variable latency period.
    4. Variable liver injury types.
    5. Low incidence in humans.
    6. Lack of experimental reproducibility.

  1. IntrinsicHerb Induced Liver Injury
    1. Predictable.
    2. Clear dependence on dose.
    3. Short, and consistent latency period.
    4. Distinctive liver injury patterns.
    5. High incidence in humans.
    6. Can be reproduced in an experiment.

When an herb is suspected of causing liver injury it is placed in one of the two groups above. Further classification of idiosyncratic types are metabolic and immunologic types of injury. Metabolic idiosyncrasy involves liver injury due to metabolic pathway interruption (CYP) [4], whereas the immunologic type of injury involves immune system and inflammatory activities more related to allergy. [5].

  1. Metabolic Type
    1. Duration of exposure requires 1 week to several months
    2. Lack of hypersensitivity features
    3. Delayed response to reexposure in the time frame of weeks

  1. Immunologic Type
    1. Duration of exposure: few weeks
    2. Hypersensitivity features
    3. Prompt response to exposure with 1 or 2 doses.

Now let’s establish what exactly is meant by “liver damage” and how these researchers are able to say this. It turns out that there are several familiar classifications with one new one, adaptive change. It’s important to note that no liver damage diagnosis can be given without a proper metabolic test which looks at levels of AST/ALT/ALP/GGT and/or bilirubin. Also, liver toxicity and adaptation cannot be claimed until the noted levels below are reached.

Liver Changes:

  1. Adaptive: Sometimes misdiagnosed as liver injury or hepatotoxicity. Liver adaptation or tolerance in connection with herbal uses represents mild modification of liver integrity due to metabolic interactions between chemicals and the liver, as evidenced by small increases in liver tests. Going back a little bit to kava, GGT has been seen as an adaptive change in the presence of kava, and this is considered a normal function seen with adaptive changes in the liver [6].
    1. ALT values are less than 5 times the upper limit of normal
    2. ALP values are less than 2 times the upper limit of normal
    3. Develops at recommended daily dosages

  1. Idiosyncratic: The liver injury ascribed to the interactions between the phytochemical in question and the patient’s own individual factors.
    1. ALT is less than or equal to 5 times the upper limit of normal.
    2. ALP is less than or equal to 2 times the upper limit of normal.
    3. Develops at recommended daily dosages.

  1. Intrinsic: Toxicity related to the herb itself.
    1. ALT is greater than or equal to 5 times the upper limit of normal.
    2. ALP is greater than or equal to 2 times the upper limit of normal.
    3. Emerges quickly after acute herbal overdose [7]

Tea, the drink consumed by billions of people around the world, is prepared from the leaves of the plant Camellia sinensis. The most well known types are black, oolong, and green tea with black tea being the most consumed (80% of the market). Besides the caffeine and theobromine type alkaloids, the polyphenols are considered to be the major active molecules in tea. These are known as catechins, and of the ones found in tea, EGCG is the most abundant and possesses the highest antioxidant potential [8]. EGCG has been preliminarily shown to protect against various types of cancers to small degrees [9,11], and aids in weight loss [3] however the science on cancer prevention with ordinary tea is contested [12]. Research on EGCG from natural sources in the diet have been met with limited success and some evidence of liver enzyme elevation has been observed [13]. Along with instances of liver test abnormalities, liver damage and necrosis have occurred [14]. Since 1966 at least 216 case reports of green tea extract toxicity exist. It was found that doses of EGCG as little as 5.9g over 5 days to a maximum of 240g over 120 days may be harmful [15].

Obviously we know that green tea is not a ubiquitous liver poison and never has been, so what’s really going on here? What these researchers tell us is that green tea extracts, in parallel to kava extracts, can cause extremely rare idiosyncratic liver reactions in some individuals. It shows us that idiosyncratic reactions are isolated, can have serious or benign outcomes, and can happen with an enormous array of herbs and drugs. Even with positive proof of this reaction from EGCG, we still see no warnings issued for its consumption. When you buy a bottle of green tea from the gas station there is no liver warning on the side of the product. With kava we don’t even have that positive proof. Studies regarding kava’s possible hepatotoxicity have all come up empty-handed with only suggestions as to what could be occurring. I postulate that the idiosyncratic issues with green tea as a beverage are on the same level of those seen with kava as a beverage, and as such both neither have a reason for concern to the general population. In the same vein extracts of herbal products should be viewed with a degree of scrutiny. When it comes to quality, it seems that using it how nature made it gives us the best and safest option for consumption.

Quick Summary:
There are more well documented cases of liver injury from green tea and green tea extracts than there are from kava by a large margin. No liver warning exists for green tea, and no general understanding of risk is held by the consumer base related to any toxicity by green tea. Injuries by herbs can be boiled down into two types, toxicity of the herb itself, and toxicity of the herb when in the presence of people with certain issues that are not compatible, also known as idiosyncrasies. I theorize that kava as a beverage, having fewer incidences of idiosyncratic injury (most likely being immunologic aka “allergy”), as well as no evidence supporting intrinsic toxicity, is as safe or safer than green tea for the liver, and we know that green tea is safe.

[1] Chalasani, Naga, and Einar Björnsson. 2010. “Risk Factors for Idiosyncratic Drug-Induced Liver Injury.” Gastroenterology 138 (7): 2246–59. https://doi.org/10.1053/j.gastro.2010.04.001

[2] Lin, Nai-Hui, Hsiu-Wu Yang, Yu-Jang Su, and Chen-Wang Chang. 2019. “Herb Induced Liver Injury after Using Herbal Medicine: A Systemic Review and Case-Control Study.” Medicine 98 (13): e14992. https://doi.org/10.1097/MD.0000000000014992

[3] Larson, Anne M. 2007. “Acetaminophen Hepatotoxicity.” Clinics in Liver Disease 11 (3): 525–48, vi. https://doi.org/10.1016/j.cld.2007.06.006

[4] Uetrecht, Jack, and Dean J. Naisbitt. 2013. “Idiosyncratic Adverse Drug Reactions: Current Concepts.” Pharmacological Reviews 65 (2): 779–808. https://doi.org/10.1124/pr.113.007450

[5] Mak, Alastair, and Jack Uetrecht. 2017. “Immune Mechanisms of Idiosyncratic Drug-Induced Liver Injury.” Translational Research: The Journal of Laboratory and Clinical Medicine 3 (1): 145–56. https://www.ncbi.nlm.nih.gov/pubmed/30873473

[6] Everhart, James E., and Elizabeth C. Wright. 2013. “Association of γ-Glutamyl Transferase (GGT) Activity with Treatment and Clinical Outcomes in Chronic Hepatitis C (HCV).” Hepatology 57 (5): 1725–33. https://doi.org/10.1002/hep.26203

[7] Teschke, R., and T. D. Xuan. 2019. “Suspected Herb Induced Liver Injury by Green Tea Extracts: Critical Review and Case Analysis Applying RUCAM for Causality Assessment.” Japanese Journal of Gastroenterology and Hepatology.

[8] Mazzanti, Gabriela, Antonella Di Sotto, and Annabella Vitalone. 2015. “Hepatotoxicity of Green Tea: An Update.” Archives of Toxicology 89 (8): 1175–91. https://doi.org/10.1007/s00204-015-1521-x

[9] Du, Guang-Jian, Zhiyu Zhang, Xiao-Dong Wen, Chunhao Yu, Tyler Calway, Chun-Su Yuan, and Chong-Zhi Wang. 2012. “Epigallocatechin Gallate (EGCG) Is the Most Effective Cancer Chemopreventive Polyphenol in Green Tea.” Nutrients 4 (11): 1679–91. https://doi.org/10.3390/nu4111679

[10] Chen, I-Ju, Chia-Yu Liu, Jung-Peng Chiu, and Chung-Hua Hsu. 2016. “Therapeutic Effect of High-Dose Green Tea Extract on Weight Reduction: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial.” Clinical Nutrition 35 (3): 592–99. https://doi.org/10.1016/j.clnu.2015.05.003

[11] Yuan, Jian-Min. 2013. “Cancer Prevention by Green Tea: Evidence from Epidemiologic Studies.” The American Journal of Clinical Nutrition 98 (6 Suppl): 1676S – 1681S. https://doi.org/10.3945/ajcn.113.058271

[12] Eisenstein, Michael. 2019. “Tea’s Value as a Cancer Therapy Is Steeped in Uncertainty.” Nature 566 (7742): S6–7. https://doi.org/10.1038/d41586-019-00397-2

[13] Yu, Zheming, Hamed Samavat, Allison M. Dostal, Renwei Wang, Carolyn J. Torkelson, Chung S. Yang, Lesley M. Butler, et al. 2017. “Effect of Green Tea Supplements on Liver Enzyme Elevation: Results from a Randomized Intervention Study in the United States.” Cancer Prevention Research 10 (10): 571–79. https://doi.org/10.1158/1940-6207.CAPR-17-0160

[14] Patel, Shreena S., Stacey Beer, Debra L. Kearney, Garrett Phillips, and Beth A. Carter. 2013. “Green Tea Extract: A Potential Cause of Acute Liver Failure.” World Journal of Gastroenterology: WJG 19 (31): 5174–77. https://doi.org/10.3748/wjg.v19.i31.5174

[15] Navarro, Victor J., Herbert L. Bonkovsky, Sun-Il Hwang, Maricruz Vega, Huiman Barnhart, and Jose Serrano. 2013. “Catechins in Dietary Supplements and Hepatotoxicity.” Digestive Diseases and Sciences 58 (9): 2682–90. https://doi.org/10.1007/s10620-013-2687-9


Magnum's 'awa drinking bird
... which makes every ban on kava even more ridiculous and reveals the despotism of some countries and pharmaceutical industries.

As always, thanks for the extensive report!