Risk of Liver Injury Associated with Green Tea Extract in SLIMQUICK(®) Weight Loss Products: Results from the DILIN Prospective Study

Estimated Exposure to 6 Potentially Hepatotoxic Botanicals in US Adults

Importance

Use of herbal and dietary supplements (HDSs) accounts for an increasing proportion of drug hepatotoxicity cases. Turmeric or curcumin, green tea extract, Garcinia cambogia, black cohosh, red yeast rice, and ashwagandha are the most frequently reported hepatoxic botanicals, but their prevalence and reasons for use in the general population are unknown.

Objective

To assess the prevalence and clinical characteristics of adult consumers of 6 potentially hepatoxic botanicals.

Design, Setting, and Participants

This survey study analyzed nationally representative data from the National Health and Nutrition Examination Survey (NHANES), a nationally representative, cross-sectional survey of the general US population. Prescription drug and HDS exposure data in the past 30 days were analyzed, and 2020 US Census data were used for population estimates. Data were analyzed July 1, 2023, to February 1, 2024.

Exposures

Adult NHANES participants enrolled between January 2017 and March 2020.

Main Outcomes and Measures

Baseline weighted characteristics of HDS users and users of 6 potentially hepatotoxic botanical products were compared with non-HDS users. Multivariable analysis was undertaken to identify factors associated with HDS use or at-risk botanical use.

Results

Among 9685 adults enrolled in this NHANES cohort, the mean (SE) age was 47.5 (0.5) years, and 51.8% (95% CI, 50.2%-53.4%) were female. The overall prevalence of HDS product use was 57.6% (95% CI, 55.9%-59.4%), while the prevalence of using the 6 botanicals of interest was 4.7% (95% CI, 3.9%-5.7%). Turmeric-containing botanicals were most commonly used (n = 236), followed by products containing green tea (n = 92), ashwagandha (n = 28), Garcinia cambogia (n = 20), red yeast rice (n = 20), and black cohosh (n = 19). Consumers of these 6 botanicals were significantly older (adjusted odds ratio [AOR], 2.36 [95% CI, 1.06-5.25]; P = .04 for 40-59 years of age and AOR, 3.96 [95% CI, 1.93-8.11]; P = .001 for ≥60 years of age), had a higher educational level (AOR, 4.78 [95% CI, 2.62-8.75]; P < .001), and were more likely to have arthritis (AOR, 2.27 [95% CI, 1.62-3.29]; P < .001) compared with non-HDS users. An estimated 15 584 599 (95% CI, 13 047 571-18 648 801) US adults used at least 1 of the 6 botanical products within the past 30 days, which was similar to the estimated number of patients prescribed potentially hepatotoxic drugs, including simvastatin (14 036 024 [95% CI, 11 202 460-17 594 452]) and nonsteroidal anti-inflammatory drugs (14 793 837 [95% CI, 13 014 623-16 671 897]). The most common reason for consuming turmeric and green tea was to improve or maintain health.

Conclusions and Relevance

In this survey study, an estimated 15.6 million US adults consumed at least 1 botanical product with liver liability within the past 30 days, comparable with the number of people who consumed nonsteroidal anti-inflammatory drugs and a commonly prescribed hypolipidemic drug. Given a lack of regulatory oversight on the manufacturing and testing of botanical products, clinicians should be aware of possible adverse events from consumption of these largely unregulated products.

Liver Damage and microRNAs: An Update

One of the major organs in the body with multiple functions is the liver. It plays a central role in the transformation of macronutrients and clearance of chemicals and drugs. The serum biomarkers often used to indicate liver damage are not specifically for drug-induced liver injury (DILI) or liver injury caused by other xenobiotics, nor for viral infection. In this case, microRNAs (miRNAs) could play an exciting role as biomarkers of specific liver damage. In this review, we aimed to update the current literature on liver damage induced by drugs, as acute conditions and viral infections mediated by the hepatitis B virus (HBV) linked these two conditions to advanced research, with a focus on microRNAs as early biomarkers for liver damage. The undoubtable evidence that circulating miR-122 could be used as a human biomarker of DILI came from several studies in which a strong increase of it was linked with the status of liver function. In infancy, there is the possibility of an early miRNA detection for hepatitis B virus infection, but there are a lack of solid models for studying the HVB molecular mechanism of infection in detail, even if miRNAs do hold unrealized potential as biomarkers for early detection of hepatitis B virus infection mediated by HBV.

Epigallocatechin gallate as a nutraceutical to potentially target the metabolic syndrome: novel insights into therapeutic effects beyond its antioxidant and anti-inflammatory properties

Epigallocatechin gallate (EGCG) is one of the most abundant and powerful flavonoids contained in green tea. Because of the global increase in green tea consumption, there has been a general interest in understanding its health benefits, including its bioactive compounds like EGCG. Indeed, preclinical evidence already indicates that EGCG demonstrated a strong antioxidant and anti-inflammatory properties that could be essential in protecting against metabolic syndrome. The current review explores clinical evidence reporting on the beneficial effects of EGCG supplementation in obese subjects or patients with diverse metabolic complications that include type 2 diabetes and cardiovascular disease. The discussion incorporates the impact of different formulations of EGCG, as well as the effective doses and treatment duration. Importantly, besides highlighting the potential use of EGCG as a nutraceutical, the current review also discusses crucial evidence related to its pharmaceutical development as an agent to hinder metabolic diseases, including its bioavailability and metabolism profile, as well as its well-known biological properties.

Causality imputation between herbal products and HILI: An algorithm evaluation in a systematic review

Algorithms can have several purposes in the clinical practice. There are different scales for causality imputation in DILI (Drug-Induced Liver Injury), but the applicability and validity of these for the HILI (Herb-Induced Liver Injury) evaluation is questionable for some scales. The purpose of the study was to determine the clinical and demographic profile of the patients with HILI, and the main algorithmic scales used in its causality assessment. The methodology was a systematic review of articles in English, Spanish, or Portuguese language, from 1979 to 2019, involving humans, with descriptors related to HILI. Qualitative and quantitative statistical analysis were performed. As a result, from a total of 60 articles, 203 HILI reports were selected: 59.9% were women, similar with other studies, and the average age was 45.8 years. Jaundice was the most frequent symptom and regarding the type of lesion, the hepatocellular was the most frequent. In regard to HILI severity, 3.0% were severe and 7.6% were fatal or required liver transplantation. In 72.3% of the cases, the most used algorithm was RUCAM (Roussel Uclaf Causality Assessment Method). The conclusion of the study is that RUCAM was the most used algorithm for causality assessment in HILI. The patients were predominantly female, jaundice was the main symptom, and HILI is reversible in the majority of cases.

HLA-B*35:01 and Green Tea-Induced Liver Injury

BACKGROUND AND AIMS

Herbal supplements, and particularly multi-ingredient products, have become increasingly common causes of acute liver injury. Green tea is a frequent component in implicated products, but its role in liver injury is controversial. The aim of this study was to better characterize the clinical features, outcomes, and pathogenesis of green tea-associated liver injury.

APPROACH AND RESULTS

Among 1,414 patients enrolled in the U.S. Drug-Induced Liver Injury Network who underwent formal causality assessment, 40 cases (3%) were attributed to green tea, 202 to dietary supplements without green tea, and 1,142 to conventional drugs. The clinical features of green tea cases and representation of human leukocyte antigen (HLA) class I and II alleles in cases and control were analyzed in detail. Patients with green tea-associated liver injury ranged in age from 17 to 69 years (median = 40) and developed symptoms 15-448 days (median = 72) after starting the implicated agent. The liver injury was typically hepatocellular (95%) with marked serum aminotransferase elevations and only modest increases in alkaline phosphatase. Most patients were jaundiced (83%) and symptomatic (88%). The course was judged as severe in 14 patients (35%), necessitating liver transplantation in 3 (8%), but rarely resulting in chronic injury (3%). In three instances, injury recurred upon re-exposure to green tea with similar clinical features, but shorter time to onset. HLA typing revealed a high prevalence of HLA-B*35:01, found in 72% (95% confidence interval [CI], 58-87) of green tea cases, but only 15% (95% CI, 10-20) caused by other supplements and 12% (95% CI, 10-14) attributed to drugs, the latter rate being similar to population controls (11%; 95% CI, 10.5-11.5).

CONCLUSIONS

Green tea-related liver injury has distinctive clinical features and close association with HLA-B*35:01, suggesting that it is idiosyncratic and immune mediated.

Liver Injury Caused by Green Tea Extract in PD-1-/- Mice: An Impaired Immune Tolerance Model for Idiosyncratic Drug-Induced Liver Injury

Idiosyncratic drug-induced liver injury (IDILI) is an idiosyncratic drug reaction that is specific to an individual and can lead to liver failure and even death. The mechanism of IDILI remains poorly understood, but most IDILI appears to be immune-mediated. We have developed the first validated animal model by using a PD-1^-/- mouse model in combination with anti-CTLA-4 to block immune checkpoints and impair immune tolerance. Treatment of these mice with drugs that cause IDILI in humans led to delayed-onset liver injury with characteristics similar to IDILI in humans. The current study investigates the effects of green tea extract, a weight-loss dietary supplement that has been reported to cause IDILI in humans. Green tea extracts contain a highly variable content of catechins including (-)-epigallocatechin gallate, the major catechin in green tea formulations. If the liver injury caused by green tea extract in humans is immune-mediated, it may occur in our impaired immune tolerance model. Female PD-1^-/- mice treated with anti-CTLA-4 antibody and green tea extract (500 mg/kg), a dose that is considered a no-observed-adverse-effect level for liver in rodents, produced a delayed onset increase in serum alanine transaminase levels and an increase in hepatic CD8⁺ T cells. In contrast, the response in male PD-1^-/- mice was less pronounced, and there was no evidence of liver injury in wild-type mice. These findings are consistent with the hypothesis that the IDILI caused by green tea extract is immune-mediated and is similar to IDILI caused by medications that are associated with IDILI.

Epigallocatechin Gallate During Dietary Restriction - Potential Mechanisms of Enhanced Liver Injury

Green tea extract (GTE) is popular in weight loss, and epigallocatechin gallate (EGCG) is considered as the main active component. However, GTE is the primary cause of herbal and dietary supplement-induced liver injury in the United States. Whether there is a greater risk of liver injury when EGCG is consumed during dieting for weight loss has not been previously reported. This study found for the first time that EGCG could induce enhanced lipid metabolism pathways, suggesting that EGCG had the so-called “fat burning” effect, although EGCG did not cause liver injury at doses of 400 or 800 mg/kg in normal mice. Intriguingly, we found that EGCG caused dose-dependent hepatotoxicity on mice under dietary restriction, suggesting the potential combination effects of dietary restriction and EGCG. The combination effect between EGCG and dietary restriction led to overactivation of linoleic acid and arachidonic acid oxidation pathways, significantly increasing the accumulation of pro-inflammatory lipid metabolites and thus mediating liver injury. We also found that the disruption of Lands’ cycle and sphingomyelin-ceramides cycle and the high expression of taurine-conjugated bile acids were important metabolomic characteristics in EGCG-induced liver injury under dietary restriction. This original discovery suggests that people should not go on a diet while consuming EGCG for weight loss; otherwise the risk of liver injury will be significantly increased. This discovery provides new evidence for understanding the “drug-host” interaction hypothesis of drug hepatotoxicity and provides experimental reference for clinical safe use of green tea-related dietary supplements.

Potential Modulation of Human NAD[P]H-Quinone Oxidoreductase 1 (NQO1) by EGCG and Its Metabolites-A Systematic Computational Study

At high doses, green tea extracts and green tea's major active constituent, (-)-epigallocatechin gallate (EGCG), despite their generally perceived health benefits, have been suspected to cause hepatotoxicity in certain human populations. It has been reported that o-quinone metabolites of gallic acid or EGCG are causative agents for this hepatotoxicity. However, no experimental information is available at the molecular level on the possible role of NQO1 in the detoxification of EGCG and its metabolites, including reactive intermediates. In the present study, we investigated the possibility of NQO1 inhibition by EGCG and its metabolites by studying their interaction profiles and binding mechanism at the active site of NQO1 using molecular docking, binding free energy calculations, and molecular dynamics (MD) simulations. The binding free energy calculations showed that some metabolites exhibited strong predicted binding affinity and found that the binding orientation of the EGCG metabolites overlapped with that of dicoumarol found in an NQO1 X-ray crystal structure. The results suggest that these metabolites may act as strong NQO1 inhibitors, highlighting the need for experimental validation of this with appropriate biological methods. The Prime MM-GBSA computed average binding free energies after MD simulations of compounds 1, 2, 24, 31, and 33 revealed that these compounds highly favored van der Waals (VdW) and Coulombic interactions with NQO1. In addition, the MD results revealed that selected EGCG metabolites formed a stable and strong complex with NQO1, with amino acids W105, Y126, Y128, H161, F178, H194, F232, and F236 being critical for potential NQO1 binding. The current results together with experimental data as well as studies of the polymorphisms of NQO1 (especially C609T) may explain the observed idiosyncratic hepatotoxicity caused by the consumption of green tea and its constituents.

Disintegration and Dissolution Testing of Green Tea Dietary Supplements: Application and Evaluation of United States Pharmacopeial Standards

Approved performance quality tests are lacking in the United States Pharmacopeia (USP) for dietary supplements (DSs) containing green tea extracts. We evaluated the applicability of USP <2040 > general chapter protocols for disintegration and dissolution testing of botanicals to GT DSs. Of 28 single-ingredient GT DSs tested in 2 to 4 lots, 9 (32.1%) always passed the disintegration test, 8 (28.6%) always failed, and 11 (39.3%) showed inconsistent results. Of 34 multi-ingredient DSs tested in 2 lots, 21 (61.8%) passed and 8 (23.5%) failed in both lots, and 5 (14.7%) exhibited inconsistent performance. When stronger destructive forces were applied (disk added), all of the capsules that had failed initially, but not the tablets, passed. In dissolution testing, for the release of epigallocatechin-3-gallate (EGCG), only 6 of 20 single-ingredient DSs passed. Unexpectedly, with the addition of pepsin (prescribed by USP), only one additional DS passed. These results raise concerns that EGCG was not released properly from GT DS dosage forms. However, the general USP protocols may be inadequate for this botanical. More biorelevant destructive forces may be needed to break down capsules and tablets strengthened by the EGCG's interaction with shell material and to overcome the inhibition of digestive enzymes by EGCG.

Drug-induced Liver Injury Secondary to Herbal and Dietary Supplements

The use of herbal and dietary supplements (HDS) is increasing in the United States and worldwide. Its significant association with liver injury has become a concern, particularly because rates of hepatotoxicity caused by HDS are increasing. There are variety of HDS available, ranging from multi-ingredient substances, to anabolic steroids for bodybuilding purposes, to individual ingredients for purposes of supplementing a diet. This article reviews the impact of liver injury cause by HDS and explores the hepatotoxic potential of such products and their individual ingredients.

High Dietary Kuding Tea Extract Supplementation Induces Hepatic Xenobiotic-Metabolizing Enzymes-A 6-Week Feeding Study in Mice

Kuding tea (KT) is a traditional Chinese beverage rich in plant bioactives that may exhibit various health benefits. However, little is known about the safety of KT extract (KTE) when consumed long term at high doses as a dietary supplement. Therefore, in this study, we investigated aspects of the safety of KTE. Male C57BL/6 mice were fed a high-fat, high-fructose, Western-type diet (control) supplemented with either 12.88% γ-cyclodextrin (γCD), 7.12% KTE (comprising 0.15% ursolic acid, UA) encapsulated in 12.88% γCD (KTE-γCD), or 0.15% UA over a 6-week experimental period. The dietary treatments did not affect food intake, body weight or body composition. However, treatment with KTE-γCD, but not γCD and UA, increased liver weight and hepatic fat accumulation, which was accompanied by increased hepatic PPARγ and CD36 mRNA levels. KTE-γCD treatment elevated plasma cholesterol and CYP7A1 mRNA and protein levels compared to those in control mice. KTE-γCD substantially increased the mRNA and protein levels of hepatic CYP3A and GSTA1, which are central to the detoxification of drugs and xenobiotics. Furthermore, we observed a moderate elevation in hepatic CYP3A (5-fold change) and GSTA1 (1.7-fold change) mRNA levels in UA-fed mice. In vitro data collected in HepG2 cells indicated a dose-dependent increase in hepatic cytotoxicity in response to KTE treatment, which may have been partly mediated by UA. Overall, the present data may contribute to the safety assessment of KTE and suggest that KTE encapsulated in γCD affects liver fat storage and the hepatic phase I and phase II responses in mice.

Severe liver injury due to herbal and dietary supplements and the role of liver transplantation

Herbal and dietary supplements (HDS) are increasingly used worldwide for numerous, mainly unproven health benefits. The HDS industry is poorly regulated compared to prescription medicines and most products are easily obtainable. Drug induced liver injury (DILI) is a well-recognized entity associated with prescription and over the counter medications and many reports have emerged of potential HDS-related DILI. There is considerable geographic variability in the risk and severity of DILI associated with HDS but the presentation of severe liver injury is similar with a hepatocellular pattern accompanied by jaundice. This type of injury can lead to acute liver failure and the need for liver transplantation. Patients will often fail to mention their use of HDS, considering it natural and therefore harmless. Hence physicians should understand that these products can be associated with DILI and explicitly ask about HDS use in any patient with otherwise unexplained acute liver injury.

Suspected adverse reactions associated with herbal products used for weight loss: spontaneous reports from the Italian Phytovigilance System

PURPOSE

Overweight and obesity represent worldwide a rising health problem. In this context, dietary supplements and herbal preparations are often used as self-medication for weight loss. The aim of this study was to describe the safety profile of dietary supplements for weight control by analyzing spontaneous reports of suspected adverse reactions (ARs) received by the Italian Phytovigilance System, from July 2010 to October 2017.

METHODS

The suspected ARs were collected using an ad hoc reporting form, registered in a database at the National Institute of Health and evaluated by a multidisciplinary group of experts. The causality assessment was performed using the WHO-UMC system or the CIOMS/RUCAM score. In case of serious adverse reactions, a feedback is provided to the reporter by e-mail.

RESULTS

Sixty-six spontaneous reports were collected. ARs involved cardiovascular system (26%), liver (14%), central nervous system (12%), skin (9%), gastrointestinal system (17%), thyroid (8%), kidney (4%), and other organs/systems (10%). In 64% of cases, the reaction was serious. Dechallenge was positive in 46 cases; three cases of positive rechallenge were reported. After the causality assessment, the association between the product intake and the adverse reaction was judged as possible in the majority of the cases (n = 43; 65%).

CONCLUSIONS

The data collected confirmed the existence of safety concerns on herbal dietary supplements used for body weight control, mainly related to quality of products and their use as self-medication. In this scenario, spontaneous reports represent the only tools available to monitor safety of these products.

Scientific opinion on the safety of green tea catechins

The EFSA ANS Panel was asked to provide a scientific opinion on the safety of green tea catechins from dietary sources including preparations such as food supplements and infusions. Green tea is produced from the leaves of Camellia sinensis (L.) Kuntze, without fermentation, which prevents the oxidation of polyphenolic components. Most of the polyphenols in green tea are catechins. The Panel considered the possible association between the consumption of (-)-epigallocatechin-3-gallate (EGCG), the most relevant catechin in green tea, and hepatotoxicity. This scientific opinion is based on published scientific literature, including interventional studies, monographs and reports by national and international authorities and data received following a public 'Call for data'. The mean daily intake of EGCG resulting from the consumption of green tea infusions ranges from 90 to 300 mg/day while exposure by high-level consumers is estimated to be up to 866 mg EGCG/day, in the adult population in the EU. Food supplements containing green tea catechins provide a daily dose of EGCG in the range of 5-1,000 mg/day, for adult population. The Panel concluded that catechins from green tea infusion, prepared in a traditional way, and reconstituted drinks with an equivalent composition to traditional green tea infusions, are in general considered to be safe according to the presumption of safety approach provided the intake corresponds to reported intakes in European Member States. However, rare cases of liver injury have been reported after consumption of green tea infusions, most probably due to an idiosyncratic reaction. Based on the available data on the potential adverse effects of green tea catechins on the liver, the Panel concluded that there is evidence from interventional clinical trials that intake of doses equal or above 800 mg EGCG/day taken as a food supplement has been shown to induce a statistically significant increase of serum transaminases in treated subjects compared to control.

Safety assessment of green tea based beverages and dried green tea extracts as nutritional supplements

The safety of green tea infusions and green tea extract (GTE)-based products is reviewed regarding catechins. Epigallocatechin 3-gallate (EGCG), the major catechin present in green tea, is suspected of being responsible for liver toxicity reported in humans consuming food supplements. Intake of EGCG with green tea infusions and GTE-based beverages is up to about 450mg EGCG/person/day in Europe and higher in Asia. Consumption of green tea is not associated with liver damage in humans, and green tea infusion and GTE-based beverages are considered safe in the range of historical uses. In animal studies, EGCG's potency for liver effects is highly dependent on conditions of administration. Use of NOAELs from bolus administration to derive a tolerable upper intake level applying the margin of safety concept results in acceptable EGCG-doses lower than those from one cup of green tea. NOAELs from toxicity studies applying EGCG with diet/split of the daily dose are a better point of departure for risk characterization. In clinical intervention studies, liver effects were not observed after intakes below 600mg EGCG/person/day. Thus, a tolerable upper intake level of 300mg EGCG/person/day is proposed for food supplements; this gives a twofold safety margin to clinical studies that did not report liver effects and a margin of safety of 100 to the NOAELs in animal studies with dietary administration of green tea catechins.