Coffee Consumption and the Progression of NAFLD: A Systematic Review

Caffeic acid ameliorates metabolic dysfunction-associated steatotic liver disease via alleviating oxidative damage and lipid accumulation in hepatocytes through activating Nrf2 via targeting Keap1

Metabolic-associated steatotic liver disease (MASLD), known as non-alcoholic fatty liver disease (NAFLD) in the past, encompasses a range of liver pathological conditions marked by the excessive lipid accumulation. Consumption of coffee is closely associated with the reduced risk of MASLD. Caffeic acid (CA), a key active ingredient in coffee, exhibits notable hepatoprotective properties. This study aims to investigate the improvement of CA on MASLD and the engaged mechanism. Mice underwent a 12-week high-fat diet (HFD) regimen to induce MASLD, and liver pathology was assessed using hematoxylin-eosin (H&E) and oil red O (ORO) staining. Hepatic inflammation was evaluated by F4/80 and Ly6G immunohistochemistry (IHC) and myeloperoxidase (MPO) measurement. Pathways and transcription factors relevant to MASLD were analyzed by using microarray data from patients' livers. Oxidative damage was evaluated by detecting reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD). Co-immunoprecipitation (CoIP), cellular thermal shift assay (CETSA) and surface plasmon resonance (SPR) were used to validate the binding between CA and its target protein. CA significantly alleviated liver damage, steatosis and inflammatory injury, and reduced the elevated NAFLD activity score (NAS) in HFD-fed mice. Clinical data indicate that fatty acid metabolism and ROS generation are pivotal in MASLD progression. CA increased the expression of fibroblast growth factor 21 (FGF21), FGF receptor 1 (FGFR1) and β-Klotho (KLB), and promoted fatty acid consumption. Additionally, CA mitigated oxidative stress injury and activated nuclear factor erythroid 2-related factor-2 (Nrf2). In primary hepatocytes isolated from Nrf2 knockout mice, CA's promotion on FGF21 release and inhibition on oxidative stress and lipotoxicity was disappeared. CA could directly bind to kelch-like ECH-associated protein 1 (Keap1) that is an Nrf2 inhibitor protein. This study suggests that CA alleviates MASLD by reducing hepatic lipid accumulation, lipotoxicity and oxidative damage through activating Nrf2 via binding to Keap1.

Protective Effect of Caffeine and Chlorogenic Acids of Coffee in Liver Disease

Coffee is one of the most widely consumed beverages in the world due to its unique aroma and psychostimulant effects, mainly due to the presence of caffeine. In recent years, experimental evidence has shown that the moderate consumption of coffee (3/4 cups per day) is safe and beneficial to human health, revealing protective effects against numerous chronic metabolic diseases such as diabetes, cardiovascular, neurodegenerative, and hepatic diseases. This review focuses on two of coffee's main bioactive compounds, i.e., caffeine and chlorogenic acids, and their effects on the progression of chronic liver diseases, demonstrating that regular coffee consumption correlates with a lower risk of the development and progression of non-alcoholic steatohepatitis, viral hepatitis, liver cirrhosis, and hepatocellular carcinoma. In particular, this review analyzes caffeine and chlorogenic acid from a pharmacological point of view and explores the molecular mechanism through which these compounds are responsible for the protective role of coffee. Both bioactive compounds, therefore, have antifibrotic effects on hepatic stellate cells and hepatocytes, induce a decrease in connective tissue growth factor, stimulate increased apoptosis with anti-cancer effects, and promote a major inhibition of focal adhesion kinase, actin, and protocollagen synthesis. In conclusion, coffee shows many beneficial effects, and experimental data in favor of coffee consumption in patients with liver diseases are encouraging, but further prospective studies are needed to demonstrate its preventive and therapeutic role in chronic liver diseases.

Preventive effects of caffeine on nicotine plus high-fat diet-induced hepatic steatosis and gain weight: a possible explanation for why obese smokers with high coffee consumption tend to be leaner

Non-alcoholic fatty liver disease (NAFLD) is a prevalent liver disorder, affecting approximately 25 % of the population. Coffee-drinking obese smokers exhibit lower body weights and decreased NAFLD rates, but the reasons behind this remain unclear. Additionally, the effect of nicotine, the main component of tobacco, on the development of NAFLD is still controversial. Our study aimed to explore the possible reasons that drinking coffee could alleviate NAFLD and gain weight and identify the real role of nicotine in NAFLD of obese smokers. A NAFLD model in mice was induced by administering nicotine and a high-fat diet (HFD). We recorded changes in body weight and daily food intake, measured the weights of the liver and visceral fat, and observed liver and adipose tissue histopathology. Lipid levels, liver function, liver malondialdehyde (MDA), superoxide dismutase (SOD), serum inflammatory cytokine levels and the expression of hepatic genes involved in lipid metabolism were determined. Our results demonstrated that nicotine exacerbated the development of NAFLD and caffeine had a hepatoprotective effect on NAFLD. The administration of caffeine could ameliorate nicotine-plus-HFD-induced NAFLD by reducing lipid accumulation, regulating hepatic lipid metabolism, alleviating oxidative stress, attenuating inflammatory response and restoring hepatic functions. These results might explain why obese smokers with high coffee consumption exhibit the lower incidence rate of NAFLD and tend to be leaner. It is essential to emphasise that the detrimental impact of smoking on health is multifaceted. Smoking cessation remains the sole practical and effective strategy for averting the tobacco-related complications and reducing the risk of mortality.

Different Associations of Coffee Consumption with the Risk of Incident Metabolic Dysfunction-Associated Steatotic Liver Disease and Advanced Liver Fibrosis

Although coffee has a potential hepatoprotective effect, evidence of the relationship between coffee consumption and metabolic dysfunction-associated steatotic liver disease (MASLD) remains conflicting. There is limited evidence regarding the most appropriate coffee intake to prevent advanced liver fibrosis (ALF) in patients with MASLD. We investigated the effect of coffee consumption on MASLD and ALF among 5266 participants without MASLD and 1326 with MASLD but without ALF. Participants were grouped by coffee intake: non-consumers, >0 and <1 cups/day, ≥1 and <2 cups/day, and ≥2 cups/day. Over a median follow-up of 11.6 years for MASLD and 15.7 years for ALF, coffee consumption did not significantly affect the incidence of MASLD, with 2298 new cases observed. However, a notable inverse association was found with ALF risk in patients with MASLD among those consuming coffee ≥2 cups/day (adjusted HR 0.57, 95% CI: 0.37-0.90, p = 0.014), especially among those consuming coffee ≥2 and <3 cups/day (adjusted HR 0.51, 95% CI: 0.30-0.89, p = 0.018). This suggests a potential hepatoprotective effect of coffee, especially in preventing the progression of liver fibrosis in patients with MASLD. These findings propose that coffee consumption could be a simple and effective approach to mitigate the risk of ALF in individuals with MASLD.

Potential Therapeutic Strategies in the Treatment of Metabolic-Associated Fatty Liver Disease

Metabolic-associated Fatty Liver Disease is one of the outstanding challenges in gastroenterology. The increasing incidence of the disease is undoubtedly connected with the ongoing obesity pandemic. The lack of specific symptoms in the early phases and the grave complications of the disease require an active approach to prompt diagnosis and treatment. Therapeutic lifestyle changes should be introduced in a great majority of patients; but, in many cases, the adherence is not satisfactory. There is a great need for an effective pharmacological therapy for Metabolic-Associated Fatty Liver Disease, especially before the onset of steatohepatitis. Currently, there are no specific recommendations on the selection of drugs to treat liver steatosis and prevent patients from progression toward more advanced stages (steatohepatitis, cirrhosis, and cancer). Therefore, in this Review, we provide data on the clinical efficacy of therapeutic interventions that might improve the course of Metabolic-Associated Fatty Liver Disease. These include the drugs used in the treatment of obesity and hyperlipidemias, as well as affecting the gut microbiota and endocrine system, and other experimental approaches, including functional foods. Finally, we provide advice on the selection of drugs for patients with concomitant Metabolic-Associated Fatty Liver Disease.

Sugar-Sweetened Beverages and Artificially Sweetened Beverages Consumption and the Risk of Nonalcoholic Fatty Liver (NAFLD) and Nonalcoholic Steatohepatitis (NASH)

Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) are fast becoming the most common chronic liver disease and are often preventable with healthy dietary habits and weight management. Sugar-sweetened beverage (SSB) consumption is associated with obesity and NAFLD. However, the impact of different types of SSBs, including artificially sweetened beverages (ASBs), is not clear after controlling for total sugar intake and total caloric intake. The aim of this study was to examine the association between the consumption of different SSBs and the risk of NAFLD and NASH in US adults. The representativeness of 3739 US adults aged ≥20 years old who had completed 24 h dietary recall interviews and measurements, including dietary, SSBs, smoking, physical activity, and liver stiffness measurements, were selected from the National Health and Nutrition Examination Survey 2017-2020 surveys. Chi-square tests, t-tests, and weighted logistic regression models were utilized for analyses. The prevalence of NASH was 20.5%, and that of NAFLD (defined without NASH) was 32.7% of US. adults. We observed a higher prevalence of NASH/NAFLD in men, Mexican-Americans, individuals with sugar intake from SSBs, light-moderate alcohol use, lower physical activity levels, higher energy intake, obesity, and medical comorbidities. Heavy sugar consumption through SSBs was significantly associated with NAFLD (aOR = 1.60, 95% CI = 1.05-2.45). In addition, the intake of ASBs only (compared to the non-SSB category) was significantly associated with NAFLD (aOR = 1.78, 95% CI = 1.04-3.05), after adjusting for demographic, risk behaviors, and body mass index. A higher sugar intake from SSBs and exclusive ASB intake are both associated with the risk of NAFLD.

Dietary Patterns, Foods, and Nutrients to Ameliorate Non-Alcoholic Fatty Liver Disease: A Scoping Review

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease without pharmacological treatment yet. There is also a lack of specific dietary recommendations and strategies to treat the negative health impacts derived from NAFLD.

OBJECTIVE

This scoping review aimed to compile dietary patterns, foods, and nutrients to ameliorate NAFLD.

METHODS

A literature search was performed through MEDLINE, Scopus, Web of Science, and Google Scholar.

RESULTS

Several guidelines are available through the literature. Hypocaloric Mediterranean diet is the most accepted dietary pattern to tackle NAFLD. Coffee consumption (sugar free) may have a protective effect for NAFLD. Microbiota also plays a role in NAFLD; hence, fibre intake should be guaranteed.

CONCLUSIONS

A high-quality diet could improve liver steatosis. Weight loss through hypocaloric diet together with physical activity and limited sugar intake are good strategies for managing NAFLD. Specific dietary recommendations and a Mediterranean plate have been proposed to ameliorate NAFLD.

Protective effects of caffeine against palmitate-induced lipid toxicity in primary rat hepatocytes is associated with modulation of adenosine receptor A1 signaling

BACKGROUND

Epidemiological evidence has shown an association between coffee consumption and reduced risk for chronic liver diseases, including metabolic-dysfunction-associated liver disease (MALFD). Lipotoxicity is a key cause of hepatocyte injury during MAFLD. The coffee component caffeine is known to modulate adenosine receptor signaling via the antagonism of adenosine receptors. The involvement of these receptors in the prevention of hepatic lipotoxicity has not yet been explored. The aim of this study was to explore whether caffeine protects against palmitate-induced lipotoxicity by modulating adenosine receptor signaling.

METHODS

Primary hepatocytes were isolated from male rats. Hepatocytes were treated with palmitate with or without caffeine or 1,7DMX. Lipotoxicity was verified using Sytox viability staining and mitochondrial JC-10 staining. PKA activation was verified by Western blotting. Selective (ant)agonists of A1AR (DPCPX and CPA, respectively) and A2AR (istradefyline and regadenoson, respectively), the AMPK inhibitor compound C, and the Protein Kinase A (PKA) inhibitor Rp8CTP were used. Lipid accumulation was verified by ORO and BODIPY 453/50 staining.

RESULTS

Caffeine and its metabolite 1,7DMX prevented palmitate-induced toxicity in hepatocytes. The A1AR antagonist DPCPX also prevented lipotoxicity, whereas both the inhibition of PKA and the A1AR agonist CPA (partially) abolished the protective effect. Caffeine and DPCPX increased lipid droplet formation only in palmitate-treated hepatocytes and decreased mitochondrial ROS production.

CONCLUSIONS

The protective effect of caffeine against palmitate lipotoxicity was shown to be dependent on A1AR receptor and PKA activation. Antagonism of A1AR also protects against lipotoxicity. Targeting A1AR receptor may be a potential therapeutic intervention with which to treat MAFLD.

Nutritional and Lifestyle Therapy for NAFLD in People with HIV

HIV infection and nonalcoholic fatty liver disease (NAFLD) are two major epidemics affecting millions of people worldwide. As people with HIV (PWH) age, there is an increased prevalence of metabolic comorbidities, along with unique HIV factors, such as HIV chronic inflammation and life-long exposure to antiretroviral therapy, which leads to a high prevalence of NAFLD. An unhealthy lifestyle, with a high dietary intake of refined carbohydrates, saturated fatty acids, fructose added beverages, and processed red meat, as well as physical inactivity, are known to trigger and promote the progression of NAFLD to nonalcoholic steatohepatitis, liver fibrosis, and hepatocellular carcinoma. Furthermore, with no currently approved pharmacotherapy and a lack of clinical trials that are inclusive of HIV, nutritional and lifestyle approaches still represent the most recommended treatments for PWH with NAFLD. While sharing common features with the general population, NAFLD in PWH displays its own peculiarities that may also reflect different impacts of nutrition and exercise on its onset and treatment. Therefore, in this narrative review, we aimed to explore the role of nutrients in the development of NAFLD in PWH. In addition, we discussed the nutritional and lifestyle approaches to managing NAFLD in the setting of HIV, with insights into the role of gut microbiota and lean NAFLD.

Nutritional intervention in the management of non-alcoholic fatty liver disease

Lifestyle modification is the primary intervention to control NAFLD progression, but despite evidence-based effectiveness it is difficult to distinguish the benefits of nutrition from physical activity and the optimal diet composition is not established. Macronutrients as saturated fatty acids, sugars and animal proteins are harmful in NAFLD and the Mediterranean Diet reducing sugar, red meat and refined carbohydrates and increasing unsaturated-fatty-acids was reported to be beneficial. However one size cannot fit all since NAFLD is a multifaceted syndrome encompassing many diseases of unknown etiologies, different clinical severity and outcomes. Studies of the intestinal metagenome, provided new insights into the physio-pathological interplay between intestinal microbiota and NAFLD. How much the microbiota heterogeneity can influence response to diet remains unknown. New knowledge indicates that AI guided personalized nutrition based on clinic-pathologic and genetic data combined with pre/post nutritional intervention gut metagenomics/metabolomics will be part of the future management of NAFLD.

Understanding NAFLD: From Case Identification to Interventions, Outcomes, and Future Perspectives

While non-alcoholic fatty liver disease (NAFLD) is a prevalent and frequent cause of liver-related morbidity and mortality, it is also strongly associated with cardiovascular disease-related morbidity and mortality, likely driven by its associations with insulin resistance and other manifestations of metabolic dysregulation. However, few satisfactory pharmacological treatments are available for NAFLD due in part to its complex pathophysiology, and challenges remain in stratifying individual patient's risk for liver and cardiovascular disease related outcomes. In this review, we describe the development and progression of NAFLD, including its pathophysiology and outcomes. We also describe different tools for identifying patients with NAFLD who are most at risk of liver-related and cardiovascular-related complications, as well as current and emerging treatment options, and future directions for research.

Caffeine in liver diseases: Pharmacology and toxicology

We have previously shown that adenosine A1AR antagonists, adenosine A2aAR antagonists, and caffeine have significant inhibitory effects on the activation and proliferation of hepatic stellate cells in alcoholic liver fibrosis. Many recent studies have found that moderate coffee consumption is beneficial for various liver diseases. The main active ingredient of coffee is caffeine, which is a natural non-selective adenosine receptor antagonist. Moreover, numerous preclinical epidemiological studies and clinical trials have examined the association between frequent coffee consumption and the risk of developing different liver diseases. In this review, we summarize and analyze the prophylactic and therapeutic effects of caffeine on various liver diseases, with an emphasis on cellular assays, animal experiments, and clinical trials. To review the prevention and treatment effects of caffeine on different liver diseases, we searched all literature before 19 July 2022, using “caffeine” and “liver disease” as keywords from the PubMed and ScienceDirect databases. We found that moderate coffee consumption has beneficial effects on various liver diseases, possibly by inhibiting adenosine binding to its receptors. Caffeine is a potential drug for the prevention and treatment of various liver diseases.

The role of dietary factors in nonalcoholic fatty liver disease to hepatocellular carcinoma progression: A systematic review

BACKGROUND AND AIMS

Dietary factors play an important role in promoting nonalcoholic fatty liver disease (NAFLD)-related hepatocellular carcinoma (HCC) development through regulation of metabolism and inflammation. However, so far there was no evidence regarding how dietary factors may influence different disease outcomes in the NAFLD to HCC progression. Our study aimed to comprehensively evaluate the role of dietary factors on the risk of progression from NAFLD to HCC.

METHODS

A comprehensive literature research was conducted in PubMed, Web of Science and Embase databases to identify case-control and cohort studies published up to March 15, 2022 in English. We included studies investigating associations of food and beverage items (excluding alcohol), food groups, dietary patterns, and dietary habits with incidence risk of four main chronic liver diseases involved in the NAFLD-to-HCC progression (i.e., NAFLD, liver fibrosis, liver cirrhosis, and HCC). Three researchers independently performed the literature search, selected eligible articles, performed data abstraction and evaluated study quality. After evaluating adequacy and credibility of the associations reported for each dietary factor and each liver disease outcome, we summarized and evaluated the consistency of associations based on a priori determined criteria considering study design and the proportion of significant associations.

RESULTS

There were 109 studies included in this review (47 on NAFLD, 1 on liver fibrosis, 6 on liver cirrhosis, and 55 on HCC). Consistent evidence suggested that higher dietary inflammatory potential was associated with increased risk of both NAFLD and HCC whereas Mediterranean diet was associated with lower risk of both diseases. Additionally, greater conformity to the Healthy Eating Index, Dietary Approaches to Stop Hypertension score, and Mediterranean Diet Score, and dietary patterns with high dietary antioxidant capacity reduced NAFLD risk. Some specific foods including soft drinks and red and/or processed meat were associated with increased NAFLD risk while total vegetables and spinach were associated with reduced NAFLD risk. Coffee and white meat consumption were inversely related to HCC risk.

CONCLUSIONS

Dietary patterns or individual foods representing a more anti-inflammatory potential were associated with reduced risk of both NAFLD and HCC, which implied diet-induced inflammation may impact NAFLD progression towards HCC.

Effects of Coffee on the Gastro-Intestinal Tract: A Narrative Review and Literature Update

The objective of the present research was to review the state of the art on the consequences of drinking coffee at the different levels of the gastrointestinal tract. At some steps of the digestive process, the effects of coffee consumption seem rather clear. This is the case for the stimulation of gastric acid secretion, the stimulation of biliary and pancreatic secretion, the reduction of gallstone risk, the stimulation of colic motility, and changes in the composition of gut microbiota. Other aspects are still controversial, such as the possibility for coffee to affect gastro-esophageal reflux, peptic ulcers, and intestinal inflammatory diseases. This review also includes a brief summary on the lack of association between coffee consumption and cancer of the different digestive organs, and points to the powerful protective effect of coffee against the risk of hepatocellular carcinoma. This review reports the available evidence on different topics and identifies the areas that would most benefit from additional studies.

Chlorogenic acid improves glucose tolerance, lipid metabolism, inflammation and microbiota composition in diabetic db/db mice

INTRODUCTION

Chronic and acute chlorogenic acid (CGA) can improve glucose tolerance (GT) and insulin sensitivity (IS). However, whether acute administration of CGA has beneficial effects on hepatic lipid metabolism and cecal microbiota composition remains unclear.

METHODS

In the current study, diabetic db/db mice were administered CGA or metformin, and db/m mice were used as controls to explore the effects of CGA on hepatic lipid metabolism, including fatty acid oxidation and transportation and triglyceride (TG) lipolysis and synthesis. Moreover, alterations in the inflammatory response and oxidative stress in the liver and gut microbe composition were evaluated.

RESULTS

The results showed that CGA decreased body weight and improved glucose tolerance and insulin resistance, and these effects were similar to those of metformin. CGA decreased hepatic lipid content by increasing the expression of CPT1a (carnitine palmitoyltransferase 1a), ACOX1 (Acyl-CoA oxidase 1), ATGL (adipose triglyceride lipase), and HSL (hormone-sensitive lipase) and decreasing that of MGAT1 (monoacylglycerol O-acyltransferase 1), DGAT1 (diacylglycerol O-acyltransferase), DGAT2, CD36, and FATP4 (fatty acid transport protein 4). Additionally, CGA restored the expression of inflammatory genes, including TNF-α (tumor necrosis factor-alpha), IL-1β (interleukin-1beta), IL-6, and IL-10, and genes encoding antioxidant enzymes, including SOD1 (superoxide dismutases 1), SOD2 (superoxide dismutases 2), and GPX1 (glutathione peroxidase 1). Furthermore, CGA improved the bacterial alpha and beta diversity in the cecum. Moreover, CGA recovered the abundance of the phylum Bacteroidetes and the genera Lactobacillus, Blautia, and Enterococcus.

DISCUSSION

CGA can improve the antidiabetic effects, and microbes may critically mediate these beneficial effects.

Effect of Coffee Consumption on Non-Alcoholic Fatty Liver Disease Incidence, Prevalence and Risk of Significant Liver Fibrosis: Systematic Review with Meta-Analysis of Observational Studies

Background and aim: Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide. Given the anti-fibrotic and antioxidant properties of coffee, this systematic review and meta-analysis aims to provide updated results on the impact of coffee consumption on NAFLD incidence, prevalence, and risk of significant liver fibrosis. Methods: We conducted a comprehensive search in MEDLINE (OvidSP) and Scopus from January 2010 through January 2021. Relative risks for the highest versus the lowest level of coffee consumption were pooled using random-effects models. Heterogeneity and publication bias were evaluated using the Higgins’ I² statistic and Egger’s regression test, respectively. Results: Eleven articles consisting of two case-control studies, eight cross-sectional studies, and one prospective cohort study were included in the meta-analysis. Of those, three studies with 92,075 subjects were included in the analysis for NAFLD incidence, eight studies with 9558 subjects for NAFLD prevalence, and five with 4303 subjects were used for the analysis of liver fibrosis. There was no association between coffee consumption and NAFLD incidence (RR 0.88, 95% CI 0.63–1.25, p = 0.48) or NAFLD prevalence (RR 0.88, 95% CI 0.76–1.02, p = 0.09). The meta-analysis showed coffee consumption to be significantly associated with a 35% decreased odds of significant liver fibrosis (RR 0.65, 95% CI 0.54–0.78, p < 0.00001). There was no heterogeneity (I² = 11%, p = 0.34) and no evidence of publication bias (p = 0.134). Conclusion: This meta-analysis supports the protective role of coffee consumption on significant liver fibrosis in patients with NAFLD. However, the threshold of coffee consumption to achieve hepatoprotective effects needs to be established in prospective trials.