Herbal Medicine: U.S Scientists Warns That Green Tea Is Hepatoxic To Those With UGT1A4 Gene Variants!

Herbal Medicine: There is a common fallacy that herbs and traditional medicine involving only plants and phytochemicals are basically harmless and safe and hence one should not worry about consuming them. In reality, many herbs and phytochemicals if used wrongly can actually not only exacerbate conditions that they are used to treat but also give rise to other medical conditions and in some cases can even cause fatal outcomes. Many herbs contain toxic alkaloids and other phytochemicals that cause harm to the human body and worse, many herbs in the market are not properly pre-treated and even contain carcinogenic fungi in them! Furthermore, human genetics also play a critical role if critical phytochemicals can be properly metabolized and serve their beneficial roles or if they pose as toxic threats.


 
High dose green tea extract in recent times have been promoted with claims that it may provide some protection against cancer, cardiovascular disease, obesity. type 2 diabetes and even help with COVID-19 and Long COVID.
 
However, unknown to many, consumption of greet tea or green tea extract supplements can actually harm the liver and cause a variety of liver issues in a high proportion of individuals.
 
Researchers from the Department of Clinical and Preventive Nutrition Sciences, Rutgers University School of Health Professions - USA and the Department of Food Science and Nutrition, University of Minnesota – USA have found that green tea is actually hepatoxic to individuals with UGT1A4 (Uridine 5’-Diphospho-glucuronosyltransferase 1A4) gene variants.
 
The study findings confirmed that the predominant catechin in green tea, epigallocatechin gallate (EGCG), may be hepatotoxic in high doses.
 
The study team’s objective was to investigate the influence of catechol-O-methyltransferase (COMT) and uridine 5’-diphospho-glucuronosyltransferase 1A4 (UGT1A4) genotypes on changes in liver injury biomarkers in response to long-term, high-dose green tea extract (GTE) supplementation among postmenopausal women.
 
A further secondary analysis was conducted using data from the Minnesota Green Tea Trial (N = 1,075), in which participants were randomized to consume high-dose GTE (843 mg/day EGCG) or placebo capsules for 12 months.
 
Analysis of covariance adjusting for potential confounders was performed to examine changes in aspartate aminotransferase (AST), alanine aminotransferase (ALT), AST: ALT ratio, and alkaline phosphatase from baseline to months 3, 6, 9, and 12 across COMT and UGT1A4 genotypes. Mean age and BMI within the GTE group (n = 400) were 59.8 yrs and 25.1 kg/m2, respectively, and 98% of subjects were white.
 
The study findings showed that from baseline to month 3, mean AST: ALT ratio change was +1.0% in the COMT (rs4680) A/G genotype versus −4.8% in the A/A genotype (p = 0.03). From baseline to months 6 and 9, respectively, mean ALT change was +78.1% and +82.1% in the UGT1A4 (rs6755571) A/C genotype versus +28.0% and +30.1% in the C/C genotype (p < 0.001 a nd p = 0.004, respectively).
 
Importantly, the study findings showed that UGT1A4 (rs6755571) A/C genotype may be an important risk factor for clinically-relevant serum transaminase elevations with 6-9 months of high-dose GTE supplementation among postmenopausal women.
 
Comprehending the genetic underpinnings of GTE-related hepatotoxicity may allow for a genetically-informed paradigm for therapeutic use of GTE.
 
The study findings were published in the peer reviewed Journal Of Dietary Supplements.
https://www.tandfonline.com/doi/abs/10.1080/19390211.2022.2128501
 
The study findings show that long-term use of high-dose green tea extract may create liver damage in those with UGT1A4 (rs6755571) A/C genotype.
 
Senior author, Dr Hamed Samavat, an assistant professor of nutrition sciences at the Rutgers School of Health Professions told Herbal Medicine reporters at Thailand Medical News, "Learning to predict who will suffer liver damage is potentially important because there's growing evidence that high-dose green tea extract may have significant health benefits for those who can safely take it."
 
Utilizing data from the Minnesota Green Tea Trial, a large study of green tea's effect on breast cancer, the study team investigated whether individuals with certain genetic variations were more likely than others to show signs of liver stress after a year of ingesting 843 milligrams per day of the predominant antioxidant in green tea, a catechin called epigallocatechin gallate (EGCG).
 
The study team led by Dr Laura Acosta, then a doctoral student Rutgers University School of Health Professions, now a graduate, selected two genetic variations in question because each controls the synthesis of an enzyme that breaks EGCG down. They selected the Minnesota Green Tea Trial because it was a large, well-designed study of a unique population. The year-long, placebo-controlled trial included more than 1,000 postmenopausal women and collected data at 3, 6, 9 and 12 months.
 
The study findings showed that early signs of liver damage were somewhat more common than normal in women with one variation in the catechol-O-methyltransferase (COMT) genotype and strongly predicted by a variation in the uridine 5'-diphospho-glucuronosyltransferase 1A4 (UGT1A4) genotype.
 
Interestingly, on average, participants with the high-risk UGT1A4 genotype saw the enzyme that indicates liver stress go up nearly 80 percent after nine months of consuming the green tea supplement, while those with low-risk genotypes saw the same enzyme go up 30 percent.
 
Dr Samavat, who noted the risk of liver toxicity is only associated with high levels of green tea supplements and not with drinking green tea or even taking lower doses of green tea extract further added, "We're still a long way from being able to predict who can safely take high-dose green tea extract. Variations in this one genotype don't completely explain the variations in liver enzyme changes among study participants. The full explanation probably includes a number of different genetic variations and probably a number of non-genetic factors."
 
He added, "Still, we do think we have identified an important piece of the puzzle and taken a step toward predicting who can safely enjoy any health benefits that high-dose green tea extract provides."
 
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