ECGC (green tea extract) toxicity & copper relationship

[cs3000]

Small amounts of these compounds act as positive eustressors, not toxic enough to do damage but enough to activate protective mechanisms that gives outweighing benefits. but best to be mindful of good doses for flavanols polyphenols catechins etc as too much can tip the balance into toxicity

EGCG green tea extract is a common supp sold in the 100s of milligrams per dose. high enough to cause liver damage. 15g of 70% dark chocolate should give ~10mg catechins which is a safer amount.

u dont want 100s of milligrams of catechins, maybe unless you have high copper levels supporting this
Supposedly 270mg can cause liver damage / failure Hepatotoxicity of green tea: an update - PubMed

Dietary Copper Reduces the Hepatotoxicity of (−)-Epigallocatechin-3-Gallate in Mice

We developed Cu-deficient, -sufficient and -super nutrition mice models by feeding them with diet containing 1.68, 11.72 or 51.69 mg of Cu/kg for 28 days, respectively. Then, the mice were treated to (−)-epigallocatechin-3-gallate (EGCG, 750 mg/kg ...

www.ncbi.nlm.nih.gov

^ toxicity is determined by copper intake / ceruloplasmin level. higher copper = becomes less or non toxic

(do low dose catechins stimulate copper absorption as a response which is why some studies show cocoa raising copper in smaller doses than copper supplements?)
^ EGCG increases ceruloplasmin activity on copper sufficient or overload diet, but not on deficient diet (implies more need for it & upregulated absorption but in the deficient diet there's not enough intake to enhance absorption of?)

Recognition of these effects and related cytotoxicity has suggested a significant role of EGCG in cancer therapy, as well as potential negative consequences on healthy cells, particularly in the liver [70,71,72,73,74,75]. However, at lower biologic concentrations (1 μM up to 10 μM) EGCG produces smaller amounts of intracellular ROS that stimulate multiple pathways to promote cellular protective mechanisms, supporting the idea that activation of signaling cascades may, at least in part, depend on EGCG-mediated ROS production

Green tea catechins were widely studied because of their potential benefits on human health [5]. (−)-Epigallocatechin-3-gallate (EGCG), the predominant component among catechins, can prevent certain types of chronic diseases including cancer, obesity, type-2 diabetes, lipid metabolism abnormity, atherosclerosis, and other cardiovascular diseases [6]. Intriguingly, EGCG can also undergo auto-oxidation to generate reactive oxygen species (ROS). At physiological dose, the moderate pro-oxidant action of EGCG induces adaptive responses with the gain of enhanced and prolonged antioxidant and detoxifying capacities, which has been regarded as an important mechanism for many of the beneficial biological functions of EGCG [7].

However, many researchers have reported that high doses of green tea extract or EGCG can induce hepatotoxicity. A study has revealed that high dose of EGCG caused hepatotoxicity and even death in mice [8]. The oral administration of EGCG at dose of 2000 mg/kg induced 80% mortality [9]. Green tea polyphenols, containing 90% EGCG, induced toxicity and even death in Beagle dogs [10]. Consumption of the green tea extract at high doses (expressed as EGCG 270 and 400 mg/day) caused hepatotoxicity in human beings [11,12,13]. Moreover, green tea hepatotoxicity is greatly enhanced when it is consumed in association with other herbal or dietary ingredients [13]. However, the melatonin attenuated EGCG-triggered hepatotoxicity and reduced hepatic Nrf2 activation [12], suggesting that there exist some factors that can affect EGCG hepatotoxicity.


In the present study, we elucidated that diverse Cu levels can cure the high dose EGCG toxicity in animals.
EGCG toxicity (750 mg/kg) was enhanced in Cu-deficient mice leading to severe death; however, all mice survived in Cu-super nutrition mice

(typo in title, EGCG)