Effects of coffee consumption in chronic hepatitis C: a randomized controlled trial

Causal associations between chronic viral hepatitis and psychiatric disorders: a Mendelian randomization study

Background

There may be an interaction between viral hepatitis and psychiatric disorders during disease progression. Herein, we conducted Mendelian randomization (MR) to explore the causal associations and mediators between viral hepatitis and psychiatric disorders.

Methods

Genome-wide association studies summary data for viral hepatitis [including chronic hepatitis B (CHB) and chronic hepatitis C (CHC)] and psychiatric disorders (including depression, anxiety, schizophrenia, obsessive-compulsive disorder, bipolar disorder, and post-traumatic stress disorder) were obtained. Two-sample MR was performed to assess the causal associations between viral hepatitis and psychiatric disorders. Further, a mediation analysis was conducted to evaluate the potential mediators. Inverse-variance weighted, MR-Egger, and weighted median were used as the main methods, while a sensitivity analysis was performed to evaluate pleiotropy and heterogeneity.

Results

There was no causal effect of CHB/CHC on psychiatric disorders, as well as psychiatric disorders on CHB. However, schizophrenia presented a causal effect on increased CHC risk [odds ratio (OR)=1.378, 95%CI: 1.012-1.876]. Further, a mediation analysis identified coffee consumption and body mass index as mediators in the effect of schizophrenia on CHC, mediating 3.75% (95%CI: 0.76%-7.04%) and 0.94% (95%CI: 0.00%-1.70%) proportion, respectively.

Conclusion

We revealed that schizophrenia patients faced a high risk of CHC, and insufficient coffee consumption and underweight could mediate the causal effect of schizophrenia on CHC. The prevention of hepatitis C might be a beneficial strategy for patients with schizophrenia. The right amount of nutrition supplements and coffee consumption might be part of a beneficial lifestyle in preventing the high CHC risk in patients with schizophrenia.

Inverted U-shaped relationship between coffee consumption and serum uric acid in American chronic kidney disease population

Objective

The objective of this study was to examine the contentious relationship between coffee consumption and serum uric acid (SUA) levels, specifically within American population with chronic kidney disease (CKD).

Methods

A total of 23,381 participants from the 2001-2018 National Health and Nutrition Examination Survey (NHANES) were selected for inclusion in this investigation. Linear regression models and generalized additive models with smooth curve fitting were employed to analyze the association between log coffee consumption and serum uric acid levels. Furthermore, the robustness of the findings was assessed across diverse populations.

Results

The results of the linear regression analysis indicate a positive and marginally statistically significant (p = 0.0307) association between log coffee consumption and SUA, even after controlling for other variables. Furthermore, the generalized additive model revealed a nonlinear relationship characterized by an inverted U-shape between log coffee consumption and SUA. The inflection point, identified as 11.43 g/day, marks the point at which this relationship changes direction. Moreover, this inverted U-shaped relationship was consistently observed across various subgroups, including gender, age (<60 and ≥ 60 years), hypertensive and non-hypertensive individuals, those with and without cardiovascular disease, non-diabetic individuals, and those who consumed coffee with or without caffeine or sugar.

Conclusion

An inverse U-shaped correlation has been observed between log coffee consumption and SUA levels. This finding implies that once coffee consumption surpasses a specific threshold, it promotes a decline in SUA levels.

Instant Coffee Is Negatively Associated with Telomere Length: Finding from Observational and Mendelian Randomization Analyses of UK Biobank

Telomere length, as a biomarker of accelerated aging, is closely related to many chronic diseases. We aimed to explore the association between coffee consumption and telomere length. Our study included 468,924 participants from the UK Biobank. Multivariate linear models (observational analyses) were conducted to evaluate the associations of coffee intake, instant coffee intake, and filtered coffee intake with telomere length. In addition, we evaluated the causality of these associations in Mendelian randomization (MR) analyses by four methods (inverse-variance weighted (IVW), MR pleiotropy residual sum and outlier (MR-PRESSO), MR-Egger, and weighted median). Observational analyses indicated that coffee intake and instant coffee intake were negatively correlated with telomere length, which was equal to 0.12 year of age-related decrease in telomere length for each additional cup of coffee intake (p < 0.001), and 0.38 year of age-related decrease in telomere length for each additional cup of instant coffee intake (p < 0.001), respectively. There was no significant correlation between filtered coffee and telomere length (p = 0.862). Mendelian randomization analyses supported the results of observational analyses. Coffee intake was found to have a causal effect on telomere length through weighted median analysis (p = 0.022), and instant coffee intake had a causal effect on telomere length through IVW analysis (p = 0.019) and MR-PRESSO analysis (p = 0.028). No causal relationship was found between filtered coffee intake and telomere length (p > 0.05). Coffee intake, particularly instant coffee, was found to have an important role in shortening telomere length.

Coffee Consumption Is Associated With Lower Liver Stiffness: A Nationally Representative Study

BACKGROUND & AIMS

Coffee is associated with a reduced risk of liver disease. This association is limited by important sources of confounding such as recall bias, healthy user bias, and indirect measures of liver outcomes or health. We aimed to examine the impact of coffee consumption with liver fibrosis and steatosis in a nationally representative sample.

METHODS

We evaluated 4510 subjects 20 years and older from the 2017 to 2018 National Health and Nutrition Examination Survey study who underwent both transient elastography and two 24-hour dietary recall examinations. We tested the associations between liver stiffness measurements (LSM) of 9.5 kpa or greater or controlled attenuation parameter (CAP) and coffee consumption. We used decaffeinated coffee and tea consumption as controls. As a sensitivity analysis, we included all drinks in 1 model, examined the impact of caffeine consumption, and adjusted for the Healthy Eating Index-2015 and sugar-sweetened beverage consumption as separate models.

RESULTS

The study sample described was aged 48 ± 0.6 years, 73% were overweight or obese, 10.6% had diabetes, 47.5% reported participation in vigorous physical activity, and 23% drank 2 or more alcoholic drinks per day. After multivariate adjustment, there was no association between coffee and controls with CAP. Subjects who drank more than 3 cups of coffee, but not other drinks, had a 0.9 lower kPa (95% CI, -1.6 to -0.1; P = .03). More than 3 cups of coffee were protective for LSM of 9.5 kpa or higher (odds ratio, 0.4; 95% CI, 0.2-1.0; P = .05). Accounting for all beverages in the same model, only consuming more than 3 cups of coffee remained independently associated with LSM (odds ratio, 0.5; 95% CI, 0.2-0.9; P = .03). Caffeine was not associated significantly with LSM at any dose. Finally, adjusting for sugar-sweetened beverage consumption and Healthy Eating Index-2015, coffee consumption remained associated with a lower LSM. The protective nature of coffee consumption therefore is not attributable to caffeine and persists in participants regardless of their diet quality.

CONCLUSIONS

Coffee is associated with lower liver stiffness, but not steatosis, as measured by CAP among US adults.

Effect of Coffee and Cocoa-Based Confectionery Containing Coffee on Markers of DNA Damage and Lipid Peroxidation Products: Results from a Human Intervention Study

The effect of coffee and cocoa on oxidative damage to macromolecules has been investigated in several studies, often with controversial results. This study aimed to investigate the effect of one-month consumption of different doses of coffee or cocoa-based products containing coffee on markers of DNA damage and lipid peroxidation in young healthy volunteers. Twenty-one volunteers were randomly assigned into a three-arm, crossover, randomized trial. Subjects were assigned to consume one of the three following treatments: one cup of espresso coffee/day (1C), three cups of espresso coffee/day (3C), and one cup of espresso coffee plus two cocoa-based products containing coffee (PC) twice per day for 1 month. At the end of each treatment, blood samples were collected for the analysis of endogenous and H2O2-induced DNA damage and DNA oxidation catabolites, while urines were used for the analysis of oxylipins. On the whole, four DNA catabolites (cyclic guanosine monophosphate (cGMP), 8-OH-2'-deoxy-guanosine, 8-OH-guanine, and 8-NO2-cGMP) were detected in plasma samples following the one-month intervention. No significant modulation of DNA and lipid damage markers was documented among groups, apart from an effect of time for DNA strand breaks and some markers of lipid peroxidation. In conclusion, the consumption of coffee and cocoa-based confectionery containing coffee was apparently not able to affect oxidative stress markers. More studies are encouraged to better explain the findings obtained and to understand the impact of different dosages of these products on specific target groups.

Coffee Extends Yeast Chronological Lifespan through Antioxidant Properties

Aging is a multifactorial process accompanied by loss of cell function. Science has been looking for factors responsible for aging for many years. However, despite identifying a number of possible causes, the definite reason for aging has been elusive so far. One of the factors contributing to aging is oxygen free radicals. In this context, beneficial effects of coffee on various organisms, including humans, were investigated, although the results are far from unequivocal. In our research, we used the budding yeast-something of a workhorse in many studies, including the studies of aging. So far, the impact of coffee on the aging of cells in the budding yeast experimental setup has little known about it. Here, we provide strong evidence that coffee compounds, particularly flavonoids, are responsible for scavenging free radicals and longevity in yeast lacking Sod1, Sod2 and Rad52 proteins. In this paper, we compared Arabica and Robusta coffee types. We present an analysis of the concentration of caffeine and flavonoids measured by the High-Performance Liquid Chromatography method. We show that Robusta has a much greater antioxidant capacity than Arabica. We also conclude that coffee infusions significantly extend the chronological lifespan of the Saccharomyces cerevisiae yeast cells by protecting cells against reactive oxygen species, double DNA-strand break and decrease in metabolic activity.

Impact of Nutrition on Telomere Health: Systematic Review of Observational Cohort Studies and Randomized Clinical Trials

Diet, physical activity, and other lifestyle factors have been implicated in the pathophysiology of several chronic diseases, but also in a lower total mortality and longer life expectancy. One of the mechanisms in which diet can reduce the risk of disease is with regard to its impact on telomeres. Telomere length (TL) is highly correlated to chronological age and metabolic status. Individuals with shorter telomeres are at higher risk of chronic diseases and mortality. Diet may influence TL by several mechanisms such as regulating oxidative stress and inflammation or modulating epigenetic reactions. The present systematic review aims to examine the results from epidemiologic and clinical trials conducted in humans evaluating the role of nutrients, food groups, and dietary patterns on TL. We also discuss the possible mechanisms of action that influence this process, with the perspective that TL could be a novel biomarker indicating the risk of metabolic disturbances and age-related diseases. The available evidence suggests that some antioxidant nutrients, the consumption of fruits and vegetables, and Mediterranean diet are mainly associated with longer telomeres. However, most of the evidence is based on high heterogenic observational studies and very few randomized clinical trials (RCTs). Therefore, the associations summarized in the present review need to be confirmed with larger prospective cohort studies and better-designed RCTs.

Association between coffee drinking and telomere length in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

Mounting evidence indicates that coffee, a commonly consumed beverage worldwide, is inversely associated with various chronic diseases and overall mortality. Few studies have evaluated the effect of coffee drinking on telomere length, a biomarker of chromosomal integrity, and results have been inconsistent. Understanding this association may provide mechanistic insight into associations of coffee with health. The aim of our study was to test the hypothesis that heavier coffee intake is associated with greater likelihood of having above-median telomere length. We evaluated the cross-sectional association between coffee intake and relative telomere length using data from 1,638 controls from four previously conducted case-control studies nested in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Coffee intake was assessed using a food frequency questionnaire, and relative telomere length was measured from buffy-coat, blood, or buccal cells. We used unconditional logistic regression models to generate multivariable-adjusted, study-specific odds ratios for the association between coffee intake and relative telomere length. We then conducted a random-effects meta-analysis to determine summary odds ratios. We found that neither summary continuous (OR = 1.01, 95% CI = 0.99-1.03) nor categorical (OR <3 cups/day vs. none = 1.37, 95% CI = 0.71-2.65; OR ≥3 cups/day vs. none = 1.47, 95% CI = 0.81-2.66) odds ratio estimates of coffee drinking and relative telomere length were statistically significant. However, in the largest of the four contributing studies, moderate (<3 cups/day) and heavy coffee drinkers (≥3 cups/day) were 2.10 times (95% CI = 1.25, 3.54) and 1.93 times as likely (95% CI = 1.17, 3.18) as nondrinkers to have above-median telomere length, respectively. In conclusion, we found no evidence that coffee drinking is associated with telomere length. Thus, it is unlikely that telomere length plays a role in potential coffee-disease associations.

Interventions targeted at oxidatively generated modifications of nucleic acids focused on urine and plasma markers

Oxidative stress is associated with the development and progression of numerous diseases. However, targeting oxidative stress has not been established in the clinical management of any disease. Several methods and markers are available to measure oxidative stress, including direct measurement of free radicals, antioxidants, redox balance, and oxidative modifications of cellular macromolecules. Oxidatively generated nucleic acid modifications have attracted much interest due to the pre-mutagenic oxidative modification of DNA into 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), associated with cancer development. During the last decade, the perception of RNA has changed from that of a 'silent messenger' to an 'active contributor', and, parallelly oxidatively generated RNA modifications measured as 8-oxo-7,8-dihydro-guanosine (8-oxoGuo), has been demonstrated as a prognostic factor for all-caused and cardiovascular related mortality in patients with type 2 diabetes. Several attempts have been made to modify the amount of oxidative nucleic acid modifications. Thus, this review aims to introduce researchers to the measurement of oxidatively generated nucleic acid modifications as well as critically review previous attempts and provide future directions for targeting oxidatively generated nucleic acid modifications.

Relationship between Telomere Length, Genetic Traits and Environmental/Occupational Exposures in Bladder Cancer Risk by Structural Equation Modelling

Background: Telomere length (TL) maintenance plays an important role in bladder cancer (BC) and prognosis. However the manifold influence of everyday life exposures and genetic traits on leucocyte TL (LTL), is not fully elucidated. Methods: Within the framework of a hospital-based case (n = 96)/control (n = 94) study (all Caucasian males), we investigated the extent to which LTL and BC risk were modulated by genetic polymorphisms and environmental and occupational exposures. Data on lifetime smoking, alcohol and coffee drinking, dietary habits and occupational exposures, pointing to aromatic amines (AAs) and polycyclic aromatic hydrocarbons (PAHs) were collected. Structural equation modelling (SEM) analysis appraised this complex relationships. Results: The SEM analysis indicates negative direct links (p < 0.05) between LTL with age, DNA adducts, alcohol and NAT2, and positive ones with coffee, MPO and XRCC3; and between BC risk (p < 0.01) with cigarettes, cumulative exposure to AAs and coffee, while are negative with LTL and age. There was evidence of indirect effects (p < 0.05) on BC risk, probably via LTL reduction, by age and NAT2 (positive link), MPO and XRCC3 (negative link).

CONCLUSIONS

Our study supports evidence that LTL attrition is a critical event in BC. The new finding that LTL erosion depends on some preventable everyday life exposures genetically modulated, opens new perspectives in BC prevention.

Coffee: The magical bean for liver diseases

Coffee has long been recognized as having hepatoprotective properties, however, the extent of any beneficial effect is still being elucidated. Coffee appears to reduce risk of hepatocellular carcinoma, reduce advancement of fibrotic disease in a variety of chronic liver diseases, and perhaps reduce ability of hepatitis C virus to replicate. This review aims to catalog the evidence for coffee as universally beneficial across a spectrum of chronic liver diseases, as well as spotlight opportunities for future investigation into coffee and liver disease.

Effects of caffeine consumption in patients with chronic hepatitis C: A systematic review and meta-analysis

BACKGROUND

Increased caffeine consumption has been associated with a decreased risk of liver enzyme elevation, cirrhosis, and hepatocellular carcinoma. However, few studies have assessed these effects in patients with chronic hepatitis C; therefore, we conducted a systematic review and meta-analysis to investigate the impact of caffeine consumption in patients with chronic hepatitis C infection.

METHODS

We performed a comprehensive search of the databases of the Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE from inception through November 2015. The inclusion criterion was observational studies' assessment of the impact of caffeine consumption in adult patients with chronic hepatitis C.

RESULTS

Eleven studies were included for full article review, and data was extracted from five observational studies for meta-analysis. The pooled odds ratio of advanced hepatic fibrosis in patients who had higher caffeine intake was 0.39 (95% confidence interval 0.21-0.72, P=0.003) compared with lower caffeine intake group. The statistical between-study heterogeneity was moderate with an I² of 70%.

CONCLUSIONS

Our meta-analysis demonstrated that caffeine intake is significantly associated with decreased odds of advanced hepatic fibrosis in patients with chronic hepatitis C. Future prospective studies assessing the optimal dose and preparation of caffeinated beverages for prevention of hepatic fibrosis are needed.

Molecular Bases Underlying the Hepatoprotective Effects of Coffee

Coffee is the most consumed beverage worldwide. Epidemiological studies with prospective cohorts showed that coffee intake is associated with reduced cardiovascular and all-cause mortality independently of caffeine content. Cohort and case-control studies reported an inverse association between coffee consumption and the degree of liver fibrosis as well as the development of liver cancer. Furthermore, the beneficial effects of coffee have been recently confirmed by large meta-analyses. In the last two decades, various in vitro and in vivo studies evaluated the molecular determinants for the hepatoprotective effects of coffee. In the present article, we aimed to critically review experimental evidence regarding the active components and the molecular bases underlying the beneficial role of coffee against chronic liver diseases. Almost all studies highlighted the beneficial effects of this beverage against liver fibrosis with the most solid results indicating a pivot role for both caffeine and chlorogenic acids. In particular, in experimental models of fibrosis, caffeine was shown to inhibit hepatic stellate cell activation by blocking adenosine receptors, and emerging evidence indicated that caffeine may also favorably impact angiogenesis and hepatic hemodynamics. On the other side, chlorogenic acids, potent phenolic antioxidants, suppress liver fibrogenesis and carcinogenesis by reducing oxidative stress and counteract steatogenesis through the modulation of glucose and lipid homeostasis in the liver. Overall, these molecular insights may have translational significance and suggest that coffee components need clinical evaluation.

Coffee Intake Is Associated with a Lower Liver Stiffness in Patients with Non-Alcoholic Fatty Liver Disease, Hepatitis C, and Hepatitis B

There is emerging evidence for the positive effects or benefits of coffee in patients with liver disease. We conducted a retrospective cross-sectional study on patients with non-alcoholic fatty liver disease (NAFLD), hepatitis C virus (HCV), and hepatitis B virus (HBV) infection to determine the effects of coffee intake on a non-invasive marker of liver fibrosis: liver stiffness assessed by transient elastography (TE). We assessed coffee and tea intake and measured TE in 1018 patients with NAFLD, HCV, and HBV (155 with NAFLD, 378 with HCV and 485 with HBV). Univariate and multivariate regression models were performed taking into account potential confounders. Liver stiffness was higher in males compared to females (p < 0.05). Patients with HBV had lower liver stiffness than those with HCV and NAFLD. After adjustment for age, gender, smoking, alcohol consumption, M or XL probe, and disease state (NAFLD, HCV, and HBV status), those who drank 2 or more cups of coffee per day had a lower liver stiffness (p = 0.044). Tea consumption had no effect (p = 0.9). Coffee consumption decreases liver stiffness, which may indicate less fibrosis and inflammation, independent of disease state. This study adds further evidence to the notion of coffee maybe beneficial in patients with liver disease.

The antifibrotic and fibrolytic properties of date fruit extract via modulation of genotoxicity, tissue-inhibitor of metalloproteinases and nuclear factor- kappa B pathway in a rat model of hepatotoxicity

BACKGROUND

Hepatic fibrosis and its end point; cirrhosis, are the major cause of liver failure and death in patients with chronic liver disease. Therefore, the need for an effective treatment is evident. This study was designed to assess the potential effects of aqueous extract of date fruits, either flesh (DFE) or pits (DPE), on oxidative DNA damage and liver inflammation induced by carbon tetrachloride (CCl4) and whether they are related to inhibition of nuclear factor-κB pathway. In addition, the fibrolytic potential was evaluated via measuring matrix metalloproteinase-9 and tissue inhibitor of metalloproteinases -1 and -2.

METHODS

Rats were divided into the following groups: normal control, model control (CCl4 only), CCl4 + DFE, CCl4 + DPE and CCl4 + coffee. Coffee was used as a positive control. Fibrosis was induced by chronic administration of CCl4 (0.4 ml/kg) 3× a week for 8 weeks, and rats were treated with 6 ml/kg/day of DFE or DPE for 8 weeks. Liver homogenate was prepared for evaluation of oxidative stress, DNA damage, inflammatory and fibrolytic markers. Data are analyzed using one-way analysis of variance followed by a Tukey-Kramer post hoc test.

RESULTS

Both DFE and DPE significantly attenuated CCl4-induced oxidative damage as indicated by reducing lipid, protein and DNA oxidation in addition to increasing the levels of hepatic catalase activity. Both extracts blocked the accumulation of collagen I in the liver and ameliorated the increased expression of collagen III and α-smooth muscle actin suggesting suppression of profibrotic response induced by CCl4. DFE and DPE also upregulated the expression of heme oxygenase-1 and attenuated the nuclear factor-κB activation and cycloxygenase-2 expression reflecting their anti-inflammatory potential. Additionally, both flesh and pits extracts attenuated the increase in the tissue inhibitor of metalloproteinases -1 and -2 suggesting their fibrolytic activity.

CONCLUSION

Our data suggest that DFE or DPE can prevent liver fibrosis by suppressing genotoxicity and nuclear factor-κB inflammatory pathway and by promoting collagen degradation.

Coffee Consumption and Oxidative Stress: A Review of Human Intervention Studies

Research on the potential protective effects of coffee and its bioactives (caffeine, chlorogenic acids and diterpenes) against oxidative stress and related chronic disease risk has been increasing in the last years. The present review summarizes the main findings on the effect of coffee consumption on protection against lipid, protein and DNA damage, as well as on the modulation of antioxidant capacity and antioxidant enzymes in human studies. Twenty-six dietary intervention studies (involving acute and chronic coffee intake) have been considered. Overall, the results suggest that coffee consumption can increase glutathione levels and improve protection against DNA damage, especially following regular/repeated intake. On the contrary, the effects of coffee on plasma antioxidant capacity and antioxidant enzymes, as well as on protein and lipid damage, are unclear following both acute and chronic exposure. The high heterogeneity in terms of type of coffee, doses and duration of the studies, the lack of information on coffee and/or brew bioactive composition, as well as the choice of biomarkers and the methods used for their evaluation, may partially explain the variability observed among findings. More robust and well-controlled intervention studies are necessary for a thorough understanding of the effect of coffee on oxidative stress markers in humans.

Coffee Consumption Is Positively Associated with Longer Leukocyte Telomere Length in the Nurses' Health Study

BACKGROUND

Coffee is an important source of antioxidants, and consumption of this beverage is associated with many health conditions and a lower mortality risk. However, no study, to our knowledge, has examined whether varying coffee or caffeine consumption levels are associated with telomere length, a biomarker of aging whose shortening can be accelerated by oxidative stress.

OBJECTIVE

We performed a large comprehensive study on how coffee consumption is associated with telomere length.

METHODS

We used data from the Nurses' Health Study (NHS), a prospective cohort study of female nurses that began in 1976. We examined the cross-sectional association between coffee consumption and telomere length in 4780 women from the NHS. Coffee consumption information was obtained from validated food-frequency questionnaires, and relative telomere length was measured in peripheral blood leukocytes by the quantitative real-time polymerase chain reaction. Unconditional logistic regression was used to obtain ORs when the telomere length outcome was dichotomized at the median. Linear regression was used for tests of trend with coffee consumption and telomere length as continuous variables.

RESULTS

Higher total coffee consumption was significantly associated with longer telomeres after potential confounding adjustment. Compared with non-coffee drinkers, multivariable ORs for those drinking 2 to <3 and ≥3 cups of coffee/d were, respectively, 1.29 (95% CI: 0.99, 1.68) and 1.36 (95% CI: 1.04, 1.78) (P-trend = 0.02). We found a significant linear association between caffeine consumption from all dietary sources and telomere length (P-trend = 0.02) after adjusting for potential confounders, but not after additionally adjusting for total coffee consumption (P-trend = 0.37).

CONCLUSIONS

We found that higher coffee consumption is associated with longer telomeres among female nurses. Future studies are needed to better understand the influence of coffee consumption on telomeres, which may uncover new knowledge of how coffee consumption affects health and longevity.

Coffee and Liver Disease

Coffee is the most popular beverage in the world. Consumption of coffee has been shown to benefit health in general, and liver health in particular. This article reviews the effects of coffee intake on development and progression of liver disease due to various causes. We also describe the putative mechanisms by which coffee exerts the protective effect. The clinical evidence of benefit of coffee consumption in Hepatitis B and C, as well as nonalcoholic fatty liver disease and alcoholic liver disease, has also been presented. Coffee consumption is associated with improvement in liver enzymes (ALT, AST, and GGTP), especially in individuals with risk for liver disease. Coffee intake more than 2 cups per day in patients with preexisting liver disease has been shown to be associated with lower incidence of fibrosis and cirrhosis, lower hepatocellular carcinoma rates, as well as decreased mortality.

Systematic review with meta-analysis: coffee consumption and the risk of cirrhosis

BACKGROUND

Liver cirrhosis is a large burden on global health, causing over one million deaths per year. Observational studies have reported an inverse association between coffee and cirrhosis.

AIMS

To perform a systematic review and meta-analysis to characterise the relationship between coffee consumption and cirrhosis.

METHODS

We searched for studies published until July 2015 that reported odds ratios, relative risks (RR) or hazard ratios for cirrhosis stratified by coffee consumption. We calculated RRs of cirrhosis for an increase in daily coffee consumption of two cups for each study and overall. We performed analyses by study design, type of cirrhosis and mortality. We assessed the risk of bias in each study and the overall quality of evidence for the effect of coffee on cirrhosis.

RESULTS

We identified five cohort studies and four case-control studies involving 1990 cases and 432 133 participants. We observed a dose-response in most studies and overall. The pooled RR of cirrhosis for a daily increase in coffee consumption of two cups was 0.56 (95% CI 0.44-0.68; I(2) 83.3%). The RR pooled from cohort studies for a daily increase of two cups was 0.58 (95% CI 0.41-0.76; I(2) 91.1%) and from case-control studies it was 0.52 (95% CI 0.40-0.63; I(2) 0.0%). The pooled RR of alcoholic cirrhosis for a daily increase of two cups was 0.62 (95% CI 0.51-0.73; I(2) 0%) and of death from cirrhosis it was 0.55 (95% CI 0.35-0.74; I(2) 90.3%).

CONCLUSION

This meta-analysis suggests that increasing coffee consumption may substantially reduce the risk of cirrhosis.

I drink for my liver, Doc: emerging evidence that coffee prevents cirrhosis

Evidence demonstrating that regular ingestion of coffee has salutary effects on patients with chronic liver disease is accumulating rapidly. Specifically, it appears that coffee ingestion can slow the progression of liver fibrosis, preventing cirrhosis and hepatocellular carcinoma (HCC). This should excite clinicians and scientists alike, since these observations, if true, would create effective, testable hypotheses that should lead to improved understanding on fibrosis pathogenesis and thus may generate novel pharmacologic treatments of patients with chronic liver disease.

This review is designed to examine the relevant clinical and epidemiological data in critical fashion and to examine the putative pharmacological effects of coffee relevant to the pathogenesis of liver fibrosis and cirrhosis. We hope that this will inspire relevant critical analyses, especially among “coffee skeptics”. Of note, one major assumption made by this review is that the bulk of the effects of coffee consumption are mediated by caffeine, rather than by other chemical constituents of coffee. Our rationales for this assumption are threefold: first, caffeine’s effects on adenosinergic signaling provide testable hypotheses; second, although there are  myriad chemical constituents of coffee, they are present in very low concentrations, and perhaps more importantly, vary greatly between coffee products and production methods (it is important to note that we do not dismiss the “botanical” hypothesis here; rather, we do not emphasize it at present due to the limitations of the studies examined); lastly, some (but not all) observational studies have examined both coffee and non-coffee caffeine consumption and found consistent effects, and when examined, no benefit to decaffeinated coffee has been observed. Further, in the interval since we examined this phenomenon last, further evidence has accumulated supporting caffeine as the effector molecule for coffee’s salutary effects.

Antioxidant property of coffee components: assessment of methods that define mechanisms of action

Coffee is a rich source of dietary antioxidants, and this property, coupled with the fact that coffee is one of the world's most popular beverages, has led to the understanding that coffee is a major contributor to dietary antioxidant intake. Brewed coffee is a complex food matrix with numerous phytochemical components that have antioxidant activity capable of scavenging free radicals, donating hydrogen and electrons, providing reducing activity and also acting as metal ion pro-oxidant chelators. More recent studies have shown that coffee components can trigger tissue antioxidant gene expression and protect against gastrointestinal oxidative stress. This paper will describe different in vitro, cell-free and cell-based assays that both characterize and compare the antioxidant capacity and mechanism of action of coffee and its bioactive constituents. Moreover, evidence of cellular antioxidant activity and correlated specific genomic events induced by coffee components, which are relevant to antioxidant function in both animal and human studies, will be discussed.

Coffee and liver health

Coffee is one of the most widely used beverages in the world. It includes a wide array of components that can have potential implications for health. Several epidemiological studies associate coffee consumption with a reduced incidence of various chronic diseases such as diabetes, cardiovascular diseases, and neurodegenerative diseases. Over the past 20 years, an increasing number of epidemiological and experimental studies have demonstrated the positive effects of coffee on chronic liver diseases. Coffee consumption has been inversely associated with the activity of liver enzymes in subjects at risk, including heavy drinkers. Coffee favours an improvement in hepatic steatosis and fibrosis, and a reduction in cirrhosis and the risk of hepatocellular carcinoma. The mechanisms of action through which it exerts its beneficial effects are not fully understood. Experimental studies show that coffee consumption reduces fat accumulation and collagen deposition in the liver and promotes antioxidant capacity through an increase in glutathione as well as modulation of the gene and protein expression of several inflammatory mediators. Animal and in vitro studies indicate that cafestol and kahweol, 2 diterpens, can operate by modulating multiple enzymes involved in the detoxification process of carcinogens causing hepatocellular carcinoma. It is unclear whether the benefits are significant enough to "treat" patients with chronic liver disease. While we await clarification, moderate daily unsweetened coffee use is a reasonable adjuvant to therapy for these patients.