Mediterranean Diet and NAFLD: What We Know and Questions That Still Need to Be Answered

Vegetarian diets and risk of nonalcoholic fatty liver disease: An observational study of National Health and Nutrition Examination Survey 2005-2018 using propensity score methods

BACKGROUND

Studies on the association between vegetarian diets and nonalcoholic fatty liver disease (NAFLD) are limited and have inconsistent results. This study aims to explore the association between vegetarian diets and NAFLD and compare the stage of fibrosis between vegetarians and nonvegetarians in a US representative sample.

METHODS

Cross-sectional data from 23,130 participants aged ≥20 years were obtained from the National Health and Nutrition Examination Survey, 2005-2018. Vegetarian status was classified based on two 24-h dietary recalls. We examined the association between vegetarian diets and the risk of NAFLD using the propensity score weighting method.

RESULTS

Vegetarian diets were significantly associated with decreases in hepatic steatosis index (HSI), US fatty liver index and nonalcoholic fatty liver disease fibrosis score with mean differences of -2.70 (95% confidence interval [CI]: -3.69, -1.70), -3.03 (95% CI: -7.15, -0.91) and -0.12 (95% CI: -0.26, -0.01), respectively. While modelling the risk of NAFLD, we estimated that vegetarians were 53% less likely to have NAFLD assessed by HSI (odds ratios [OR]: 0.47; 95% CI: 0.34, 0.65). The effect of vegetarian diets was higher among individuals with lower waist circumferences (OR: 0.20) than among those with higher waist circumferences (OR: 0.53,p interaction ${p}_{\text{interaction}}\,$ = 0.004). However, the association was largely attenuated after adjusting for body mass index and diabetes status. No significant association was identified between vegetarian diets and advanced fibrosis.

CONCLUSIONS

Vegetarian diets were associated with a lower prevalence of NAFLD among US adults, and the association appeared to be stronger in people with lower waist circumferences. Further studies are warranted to replicate our findings.

Standard and New Echocardio Techniques, Such as Global Longitudinal Strain, to Monitor the Impact of Diets on Cardiovascular Diseases and Heart Function

"The Seven Countries Study", published in 1984, was the first study to find a correlation between diet and mortality related to cardiovascular diseases (CVDs). Since then, many investigations have addressed the relationship between type of diet, or specific nutrients, and CVDs. Based on these findings, some traditional dietary models, such as the Mediterranean or Nordic diet, are recommended to prevent CVDs. Meanwhile, new diets have been proposed for optimal nutrition therapy, for example, the Dietary Approaches to Stop Hypertension (DASH) and the Mediterranean-DASH Intervention Diet for Neurodegenerative Delay (MIND). The main outcomes evaluated after implementing these dietary models are as follows: CVD-related death; the development of specific CVDs, such as myocardial infarction and hypertension; or biochemical parameters related to CVDs, i.e., non-HDL cholesterol, C-reactive protein (CPR) and homocysteine. However, the early impact of diet on heart functionality is less evaluated. Recently, the echographic measurement of left ventricle (LV) deformation by global longitudinal strain (GLS) has been introduced as a novel marker of clinical and subclinical cardiac dysfunction. This technology allows a subclinical evaluation of heart functionality since, differently from the traditional evaluation of left ventricle ejection fraction (LVEF), it is capable of detecting early myocardial dysfunction. In this review, we analyzed the available studies that correlate dietetic regimens to cardiovascular diseases, focusing on the relevance of LV strain to detect subclinical myocardial alteration related to diet. Evidence is presented that DASH and MIND can have a positive impact on heart functionality and that myocardial strain is useful for early detection of diet-related changes in cardiac function.

The Relationship between Pathogenesis and Possible Treatments for the MASLD-Cirrhosis Spectrum

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a term that entails a broad spectrum of conditions that vary in severity. Its development is influenced by multiple factors such as environment, microbiome, comorbidities, and genetic factors. MASLD is closely related to metabolic syndrome as it is caused by an alteration in the metabolism of fatty acids due to the accumulation of lipids because of an imbalance between its absorption and elimination in the liver. Its progression to fibrosis is due to a constant flow of fatty acids through the mitochondria and the inability of the liver to slow down this metabolic load, which generates oxidative stress and lipid peroxidation, triggering cell death. The development and progression of MASLD are closely related to unhealthy lifestyle habits, and nutritional epigenetic and genetic mechanisms have also been implicated. Currently, lifestyle modification is the first-line treatment for MASLD and nonalcoholic steatohepatitis; weight loss of ≥10% produces resolution of steatohepatitis and fibrosis regression. In many patients, body weight reduction cannot be achieved; therefore, pharmacological treatment should be offered in particular populations.

The Interplay between Endocrine-Disrupting Chemicals and the Epigenome towards Metabolic Dysfunction-Associated Steatotic Liver Disease: A Comprehensive Review

Metabolic dysfunction-associated steatotic liver disease (MASLD), described as the most prominent cause of chronic liver disease worldwide, has emerged as a significant public health issue, posing a considerable challenge for most countries. Endocrine-disrupting chemicals (EDCs), commonly found in daily use items and foods, are able to interfere with nuclear receptors (NRs) and disturb hormonal signaling and mitochondrial function, leading, among other metabolic disorders, to MASLD. EDCs have also been proposed to cause transgenerationally inherited alterations leading to increased disease susceptibility. In this review, we are focusing on the most prominent linking pathways between EDCs and MASLD, their role in the induction of epigenetic transgenerational inheritance of the disease as well as up-to-date practices aimed at reducing their impact.

Exploring the Multifaceted Landscape of MASLD: A Comprehensive Synthesis of Recent Studies, from Pathophysiology to Organoids and Beyond

Non-alcoholic fatty liver disease (NAFLD) is a widespread contributor to chronic liver disease globally. A recent consensus on renaming liver disease was established, and metabolic dysfunction-associated steatotic liver disease, MASLD, was chosen as the replacement for NAFLD. The disease's range extends from the less severe MASLD, previously known as non-alcoholic fatty liver (NAFL), to the more intense metabolic dysfunction-associated steatohepatitis (MASH), previously known as non-alcoholic steatohepatitis (NASH), characterized by inflammation and apoptosis. This research project endeavors to comprehensively synthesize the most recent studies on MASLD, encompassing a wide spectrum of topics such as pathophysiology, risk factors, dietary influences, lifestyle management, genetics, epigenetics, therapeutic approaches, and the prospective trajectory of MASLD, particularly exploring its connection with organoids.

Frontiers and hotspots of adipose tissue and NAFLD: a bibliometric analysis from 2002 to 2022

Background: The annual incidence of non-alcoholic fatty liver disease (NAFLD) continues to rise steadily. In recent years, adipose tissue (AT) has gained recognition as a pivotal contributor to the pathogenesis of NAFLD. Employing bibliometric analysis, we examined literature concerning AT and NAFLD. Methods: Relevant literature on AT in NAFLD from 1980 to 2022 was extracted from the Web of Science Core Collection. These records were visualized using CiteSpace and VOSviewer regarding publications, countries/regions, institutions, authors, journals, references, and keywords. Results: Since 2002, a total of 3,330 papers have been included, exhibiting an annual surge in publications. Notably, the quality of publications is superior in the USA and Europe. Kenneth Cusi stands out as the author with the highest number of publications and H-index. Hepatology is the journal boasting the highest citation and H-index. The University of California System holds the highest centrality among institutions. References specifically delve into physiological processes associated with AT in NAFLD. Currently, lipid metabolism and inflammation constitute the principal research mechanisms in the AT-based regulation of NAFLD, with pertinent keywords including microRNA, T cell, hypoxia, sarcopenia, hepatokine, gut microbiota, and autophagy. The Mediterranean diet is among the most widely recommended dietary approaches for potential NAFLD treatment. Conclusion: This paper represents the inaugural bibliometric study on the effects of AT on NAFLD, offering valuable insights and directions for future research.

Diets with Higher Anti-inflammatory Potential Associated with Lower Risk of Development of Nonalcoholic Fatty Liver Disease and Early-Stage of Fibrosis Among US Adults

BACKGROUND

There is limited evidence of how dietary inflammatory potential influences nonalcoholic fatty liver disease (NAFLD) progression.

AIMS

Our study aims to evaluate the association of dietary inflammatory index (DII) with liver fibrosis, a hallmark feature of NAFLD, among US adults.

METHODS

Cross-sectional data consisting of 5,506 participants in the National Health and Nutrition Examination Survey from 2011 to 2018 were used. Energy adjusted-DII (E-DII) scores were calculated using 2 days of 24-h dietary recall data. We used a partial proportional odds model to determine risk at each stage of fibrosis according to the E-DII score.

RESULTS

The weighted prevalence of NAFLD (assessed by US fatty liver index) was 34.5%, with 23.2% (assessed by NAFLD Fibrosis Score) having mild fibrosis, 10.4% intermediate fibrosis, and 0.9% advanced fibrosis. When comparing the most pro-inflammatory diets to the most anti-inflammatory diets (AIDs) in the multivariable model, the marginal probability effect (MPE) of NAFLD, mild fibrosis and intermediate fibrosis increased by 11.7% (95% CI 6.6%, 16.9%), 7.0% (95% CI 3.5%, 10.4%) and 4.0% (95% CI 0.3%, 7.5%), respectively. The MPE of advanced fibrosis was not significant (MPE = 0.7%; 95% CI - 1.1%, 2.8%). Similar associations were observed when applying Fibrosis-4 and transient elastography as fibrosis diagnostic measurements.

CONCLUSIONS

An AID was associated with lower risk of development of NAFLD and early-stage of fibrosis among US adults. But the associations became attenuated and dissipated as the fibrogenesis became severe. Further studies are needed to re-confirm our observations.

Liver fat as risk factor of hepatic and cardiometabolic diseases

Non-alcoholic fatty liver disease (NAFLD) is a disorder characterized by excessive accumulation of fat in the liver that can progress to liver inflammation (non-alcoholic steatohepatitis [NASH]), liver fibrosis, and cirrhosis. Although most efforts for drug development are focusing on the treatment of the latest stages of NAFLD, where significant fibrosis and NASH are present, findings from studies suggest that the amount of liver fat may be an important independent risk factor and/or predictor of development and progression of NAFLD and metabolic diseases. In this review, we first describe the current tools available for quantification of liver fat in humans and then present the clinical and pathophysiological evidence that link liver fat with NAFLD progression as well as with cardiometabolic diseases. Finally, we discuss current pharmacological and non-pharmacological approaches to reduce liver fat and present open questions that have to be addressed in future studies.

Lactobacillus oris improves non-alcoholic fatty liver in mice and inhibits endogenous cholesterol biosynthesis

We previously confirmed that a strain of Lactobacillus oris isolated from the fecal samples of healthy Hainan centenarian having potent lipid-lowering ability in HepG2 cells; and this study was to investigate the effect of the stain on non-alcoholic fatty liver in mice in vivio. The Lactobacillus oris strain isolated from Hainan centenarian fecal samples were frozen stored in our laboratory. Thirty ob/ob mice (10 in each group) were orally gavaged with Lactobacillus oris (Lactobacillus, 5 × 109 cfu), mixed probiotics (Mixed, 5 × 109 cfu, a mixture with known lipid-lowering ability), or culture medium (Control) respectively. Lactobacillus oris isolated from fecal samples of Hainan centenarians showed significantly in vivo lipid lowering ability compared with the controls, and the ability was comparable with mixed probiotics strains in mice The possible mechanisms of lipid-lowering of probiotics and Lactobacillus oris may be associated with HMGR inhibition to suppress the synthesis of endogenous cholesterol; bile acids reabsorption, and intestinal FXR-FGF15 signaling pathways promoting the cholesterol conversion into bile acids secretion.

Effect of bariatric surgery on NAFLD/NASH: a single-centre observational prospective cohort study

INTRODUCTION

The prevalence of non-alcoholic fatty liver disease (NAFLD) ranges from 25% in the general population to 90% in patients with obesity scheduled for bariatric surgery. NAFLD can progress towards non-alcoholic steatohepatitis (NASH) associated with complications such as cirrhosis, hepatocellular carcinoma and cardiovascular disease. To date, losing weight and lifestyle modifications are the best known treatments for NASH. Bariatric surgery significantly improves NAFLD/NASH in the short term. However, the extent of this improvement is not yet clear and long-term data on the natural course of NAFLD/NASH after bariatric surgery are lacking. The factors involved in NAFLD/NASH regression after bariatric surgery have not been elucidated.

METHODS AND ANALYSIS

This is an observational prospective cohort study including patients scheduled for bariatric surgery. Extensive metabolic and cardiovascular analyses will be carried out including measurements of carotid intima media thickness and pulse wave velocity. Genomic, proteomic, lipidomic and metabolomic studies will be done. Microbioma analyses before and 1 year after surgery will be done. Transient elastography measurements will be performed before and at 1, 3 and 5 years after surgery. For those with an elevated preoperative transient elastography measurement by Fibroscan, a laparoscopic liver biopsy will be performed during surgery. Primary outcome measures are the change of steatosis and liver fibrosis 5 years after surgery. Secondary outcome measure is the comparison of the transient elastography measurements with the NAFLD Activity Score from the biopsies.

ETHICS AND DISSEMINATION

The protocol has been approved by the Medical Research Ethics Committees United, Nieuwegein, on 1 March 2022 (registration code R21.103/NL79423.100.21). The study results will be submitted for publication in peer-reviewed journals and data will be presented at scientific meetings.

TRIAL REGISTRATION NUMBER

NCT05499949.

The Replacement of Only One Portion of Starchy Carbohydrates with Green Leafy Vegetables Regresses Mid and Advanced Stages of NAFLD: Results from a Prospective Pilot Study

The gold standard treatment for NAFLD is weight loss and lifestyle interventions, which require a diet enriched in fiber and reduced in sugars and saturated fats. Fibres may be advantageous for NAFLD patients since they reduce and slow the absorption of carbohydrates, lipids, and proteins, lowering the energy density of the meal and increasing their sense of satiety. Furthermore, the polyphenol content and other bioactive compounds of vegetables have antioxidant and anti-inflammatory properties preventing disease progression. The aim of this study is to ascertain the effects of a diet enriched by green leafy vegetables and with a moderate restriction of carbohydrate intake in patients with NAFLD over a three month period. Among the forty patients screened, twenty four patients completed the clinical trial consisting of swapping one portion of carbohydrate-rich food for one portion of green leafy vegetables, and liver and metabolic markers of NAFLD were evaluated. All patients underwent routine blood tests, anthropometric measurements, bioelectrical impedance analysis, fibroscan, and fatty liver index (FLI) evaluation before and at the end of the study. The population under study (n = 24) had a median age of 47.5 (41.5-52.5) years and included mainly women (70.8%). We found that FLI, which is used to predict fatty liver (73 (33-89) vs. 85 (54-95), p < 0.0001) and the FAST score, which is a fibroscan-derived parameter identifying patients at risk of progressive NASH (0.03 (0.02-0.09) vs. 0.05 (0.02-0.15), p = 0.007), were both improved after changes in diet. The BMI (33.3 (28.6-37.3) vs. 35.3 (31.2-39.0), p < 0.0001), WC (106.5 (95.0-112.5) vs. 110.0 (103.0-124.0), p < 0.0001), neck circumference (38.0 (35.0-41.5) vs. 39.5 (38.0-42.5), p < 0.0001), fat mass (32.3 (23.4-40.7) vs. 37.9 (27.7-43.5), p < 0.0001), and extracellular water (17.3 (15.2-20.8) vs. 18.3 (15.9-22.7), p = 0.03) were also all significantly lower after three months of diet. Metabolic parameters linked to NAFLD decreased: HbA1c (36.0 (33.5-39.0) vs. 38.0 (34.0-40.5), p = 0.01), triglycerides (72 (62-90) vs. 90 (64-132), p = 0.03), and the liver markers AST (17 (14-19) vs. 18 (15-27), p = 0.01) and γGT (16 (13-20) vs. 16 (14-27), p = 0.02). In conclusion, replacing only one portion of starchy carbohydrates with one portion of vegetables for a three month period is sufficient to regress, at least in part, both mid and advanced stages of NAFLD. This moderate adjustment of lifestyle habits is easily achievable.

A Healthy Diet is Associated with a Lower Risk of Hepatic Fibrosis

BACKGROUND

Higher diet quality is associated with a lower risk of NAFLD.

OBJECTIVES

We examined the relationship between diet quality and hepatic fibrosis.

METHODS

We analyzed cross-sectional associations between 3 a priori diet quality scores-the Dietary Approaches to Stop Hypertension (DASH) score, the Alternative Healthy Eating Index (AHEI), and a modified Mediterranean-style Diet Score (MDS)-and hepatic fat [controlled attenuation parameter (CAP)] and fibrosis [liver stiffness measurement (LSM)] measured by vibration-controlled transient elastography (VCTE) in 2532 Framingham Heart Study (FHS) participants and 3295 participants of the National Health and Nutrition Examination Survey (NHANES).

RESULTS

Higher diet quality scores were associated with lower LSM in both FHS and NHANES after adjustment for demographic and lifestyle factors. Additional adjustment for CAP or BMI attenuated the observed associations. Association strength was similar across all 3 diet quality scores. Fixed-effect meta-analysis demonstrated that, under CAP-adjusted models, the LSM decreases associated with 1-SD increase of the DASH, AHEI, and MDS scores were 2% (95% CI: 0.7%, 3.3%; P = 0.002), 2% (95% CI: 0.7%, 3.3%; P = 0.003), and 1.7% (95% CI: 0.7%, 2.6%; P = 0.001), respectively, whereas in the meta-analysis of BMI-adjusted models, LSM reductions associated with 1-SD increase of the DASH, AHEI, and MDS scores were 2.2% (95% CI: -0.1%, 2.2%; P = 0.07), 1.5% (95% CI: 0.3%, 2.7%; P = 0.02), and 0.9 (95% CI: -0.1%, 1.9%; P = 0.07), respectively.

CONCLUSIONS

We demonstrated associations of higher diet quality with favorable hepatic fat and fibrosis measures. Our data suggest that a healthy diet may reduce the likelihood of obesity and hepatic steatosis as well as the progression of steatosis to fibrosis.

Mediterranean Diet Improves Plasma Biomarkers Related to Oxidative Stress and Inflammatory Process in Patients with Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) shows liver fat depots without alcohol consumption. NAFLD does not have specific drug therapies, with a healthy lifestyle and weight loss being the main approaches to prevent and treat NAFLD. The aim was to assess the antioxidant and pro-inflammatory state in patients with NAFLD after 12-month-lifestyle intervention depending on the change in adherence to a Mediterranean diet (AMD). Antioxidant and inflammatory biomarkers were measured in 67 adults (aged 40–60 years old) diagnosed with NAFLD. Anthropometric parameters and dietary intake were measured by a validated semi-quantitative 143-item food frequency questionnaire. The nutritional intervention improved anthropometric and biochemical parameters after a 12-month follow-up. However, decreases in alanine aminotransferase (ALT) and C reactive protein (CRP) were higher in participants with high AMD, which also showed higher improvement in physical fitness (Chester step test) and intrahepatic fat contents. The intervention reduced plasma levels of malondialdehyde, myeloperoxidase, zonulin, and omentin, and increased resolvin D1 (RvD1), whereas the decrease in leptin, ectodysplasin-A (EDA), cytokeratin-18 (CK-18), interleukin-1ra (IL-1ra) and endotoxin was only significant in participants with higher AMD. The current study showed that a one-year nutritional intervention improved main NAFLD features such as body mass index, IFC, liver enzymes, and prooxidant and proinflammatory status. There was also a decrease in the concentration of plasmatic endotoxin, suggesting an improvement in intestinal permeability. These health benefits were more evident in participants that improved AMD to a greater extent. The trial was registered at ClinicalTrials.gov with registry number NCT04442620.

Research progress regarding the effect and mechanism of dietary phenolic acids for improving nonalcoholic fatty liver disease via gut microbiota

Phenolic acids (PAs), a class of small bioactive molecules widely distributed in food and mainly found as secondary plant metabolites, present significant advantages such as antioxidant activity and other health benefits. The global epidemic of nonalcoholic fatty liver disease (NAFLD) is becoming a serious public health problem. Existing studies showed that gut microbiota (GM) dysbiosis is highly associated with the occurrence and development of NAFLD. In recent years, progress has been made in the study of the relationship among PA compounds, GM, and NAFLD. PAs can regulate the composition and functions of the GM to promote human health, while GM can increase the dietary sources of PAs and improve its bioavailability. This paper discussed PAs, GM, and their interrelationship while introducing several representative dietary PA sources and examining the absorption and metabolism of PAs mediated by GM. It also summarizes the effect and mechanisms of PAs in improving and regulating NAFLD via GM and their metabolites. This helps to better evaluate the potential preventive effect of PAs on NAFLD via the regulation of GM and expands the utilization of PAs and PA-rich food resources.

Nonalcoholic fatty liver disease and non-liver comorbidities

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease characterized by excess fat accumulation in the liver. It is closely associated with metabolic syndrome, and patients with NAFLD often have comorbidities such as obesity, type 2 diabetes mellitus, and dyslipidemia. In addition to liver-related complications, NAFLD has been associated with a range of non-liver comorbidities, including cardiovascular disease, chronic kidney disease, and sleep apnea. Cardiovascular disease is the most common cause of mortality in patients with NAFLD, and patients with NAFLD have a higher risk of developing cardiovascular disease than the general population. Chronic kidney disease is also more common in patients with NAFLD, and the severity of NAFLD is associated with a higher risk of developing chronic kidney disease. Sleep apnea, a disorder characterized by breathing interruptions during sleep, is also more common in patients with NAFLD and is associated with the severity of NAFLD. The presence of non-liver comorbidities in patients with NAFLD has important implications for the management of this disease. Treatment of comorbidities such as obesity, type 2 diabetes mellitus, and dyslipidemia may improve liver-related outcomes in patients with NAFLD. Moreover, treatment of non-liver comorbidities may also improve overall health outcomes in patients with NAFLD. Therefore, clinicians should be aware of the potential for non-liver comorbidities in patients with NAFLD and should consider the management of these comorbidities as part of the overall management of this disease.

Validation and Comparison of Two Dietary Indexes for Predicting Nonalcoholic Fatty Liver Disease in US Adults

BACKGROUND

Two indexes have been used to describe dietary inflammatory potential: the experiment-based dietary total antioxidant capacity (TAC) and the literature-derived dietary inflammatory index (DII). How robustly each index represents dietary inflammatory potential and the risk of nonalcoholic fatty liver disease (NAFLD) has not yet been established.

OBJECTIVES

We investigated the relation between dietary inflammatory potential and NAFLD, and compared the abilities of the TAC and DII scores to predict NAFLD in US adults.

METHODS

Cross-sectional data from 12,410 participants aged 20-80 y in the NHANES from 2011 to 2018 were identified. TAC and DII scores were calculated using 2 d of 24-h dietary recall data. We examined the association between dietary index and risk of NAFLD using linear and logistic regression models.

RESULTS

Higher energy-adjusted TAC (E-TAC) and inversely energy-adjusted DII (IE-DII) scores (both representing more anti-inflammatory diets) were associated with lower hepatic steatosis index (HSI) and US fatty liver index (USFLI) values after adjusting for potential covariates, and the association for each SD increase in the IE-DII was stronger than the E-TAC (β estimates for HSI: -0.39 compared with -0.25; P-difference = 0.036). In modeling the risk of NAFLD, we observed that participants with IE-DII scores in the highest quartile had the lowest ORs for NAFLD as assessed by either the HSI (OR: 0.77; 95% CI: 0.62, 0.96; P-trend = 0.023) or USFLI (OR: 0.48; 95% CI: 0.35, 0.68; P-trend <0.0001). TAC scores were also associated with NAFLD as assessed by the USFLI.

CONCLUSIONS

An anti-inflammatory diet is beneficial for reducing the risk of NAFLD in US adults. The DII is a stronger predictor of hepatic measures than the TAC, and we recommend that future hepatic health studies use the DII to estimate dietary inflammatory potential.

Non-pharmacological management options for MAFLD: a practical guide

Lifestyle changes should be the main basis for any treatment for metabolic dysfunction-associated fatty liver disease (MAFLD), aiming to increase energy expenditure, reduce energy intake and improve the quality of nutrients consumed. As it is a multifactorial disease, approaches such as physical exercise, a better dietary pattern, and possible pharmacological intervention are shown to be more efficient when used simultaneously to the detriment of their applications. The main treatment for MAFLD is a lifestyle change consisting of diet, activity, exercise, and weight loss. The variables for training prescription such as type of physical exercise (aerobic or strength training), the weekly frequency, and the intensity most indicated for the treatment of MAFLD remain uncertain, that is, the recommendations must be adapted to the clinical conditions comorbidities, and preferences of each subject in a way individual. This review addresses recent management options for MAFLD including diet, nutrients, gut microbiota, and physical exercise.

We are what we eat: The role of lipids in metabolic diseases

Lipids play a fundamental role, both structurally and functionally, for the correct functioning of the organism. In the last two decades, they have evolved from molecules involved only in energy storage to compounds that play an important role as components of cell membranes and signaling molecules that regulate cell homeostasis. For this reason, their interest as compounds involved in human health has been gaining weight. Indeed, lipids derived from dietary sources and endogenous biosynthesis are relevant for the pathophysiology of numerous diseases. There exist pathological conditions that are characterized by alterations in lipid metabolism. This is particularly true for metabolic diseases, such as liver steatosis, type 2 diabetes, cancer and cardiovascular diseases. The main issue to be considered is lipid homeostasis. A precise control of fat homeostasis is required for a correct regulation of metabolic pathways and safe and efficient energy storage in adipocytes. When this fails, a deregulation occurs in the maintenance of systemic metabolism. This happens because an increased concentrations of lipids impair cellular homeostasis and disrupt tissue function, giving rise to lipotoxicity. Fat accumulation results in many alterations in the physiology of the affected organs, mainly in metabolic tissues. These alterations include the activation of oxidative and endoplasmic reticulum stress, mitochondrial dysfunction, increased inflammation, accumulation of bioactive molecules and modification of gene expression. In this chapter, we review the main metabolic diseases in which alterations in lipid homeostasis are involved and discuss their pathogenic mechanisms.

Phenotypes of non-alcoholic fatty liver disease (NAFLD) and all-cause mortality: unsupervised machine learning analysis of NHANES III

OBJECTIVES

Non-alcoholic fatty liver disease (NAFLD) is a non-communicable disease with a rising prevalence worldwide and with large burden for patients and health systems. To date, the presence of unique phenotypes in patients with NAFLD has not been studied, and their identification could inform precision medicine and public health with pragmatic implications in personalised management and care for patients with NAFLD.

DESIGN

Cross-sectional and prospective (up to 31 December 2019) analysis of National Health and Nutrition Examination Survey III (1988-1994).

PRIMARY AND SECONDARY OUTCOMES MEASURES

NAFLD diagnosis was based on liver ultrasound. The following predictors informed an unsupervised machine learning algorithm (k-means): body mass index, waist circumference, systolic blood pressure (SBP), plasma glucose, total cholesterol, triglycerides, liver enzymes alanine aminotransferase, aspartate aminotransferase and gamma glutamyl transferase. We summarised (means) and compared the predictors across clusters. We used Cox proportional hazard models to quantify the all-cause mortality risk associated with each cluster.

RESULTS

1652 patients with NAFLD (mean age 47.2 years and 51.5% women) were grouped into 3 clusters: anthro-SBP-glucose (6.36%; highest levels of anthropometrics, SBP and glucose), lipid-liver (10.35%; highest levels of lipid and liver enzymes) and average (83.29%; predictors at average levels). Compared with the average phenotype, the anthro-SBP-glucose phenotype had higher all-cause mortality risk (aHR=2.88; 95% CI: 2.26 to 3.67); the lipid-liver phenotype was not associated with higher all-cause mortality risk (aHR=1.11; 95% CI: 0.86 to 1.42).

CONCLUSIONS

There is heterogeneity in patients with NAFLD, whom can be divided into three phenotypes with different mortality risk. These phenotypes could guide specific interventions and management plans, thus advancing precision medicine and public health for patients with NAFLD.

Association between hepatic steatosis and fibrosis indices and dietary habits, physical activity, and quality of life

BACKGROUND AND STUDY AIMS

This cross-sectional study aimed to evaluate the association between hepatic steatosis and fibrosis indices and adherence to the Mediterranean diet (MD), physical activity (PA), and quality of life (QoL) in individuals unaware of the status of their liver.

PATIENTS AND METHODS

Participants were asked to complete three questionnaires validated in Greek, namely: (1) the Chronic Liver Disease Questionnaire (CLDQ) for QoL assessment; (2) the semi-quantitative Food Frequency Questionnaire (FFQ), from which the MedDietScore was calculated; and (3) the International Physical Activity Questionnaire (IPAQ) for PA evaluation. Hepatic steatosis was evaluated using the Fatty Liver Index (FLI), Hepatic Steatosis Index (HSI), and Lipid Accumulation Product (LAP). Hepatic fibrosis was evaluated using the NAFLD Fibrosis Score (NFS), Fibrosis-4 (FIB-4), and AST-to-platelet ratio index (APRI).

RESULTS

This study recruited 200 participants (90% men) aged 36 ± 6 years. Hepatic steatosis indices were not associated with MedDietScore and QoL. In terms of PA, univariable analysis showed that higher values of hepatic steatosis indices were associated with less intense activity. This association remained significant only for HSI during multivariable analysis (moderate activity vs. low activity: beta: -2.0, 95% confidence interval (CI): -3.5, -0.37, p = 0.016; and high activity vs. low activity: beta: -3.3, 95% CI: -5.03, -1.60, p < 0.001), after controlling for age, waist circumference, and the presence of metabolic syndrome. When using hepatic fibrosis indices, none of the participants had high probability of advanced hepatic fibrosis or cirrhosis (F3-F4). Consequently, we were unable to extensively evaluate the association between hepatic fibrosis indices and lifestyle characteristics or QoL.

CONCLUSION

We showed that HSI, but not other steatosis indices, remained robustly associated with PA after adjusting for potential confounders in a population unaware of the presence of fatty liver.

Race and Ethnicity in Non-Alcoholic Fatty Liver Disease (NAFLD): A Narrative Review

Non-alcoholic fatty liver disease (NAFLD) is a significant public health concern worldwide with a complex etiology attributed to behavioural, environmental, and genetic causes. The worldwide prevalence of NAFLD is estimated to be 32.4% and constantly rising. Global data, however, indicate considerable heterogeneity among studies for both NAFLD prevalence and incidence. Identifying variables that affect the estimated epidemiological measures is essential to all stakeholders, including patients, researchers, healthcare providers, and policymakers. Besides helping with the research on disease etiology, it helps to identify individuals at risk of the disease, which in turn will outline the focus of the preventive measures and help to fittingly tailor individualized treatments, targeted prevention, screening, or treatment programs. Several studies suggest differences in the prevalence and severity of NAFLD by race or ethnicity, which may be linked to differences in lifestyle, diet, metabolic comorbidity profile, and genetic background, among others. Race/ethnicity research is essential as it can provide valuable information regarding biological and genetic differences among people with similar cultural, dietary, and geographical backgrounds. In this review, we examined the existing literature on race/ethnicity differences in susceptibility to NAFLD and discussed the contributing variables to such differences, including diet and physical activity, the comorbidity profile, and genetic susceptibility. We also reviewed the limitations of race/ethnicity studies in NAFLD.

Pharmacotherapy for Non-alcoholic Fatty Liver Disease Associated with Diabetes Mellitus Type 2

Non-alcoholic fatty liver disease (NAFLD) and diabetes mellitus type 2 commonly coexist as a manifestation of metabolic syndrome. The presence of diabetes promotes the progression of simple fatty liver to non-alcoholic steatohepatitis (NASH) and cirrhosis, and the presence of NAFLD increases the risk of diabetic complications. This coexistence affects a large part of the population, imposing a great burden on health care systems worldwide. Apart from diet modification and exercise, recent advances in the pharmacotherapy of diabetes offer new prospects regarding liver steatosis and steatohepatitis improvement, enriching the existing algorithm and supporting a multifaceted approach to diabetic patients with fatty liver disease. These agents mainly include members of the families of glucagon-like peptide-1 analogues and the sodium-glucose co-transporter-2 inhibitors. In addition, agents acting on more than one receptor simultaneously are presently under study, in an attempt to further enhance our available options.

Screening for Liver Steatosis and Fibrosis in Patients with Inflammatory Bowel Disease Using Vibration Controlled Transient Elastography with Controlled Attenuation Parameter

BACKGROUND AND AIMS

Inflammatory bowel diseases (IBD) are frequently associated with extraintestinal manifestations, hepatic injury being of concern in these patients. Current literature reports an increased prevalence of liver steatosis and fibrosis in subjects with IBD and the pathophysiology is yet to be completely understood. The aim of this study was to assess the prevalence of non-alcoholic fatty liver disease (NAFLD) in patients with IBD, as well as to determine the factors that connect these two disorders.

METHODS

From September 2021 to June 2022, 82 consecutive IBD patients were enrolled from a tertiary care center hospital in Iasi. Vibration-Controlled Transient Elastography with Controlled Attenuation Parameter (CAP) was used to assess the presence of NAFLD, with a cut-off score for CAP of 248 dB/m. Significant liver fibrosis was considered at a cut-off for liver stiffness measurements (LSM) of 7.2 kPa.

RESULTS

In total, 82 IBD patients (54.8% men, mean age of 49 ± 13 years) were included, 38 (46.3%) of them being diagnosed with NAFLD, with a mean CAP score of 286 ± 35.4 vs. 203 ± 29.7 in patients with IBD only. Age (β = 0.357, p = 0.021), body mass index (BMI) (β = 0.185, p = 0.048), disease duration (β = 0.297, p = 0.041), C-reactive protein (β = 0.321, p = 0.013), fasting plasma glucose (β = 0.269, p = 0.038), and triglycerides (β = 0.273, p = 0.023) were strongly associated with the presence of liver steatosis. The multivariate analysis showed that older age, BMI, and disease duration were strongly associated with significant liver fibrosis in our group.

CONCLUSIONS

NAFLD is a multifaced pathology with growing prevalence among IBD patients. Additional studies are needed to completely understand this problem and to create a solid evidence-based framework for more effective preventative and intervention strategies.

Impact on Prevalence of the Application of NAFLD/MAFLD Criteria in Overweight and Normal Weight Patients

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is considered the hepatic manifestation of metabolic syndrome. Recently, the term metabolic dysfunction-associated fatty liver disease (MAFLD) has been proposed and adapted to body mass index (BMI). This study describes the impact on prevalence of the application of both criteria in overweight and lean patients.

METHODS

Patients who were evaluated for liver steatosis by transient elastography were included and divided according to BMI (≥25 kg/m² and <25 kg/m²) and classified as NAFLD or MAFLD, according to metabolic abnormalities. Differences in prevalence were evaluated applying both criteria. A multivariate analysis was performed to evaluate independent associations of metabolic abnormalities and liver steatosis in lean patients.

RESULTS

3847 patients were included. In overweight patients (61%), the prevalence NAFLD was 63.6% and 65.3% for MAFLD (p = 0.22). In contrast, the prevalence of MAFLD was lower (7.9% vs. 18.3%, p ≤ 0.001) in lean patients. In this group, higher age, fasting glucose, triglycerides, and waist circumference showed independent association with liver steatosis.

CONCLUSION

The application of NAFLD/MAFLD criteria did not show prevalence differences in overweight patients. With MAFLD criteria, the prevalence is lower in lean patients, but patients with high risk of progression of liver disease for steatosis were identified, according to their metabolic abnormalities.

Dietary Acid Load (DAL), Glycated Hemoglobin A1c (HbA1c), and Metabolic Syndrome (MeS) Mediate the Association of the Adherence to the Dietary Approaches to Stopping Hypertension (DASH) and Mediterranean Diet (MeD) With Nonalcoholic Fatty Liver Disease

The study aimed to investigate the association of adults adhering to Dietary Approaches to Stop Hypertension (DASH) and Mediterranean diet (MeD) with nonalcoholic fatty liver disease (NAFLD) using structural equation modeling (SEM) in Iran. In this population-based cross-sectional study, 3,220 adults (44.65% female) aged ≥18 years were selected from the Amol Cohort Study (AmolCS). The dietary intakes were assessed by a validated 168-item semi-quantitative food-frequency questionnaire (FFQ). Residual method energy adjustment of MeD and DASH scores were calculated. Demographic characteristics and anthropometric and laboratory measurements were collected. NAFLD was diagnosed by an expert radiologist via ultrasound sonography. Based on the primary hypothesis, DASH, MeD, and NAFLD were fitted into models. Metabolic syndrome (MeS) as a potential risk factor directly affected NAFLD risk in all these models. In both genders, the higher adherence to DASH negatively affected NAFLD risk indirectly through the two following paths. (1) Dietary acid load (DAL) and metabolic syndrome (2) DAL and hemoglobin A1c (HbA1c). In addition, the higher DAL positively affected NAFLD risk among male participants indirectly via increasing HbA1c level and MeS (from DAL to HbA1c: β = 0.07, P < 0.001; from HbA1c to MeS: β = 0.10, P < 0.001). Similarly, in both genders, the relationship between MeD and NAFLD was mediated through (1) DAL, HbA1c, and MeS and (2) DAL and MeS. Further, among male participants, the MeD and NAFLD risk were also associated via the mediators of HbA1c and MeS. In female participants, the higher MeD score was directly associated with a reduction of NAFLD risk (β = -0.07, P = 0.008). The present study found three important mediators, including DAL, HbA1c, and MeS, in the association of DASH and MeD scores with NAFLD risk. Preventive and therapeutic interventions should target the mediators, including DAL, HbA1c, MeS, and its components, to reduce NAFLD incidence in the general population.

Mitochondrial Dysfunction Plays Central Role in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a global pandemic that affects one-quarter of the world’s population. NAFLD includes a spectrum of progressive liver disease from steatosis to nonalcoholic steatohepatitis (NASH), fibrosis, and cirrhosis and can be complicated by hepatocellular carcinoma. It is strongly associated with metabolic syndromes, obesity, and type 2 diabetes, and it has been shown that metabolic dysregulation is central to its pathogenesis. Recently, it has been suggested that metabolic- (dysfunction) associated fatty liver disease (MAFLD) is a more appropriate term to describe the disease than NAFLD, which puts increased emphasis on the important role of metabolic dysfunction in its pathogenesis. There is strong evidence that mitochondrial dysfunction plays a significant role in the development and progression of NAFLD. Impaired mitochondrial fatty acid oxidation and, more recently, a reduction in mitochondrial quality, have been suggested to play a major role in NAFLD development and progression. In this review, we provide an overview of our current understanding of NAFLD and highlight how mitochondrial dysfunction contributes to its pathogenesis in both animal models and human subjects. Further we discuss evidence that the modification of mitochondrial function modulates NAFLD and that targeting mitochondria is a promising new avenue for drug development to treat NAFLD/NASH.

Dietary patterns in non-alcoholic fatty liver disease (NAFLD): Stay on the straight and narrow path!

Non-alcoholic fatty liver disease (NAFLD) is the most frequent hepatic disease globally. NAFLD patients are at an increased risk of both liver and cardiovascular morbidity and mortality, as well as all-cause death. NAFLD prevalence is rapidly increasing worldwide and, thus, there is an urgent need for health policies to tackle its development and complications. Currently, since there is no drug therapy officially indicated for this disease, lifestyle interventions remain the first-line therapeutic option. In the present narrative review, we discuss the effects of certain dietary patterns on NAFLD incidence and progression. The Mediterranean diet is regarded as the diet of choice for the prevention/treatment of NAFLD and its complications, based on the available evidence. Other plant-based dietary patterns (poor in saturated fat, refined carbohydrates, red and processed meats) are also beneficial [i.e., Dietary Approaches to Stop Hypertension (DASH) and vegetarian/vegan diets], whereas more data are needed to establish the role of ketogenic, intermittent fasting and paleo diets in NAFLD. Nevertheless, there is no "one-size-fits-all" dietary intervention for NAFLD management. Clinicians should discuss with their patients and define the diet that each individual prefers and is able to implement in his/her daily life.

Prevalence of nonalcoholic fatty liver disease using noninvasive techniques among children, adolescents, and youths living with HIV

OBJECTIVE

The prevalence of subclinical liver abnormalities is high among people with HIV, but data regarding perinatally HIV-infected children and adolescents (PHIV) are scarce. Noninvasive image techniques offer an opportunity to address nonalcoholic fatty liver disease (NAFLD) in a population in which the scores validated for adults have not been tested.

DESIGN

Prospective cross-sectional study including PHIV and uninfected controls.

METHODS

Noninvasive imaging techniques for the diagnosis of NAFLD and/or fibrosis were performed, and four scores to predict NAFLD were evaluated.

RESULTS

Seventy-six participants (59.2% women) with a median of 19 years old (interquartile range: 15.5-25.6) were included, 38 were PHIV and 38 were age and sex-matched controls. All HIV participants were on ART at the moment of inclusion, and 86.8% were virologically suppressed. A total of 11 PHIV and three controls were diagnosed with NAFLD (28.9% vs. 7.9%; P = 0.02) by noninvasive imaging techniques. The performance of scores based on clinical and analytical parameters was very poor. Although nonsignificant, overweight was more common among participants with NAFLD, who had a significantly higher BMI. Differences in HIV-related parameters between the groups were nonsignificant, except for the CD4+/CD8+ T-cells ratio, decreased among PHIV diagnosed with NAFLD (P = 0.04).

CONCLUSIONS

The prevalence of NAFLD was high (28.9%) among PHIV, and only partially explained by overweight and metabolic syndrome defining factors. The scores based on clinical and analytical parameters did not accurately identify participants at risk. Therefore, liver ultrasound assessment should be considered for the screening of NAFLD among PHIV in routine clinical practice.

Is there an 'ideal' diet for patients with NAFLD?

Nonalcoholic fatty liver disease (NAFLD) is a growing epidemic that encompasses three distinct clinical phenotypes: uncomplicated fatty liver, nonalcoholic steatohepatitis (NASH) and NASH-related cirrhosis with its complications, including hepatocellular carcinoma. To date, no pharmacological treatments have been approved and lifestyle modifications including reduced caloric intake targeting a 7%-10% weight loss from baseline assessment represent the standard approach. Mediterranean diet has been recommended as the best dietary pattern since it is easy to follow and, independently of caloric intake its nutritional components have beneficial metabolic effects that not only improve steatosis but also risk factors for cardiovascular events, the leading cause of morbidity/mortality in individuals with NAFLD. Other dietary patterns such as ketogenic diet and Dietary Approach to Stop Hypertension (DASH) diet can be used in patients with NAFLD. Recently, intermittent fasting diets have gained popularity among healthy individuals and have been proposed as a safe and effective treatment for the metabolic syndrome in experimental and in a few human studies. In this narrative review, we aim to summarize the evidence for the available dietary approaches for patients with NAFLD.

Nonalcoholic fatty liver disease: lifestyle and quality of life

Nonalcoholic fatty liver disease (NAFLD) is a metabolic disorder whose current rapidly expanding prevalence is causing it to develop into a major global health concern. NAFLD is closely linked to the modern, unhealthy lifestyle. The Western diet, characterized by excessive energy intake, frequent consumption of red meat, processed meat and foods, soft drinks, and sugar-sweetened beverages (SSBs), irregular meal distribution throughout the day, and unhealthy ways of cooking, predisposes to development of NAFLD. Low levels of physical activity and prolonged sedentary time are additional lifestyle risk factors for NAFLD. Given the present lack of effective pharmacological treatment, lifestyle modifications are regarded as the cornerstone of NAFLD management. Reducing daily calorie intake together with following the Mediterranean diet (MD) is an increasingly accepted approach. Furthermore, increasing the level of physical activity and limiting sedentary behavior are additional measures proposed to improve the outcomes of the disease. Apart from being affected by lifestyle, NAFLD may also affect patients' quality of life (QoL), mostly in the domain of physical function. In this regard, while the early and more benign form of the disease, i.e., simple hepatic steatosis, may not affect QoL, there is evidence, though conflicting, of the impact of nonalcoholic steatohepatitis (NASH) on this index, with, however, most studies showing that QoL is consistently affected in advanced disease, i.e., hepatic fibrosis, cirrhosis, and hepatocellular carcinoma. Considering all the above, appropriate management of lifestyle is likely to attenuate the severity of the disease and improve the QoL of NAFLD patients.

Favorable association between Mediterranean diet (MeD) and DASH with NAFLD among Iranian adults of the Amol Cohort Study (AmolCS)

Nonalcoholic fatty liver disease (NAFLD) is an emerging cause of chronic liver diseases and a major health problem worldwide. Dietary patterns may play a critical role in controlling and preventing this disease, but the available evidence is scarce. The current study aims to ascertain the association of adherence to the Dietary Approach to Stop Hypertension (DASH) diet and Mediterranean diet (MeD) with nonalcoholic fatty liver disease (NAFLD) among Iranian adults of the Amol Cohort Study (AmolCS). In a cross-sectional analysis among 3220 adults (55.3% men), age ≥ 18 years (46.96 ± 14.67), we measured usual dietary intake with a validated food frequency questionnaire (FFQ) and then calculated dietary pattern scores for DASH and MeD. Sociodemographic and lifestyle factors were collected by a structured questionnaire. The presence and degree of NAFLD were also determined by abdominal sonography. Multiple regression models were used to estimate NAFLD odds across tertiles of DASH and Mediterranean dietary scores. Dietary DASH and Mediterranean components were adjusted for total energy intake, based on the residual methods. After adjusting for multiple potential confounders, we found an inverse association of DASH and MeD with NAFLD (Ptrend = 0.02, and Ptrend = 0.002, respectively). Those in the highest tertiles of adherence to the DASH and MeD had the lowest risk for NAFLD (OR = 0.80, 95%CI = 0.66–0.96, OR = 0.64, 95%CI = 0.52–0.78, respectively). The results of logistic analysis of MeD, stratified by gender and abdominal obesity, revealed the favorable association was more pronounced in women (OR = 0.42, 95%CI = 0.29–0.61, Ptrend = 0.004), and in participants with or without abdominal obesity (OR = 0.62, 95% CI = 0.47–0.81, Ptrend = 0.03, OR = 0.64, 95%CI = 0.475–0.91, Ptrend = 0.04, respectively). Similar results were obtained for the adherence to DASH diet score with the prevalence of NAFLD patients with abdominal obesity (OR = 0.75, 95% CI = 0.57–0.97, Ptrend = 0.04). The findings suggested the favorable association between DASH and MeD with NAFLD in Iranian adults, especially women and subjects with or without abdominal obesity. Further prospective investigations are needed to confirm the integrity of our findings.

Moderation effect of economic status in the association between early life famine exposure and MAFLD in adulthood

BACKGROUND & AIMS

The double burden of malnutrition (DBM) in China resulted in high prevalence of diet-related non-communicable diseases. The aim of this study was to analyse the moderation of economic status in the association between early famine exposure and metabolic dysfunction associated with fatty liver disease (MAFLD) in adulthood.

METHODS

10 190 participants in the SPECT-China study enrolled from 2014 to 2016 were included in this study. Participants with fetal famine exposure (birth year 1959-1962) or early-childhood famine exposure (birth year 1955-1958) formed the exposure group. The associations with MAFLD were assessed via regression analyses.

RESULTS

In men, economic status could not moderate the association between early life famine and MAFLD after adjusting for age, excess alcohol drinking, current smokers, famine severity, waist circumference, diabetes, hypertension, and dyslipidemia (P for interaction = .52). However, in women and in the total population, economic status could moderate the association between early life famine and MAFLD after adjusting for the above confounders (P for interaction = .01). In the total population and in women, early life famine exposure was associated with MAFLD in both low economic status and high economic status. However, in men, early life famine exposure was not associated with MAFLD in low economic status, while in high economic status, early-childhood famine exposure was associated with MAFLD.

CONCLUSIONS

Economic status could moderate the association between early life famine exposure and MAFLD in total population and in women.

Weight loss interventions and nonalcoholic fatty liver disease: Optimizing liver outcomes

The growth in prevalence of obesity, type 2 diabetes and nonalcoholic fatty liver disease (NAFLD) has become one of the most important global health challenges. The three chronic diseases are closely linked in their epidemiology and pathophysiology. Currently, weight loss is the most effective treatment for NAFLD (even in the minority of patients with NAFLD who do not have obesity) and is recommended in all national and international guidelines. Accumulating evidence has shown that weight loss, whether achieved by diet and lifestyle interventions, bariatric surgery or pharmacotherapy, can improve biomarkers of NAFLD, as well as prevent progression and, in some cases, reverse fibrosis. There is a dose dependency of weight loss with NAFLD improvement. Pharmacotherapy with antiobesity medications, alone or in combination with intensive lifestyle interventions or other weight-loss drugs, is closing the efficacy gap between diet and exercise and weight-loss surgery in efficacy at reversing obesity. Given the importance of providing effective weight-loss treatment to patients with NAFLD, weight management services need to be made increasingly available and embedded within hepatology services. This narrative review addresses the evidence that weight loss optimizes liver outcomes in people with NAFLD.

Advancements in the treatment of non-alcoholic fatty liver disease (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) is a series of diseases, involving excessive lipid deposition in the liver and is often accompanied by obesity, diabetes, dyslipidemia, abnormal blood pressure, and other metabolic disorders. In order to more accurately reflect its pathogenesis, an international consensus renamed NAFLD in 2020 as metabolic (dysfunction) associated with fatty liver disease (MAFLD). The changes in diet and lifestyle are recognized the non-drug treatment strategies; however, due to the complex pathogenesis of NAFLD, the current drug therapies are mainly focused on its pathogenic factors, key links of pathogenesis, and related metabolic disorders as targets. There is still a lack of specific drugs. In clinical studies, the common NAFLD treatments include the regulation of glucose and lipid metabolism to protect the liver and anti-inflammation. The NAFLD treatments based on the enterohepatic axis, targeting gut microbiota, are gradually emerging, and various new metabolism-regulating drugs are also under clinical development. Therefore, this review article has comprehensively discussed the research advancements in NAFLD treatment in recent years.

The Dietary Inflammatory Index and hepatic health in the US adult population

BACKGROUND

There is limited evidence on the role of an anti-/pro-inflammatory diet in the prevention of non-alcoholic fatty liver disease (NAFLD). We aimed (i) to assess the anti-inflammatory diet profile and its association with transient elastography parameters, including liver stiffness measurement (LSM) and controlled attenuation parameter (CAP), and (ii) to analyse the relationship between the anti-inflammatory diet and surrogate markers of liver disease in a multiethnic US population.

METHODS

A cross-sectional study was conducted on a nationally representative population of 4189 US adults aged 20-80 years. A FibroScan® 502 V2 device (Echosens) was used to estimate the CAP and LSM. Liver markers, including the aspartate transaminase (AST) to alanine transaminase (ALT) ratio, fatty liver index (FLI) and fibrosis-4 score, were also calculated. The Dietary Inflammatory Index (DII) was calculated using a 24-h diet recall.

RESULTS

Lower DII scores (anti-inflammatory diet) were associated with a lower AST:ALT ratio (p < 0.001) and FLI (p < 0.036) after adjusting for covariates. Linear regression analysis revealed that gamma-glutamyl transferase levels (β = 1.702, 95% confidence interval [CI] = 0.325-3.080, p = 0.015), ALT levels (β = -0.616, 95% CI = -1.097 to -0.135, p = 0.012), AST:ALT ratio (β = 0.025, 95% CI = 0.014-0.036, p < 0.001) and FLI (β = 1.168, 95% CI = 0.224-2.112, p = 0.015) were significantly associated with the DII in the multivariable-adjusted model. Participants in the highest anti-inflammatory tertile had the lowest odds ratio (OR) for NAFLD assessed by FLI in both unadjusted (OR = 0.652, 95% CI = 0.539-0.788, p ≤ 0.001) and adjusted models (OR = 0.722, 95% CI = 0.537-0.972, p = 0.032). For the transient elastography parameters (LSM and CAP), no significant associations were identified.

CONCLUSIONS

There was no relationship between the transient elastography parameters and the anti-inflammatory diet profile, although our study showed an association between higher pro-inflammatory properties of diet and poorer hepatic health assessed by surrogate markers of liver disease. Therefore, strategies to promote an anti-inflammatory diet should be considered to prevent NAFLD in adults.

The Hepatic Sinusoid in Chronic Liver Disease: The Optimal Milieu for Cancer

Simple Summary

During the development of chronic liver disease, the hepatic sinusoid undergoes major changes that further compromise the hepatic function, inducing persistent inflammation and the formation of scar tissue, together with alterations in liver hemodynamics. This diseased background may induce the formation and development of hepatocellular carcinoma (HCC), which is the most common form of primary liver cancer and a major cause of mortality. In this review, we describe the ways in which the dysregulation of hepatic sinusoidal cells—including liver sinusoidal cells, Kupffer cells, and hepatic stellate cells—may have an important role in the development of HCC. Our review summarizes all of the known sinusoidal processes in both health and disease, and possible treatments focusing on the dysregulation of the sinusoid; finally, we discuss how some of these alterations occurring during chronic injury are shared with the pathology of HCC and may contribute to its development.

Abstract

The liver sinusoids are a unique type of microvascular beds. The specialized phenotype of sinusoidal cells is essential for their communication, and for the function of all hepatic cell types, including hepatocytes. Liver sinusoidal endothelial cells (LSECs) conform the inner layer of the sinusoids, which is permeable due to the fenestrae across the cytoplasm; hepatic stellate cells (HSCs) surround LSECs, regulate the vascular tone, and synthetize the extracellular matrix, and Kupffer cells (KCs) are the liver-resident macrophages. Upon injury, the harmonic equilibrium in sinusoidal communication is disrupted, leading to phenotypic alterations that may affect the function of the whole liver if the damage persists. Understanding how the specialized sinusoidal cells work in coordination with each other in healthy livers and chronic liver disease is of the utmost importance for the discovery of new therapeutic targets and the design of novel pharmacological strategies. In this manuscript, we summarize the current knowledge on the role of sinusoidal cells and their communication both in health and chronic liver diseases, and their potential pharmacologic modulation. Finally, we discuss how alterations occurring during chronic injury may contribute to the development of hepatocellular carcinoma, which is usually developed in the background of chronic liver disease.

Low levels of Lysosomal Acid Lipase (LAL) activity increases necroinflammation in adult patients with biopsy-proven metabolic associated fatty liver disease

INTRODUCTION AND OBJECTIVE

Metabolic associated fatty liver disease (MAFLD), characterized by intra-hepatic fat accumulation, will soon be the leading cause of end-stage liver disease. Lysosomal Acid Lipase (LAL) is a key enzyme in lipid metabolism. We investigated its activity in patients with biopsy-proven MAFLD.

METHODS

Prospective cross-sectional study in patients with biopsy-proven MAFLD. Blood LAL-activity (pmol/punch/h) was measured with dried blood spot extracts using Lalistat 2. Demographic, clinical, and laboratory data were collected.

RESULTS

101 adult patients were recruited. Among them, 11.9% had a diagnosis of MAFLD without steatohepatitis and 88.1% had MAFLD with steatohepatitis. The median of LAL-activity in patients with MAFLD was 76.8 pmol/punch/h. MAFLD patients with steatohepatitis showed an increase in gamma-glutamyl transferase (p = 0.042), insulin (p = 0.001), homeostatic model assessment for insulin resistance (HOMA-IR, p = 0.001) and advanced liver fibrosis (p < 0.001), compared to cases of MAFLD without steatohepatitis. There was no statistical difference in LAL-activity between the cases (p = 0.296). When considering LAL-activity above and below 77 pmol/punch/h as a cut-off value, patients with reduced LAL-activity had a significant increase in necroinflammatory activity according to the METAVIR score (p = 0.040), and NAFLD activity score (NAS, p = 0.031) compared to cases with higher LAL-activity.

CONCLUSION

Our findings suggest that reduced LAL-activity is associated with increased necroinflammatory activity and severity of the NAS. A better knowledge of the role of LAL may provide new insights into the pathogenesis and progression of MAFLD.

Diet and exercise in NAFLD/NASH: Beyond the obvious

Lifestyle represents the most relevant factor for non-alcoholic fatty liver disease (NAFLD) as the hepatic manifestation of the metabolic syndrome. Although a tremendous body of clinical and preclinical data on the effectiveness of dietary and lifestyle interventions exist, the complexity of this topic makes firm and evidence-based clinical recommendations for nutrition and exercise in NAFLD difficult. The aim of this review is to guide readers through the labyrinth of recent scientific findings on diet and exercise in NAFLD and non-alcoholic steatohepatitis (NASH), summarizing "obvious" findings in a holistic manner and simultaneously highlighting stimulating aspects of clinical and translational research "beyond the obvious". Specifically, the importance of calorie restriction regardless of dietary composition and evidence from low-carbohydrate diets to target the incidence and severity of NAFLD are discussed. The aspect of ketogenesis-potentially achieved via intermittent calorie restriction-seems to be a central aspect of these diets warranting further investigation. Interactions of diet and exercise with the gut microbiota and the individual genetic background need to be comprehensively understood in order to develop personalized dietary concepts and exercise strategies for patients with NAFLD/NASH.

The effect of a Mediterranean diet vs. a low-fat diet on non-alcoholic fatty liver disease in children: a randomized trial

Non-alcoholic fatty liver disease (NAFLD) is becoming ever more common in children, due to the increasing global prevalence of obesity. The first-line treatment consists of weight loss through a combination of a healthy diet and exercise. The objective of this study was to determine the effects of a Mediterranean Diet or a low-fat diet on reducing hepatic steatosis and insulin resistance in children with NAFLD. This 12-week randomised clinical trial was conducted with children aged 9-17 years diagnosed with NAFLD and randomised into either a Mediterranean Diet or a low-fat diet group. By the end of the study, hepatic steatosis had decreased significantly in both groups (p < 0.001). Liver enzymes also improved significantly, while significant decreases were observed in insulin resistance in both groups, although this decrease was greater in the Mediterranean Diet group (p = 0.010). This study demonstrated that a decrease in hepatic steatosis and an improvement in insulin sensitivity can be achieved with both a Mediterranean Diet and a low-fat diet over 12 weeks, with no significant decrease in the energy required for growth, in children with NAFLD.

Treatment of Hepatocellular Carcinoma with Immune Checkpoint Inhibitors and Applicability of First-Line Atezolizumab/Bevacizumab in a Real-Life Setting

Immune checkpoint inhibitors (ICIs) are the new frontier for the treatment of advanced hepatocellular carcinoma (HCC). Since the first trial with tremelimumab, a cytotoxic T-lymphocyte-associated protein 4 inhibitor, increasing evidence has confirmed that these drugs can significantly extend the survival of patients with advanced hepatocellular carcinoma (HCC). As a matter of fact, the overall survival and objective response rates reported in patients with advanced HCC treated with ICIs are the highest ever reported in the second-line setting and, most recently, the combination of the anti-programmed death ligand protein-1 atezolizumab with bevacizumab-an anti-vascular endothelial growth factor monoclonal antibody-demonstrated superiority to sorafenib in a Phase III randomized clinical trial. Therefore, this regimen has been approved in several countries as first-line treatment for advanced HCC and is soon expected to be widely used in clinical practice. However, despite the promising results of trials exploring ICIs alone or in combination with other agents, there are still some critical issues to deal with to optimize the prognosis of advanced HCC patients. For instance, the actual proportion of patients who are deemed eligible for ICIs in the real-life ranges from 10% to 20% in the first-line setting, and is even lower in the second-line scenario. Moreover, long-term data regarding the safety of ICIs in the population of patients with cirrhosis and impaired liver function are lacking. Lastly, no biomarkers have been identified to predict response, and thus to help clinicians to individually tailor treatment. This review aimed to summarize the state of the art immunotherapy in HCC and, by analyzing a large, multicenter cohort of Italian patients with HCC, to assess the potential applicability of the combination of atezolizumab/bevacizumab in the real-life setting.

Effect of Mediterranean diet on liver enzymes: a systematic review and meta-analysis of randomised controlled trials

Elevated levels of liver enzymes are the main markers of liver dysfunction. Liver enzymes are the important indicators of non-alcoholic fatty liver disease (NAFLD) in the general population. Previous randomised clinical trials (RCT) investigated the effects of Mediterranean diet (MedDiet) as a plant-based diet on features of NAFLD like liver enzymes, but their results are contradictory. This study aimed to systematically review and meta-analyse RCT investigating the effect of MedDiet on liver enzymes. PubMed, Web of Science, Scopus and Google Scholar were searched until December 2020. A total of ten RCT (n 705 participants) evaluating the effect of MedDiet on liver enzymes including aspartate aminotransferase (AST), alanine transaminase (ALT) and γ-glutamyltransferase (GGT) were included. A random effects model was used to estimate the pooled effect size. To evaluate the heterogeneity among the included studies, the Cochran's Q-test and I-squared test were used. The MedDiet significantly reduced AST (weighted mean difference (WMD) = -0·38 IU/l; 95 % CI - 0·73, -0·03 IU/l; P = 0·03) and GGT (WMD = -0·16 IU/l; 95 % CI - 0·32, -0·006 IU/l; P = 0·04) but had no significant effect on ALT (WMD = -0·55 IU/l; 95 % CI - 1·25, 0·13 IU/l; P = 0·11). However, sensitivity analysis revealed that the overall effects of MedDiet on AST, GGT and ALT were significantly influenced by removing some studies. There was no publication bias based on Begg's and Egger's tests. Generally, MedDiet can improve liver enzymes. To better conclusion, further RCT investigating the effect of MedDiet on liver enzymes, especially in patients with NAFLD, are still required.

Beyond the Paradigm of Weight Loss in Non-Alcoholic Fatty Liver Disease: From Pathophysiology to Novel Dietary Approaches

Current treatment recommendations for non-alcoholic fatty liver disease (NAFLD) rely heavily on lifestyle interventions. The Mediterranean diet and physical activity, aiming at weight loss, have shown good results in achieving an improvement of this liver disease. However, concerns related to compliance and food accessibility limit the feasibility of this approach, and data on the long-term effects on liver-related outcomes are lacking. Insulin resistance is a central aspect in the pathophysiology of NAFLD; therefore, interventions aiming at the improvement of insulin sensitivity may be preferable. In this literature review, we provide a comprehensive summary of the available evidence on nutritional approaches in the management of NAFLD, involving low-calorie diets, isocaloric diets, and the novel schemes of intermittent fasting. In addition, we explore the harmful role of single nutrients on liver-specific key metabolic pathways, the role of gene susceptibility and microbiota, and behavioral aspects that may impact liver disease and are often underreported in clinical setting. At present, the high variability in terms of study populations and liver-specific outcomes within nutritional studies limits the generalizability of the results and highlights the urgent need of a tailored and standardized approach, as seen in regulatory trials in Non-Alcoholic Steatohepatitis (NASH).

The Significance of the Mediterranean Diet in the Management of Non-Alcoholic Fatty Liver Disease: A Systematic Review

Non-alcoholic fatty liver disease (NAFLD) is the accumulation of intrahepatic fat occurring in the absence of alcohol abuse. The fatty changes in the liver are often the beginning of sequelae of complications, potentially causing steatohepatitis, liver cirrhosis, and hepatocellular carcinoma. The Mediterranean diet is not only a way of eating but is considered a lifestyle and primarily consists of a plant-based diet, with olive oil as the primary lipid. In this study, we reviewed the effectiveness of the Mediterranean diet on NAFLD and its efficacy in disease management. This systematic review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol (PRISMA-P) 2009 guidelines. The PubMed database was used to gather articles, using the following terms individually and in combination, "Mediterranean diet," "non-alcoholic fatty liver disease," "insulin resistance," "metabolic syndrome," "omega-3-fatty acids." A quality appraisal was completed to include 14 articles in this systematic review. The studies discuss the correlation between the Mediterranean diet and its role in preventing and treating NAFLD. Olive oil is the major monounsaturated fatty acid, whereas nuts, seeds, and fish consist largely of polyunsaturated fatty acids, both of which are essential components of the Mediterranean diet. The plant-based diet, having sufficient amounts of vegetables, legumes, and fruits, provides its anti-oxidant and anti-inflammatory effects, playing a fundamental role in preventing oxidative stress damage. Olive oil polyphenols increase apoptosis and cell cycle arrest. They also decrease proliferation and angiogenesis, all of which prevent neoplasia. Adapting the Mediterranean lifestyle has shown promising effects in NAFLD, reducing overall mortality and morbidity.

Perspectives on Precision Medicine Approaches to NAFLD Diagnosis and Management

Precision medicine defines the attempt to identify the most effective approaches for specific subsets of patients based on their genetic background, clinical features, and environmental factors. Nonalcoholic fatty liver disease (NAFLD) encompasses the alcohol-like spectrum of liver disorders (steatosis, steatohepatitis with/without fibrosis, and cirrhosis and hepatocellular carcinoma) in the nonalcoholic patient. Recently, disease renaming to MAFLD [metabolic (dysfunction)-associated fatty liver disease] and positive criteria for diagnosis have been proposed. This review article is specifically devoted to envisaging some clues that may be useful to implementing a precision medicine-oriented approach in research and clinical practice. To this end, we focus on how sex and reproductive status, genetics, intestinal microbiota diversity, endocrine and metabolic status, as well as physical activity may interact in determining NAFLD/MAFLD heterogeneity. All these factors should be considered in the individual patient with the aim of implementing an individualized therapeutic plan. The impact of considering NAFLD heterogeneity on the development of targeted therapies for NAFLD subgroups is also extensively discussed.

Mechanisms of Non-Alcoholic Fatty Liver Disease in the Metabolic Syndrome. A Narrative Review

Non-alcoholic fatty liver disease (NAFLD) and metabolic syndrome (MS) are two different entities sharing common clinical and physio-pathological features, with insulin resistance (IR) as the most relevant. Large evidence leads to consider it as a risk factor for cardiovascular disease, regardless of age, sex, smoking habit, cholesterolemia, and other elements of MS. Therapeutic strategies remain still unclear, but lifestyle modifications (diet, physical exercise, and weight loss) determine an improvement in IR, MS, and both clinical and histologic liver picture. NAFLD and IR are bidirectionally correlated and, consequently, the development of pre-diabetes and diabetes is the most direct consequence at the extrahepatic level. In turn, type 2 diabetes is a well-known risk factor for multiorgan damage, including an involvement of cardiovascular system, kidney and peripheral nervous system. The increased MS incidence worldwide, above all due to changes in diet and lifestyle, is associated with an equally significant increase in NAFLD, with a subsequent rise in both morbidity and mortality due to both metabolic, hepatic and cardiovascular diseases. Therefore, the slowdown in the increase of the "bad company" constituted by MS and NAFLD, with all the consequent direct and indirect costs, represents one of the main challenges for the National Health Systems.

Pyridoxamine and Caloric Restriction Improve Metabolic and Microcirculatory Abnormalities in Rats with Non-Alcoholic Fatty Liver Disease

INTRODUCTION

This study aims to examine the effect of a diet intervention and pyridoxamine (PM) supplementation on hepatic microcirculatory and metabolic dysfunction in nonalcoholic fatty liver disease (NAFLD).

METHODS

NAFLD in Wistar rats was induced with a high-fat diet for 20 weeks (NAFLD 20 weeks), and control animals were fed with a standard diet. The NAFLD diet intervention group received the control diet between weeks 12 and 20 (NAFLD 12 weeks), while the NAFLD 12 weeks + PM group also received PM. Fasting blood glucose (FBG) levels, body weight (BW), visceral adipose tissue (VAT), and hepatic microvascular blood flow (HMBF) were evaluated at the end of the protocol.

RESULTS

The NAFLD group exhibited a significant increase in BW and VAT, which was prevented by the diet intervention, irrespective of PM treatment. The FBG was elevated in the NAFLD group, and caloric restriction improved this parameter, although additional improvement was achieved by PM. The NAFLD group displayed a 31% decrease in HMBF, which was partially prevented by caloric restriction and completely prevented when PM was added. HMBF was negatively correlated to BW, FBG, and VAT content.

CONCLUSION

PM supplementation in association with lifestyle modifications could be an effective intervention for metabolic and hepatic vascular complications.

Non-Alcoholic Fatty Liver Disease: From Pathogenesis to Clinical Impact

Non-Alcoholic Fatty Liver Disease (NAFLD) is caused by the accumulation of fat in over 5% of hepatocytes in the absence of alcohol consumption. NAFLD is considered the hepatic manifestation of metabolic syndrome (MS). Recently, an expert consensus suggested as more appropriate the term MAFLD (metabolic-associated fatty liver disease). Insulin resistance (IR) plays a key role in the development of NAFLD, as it causes an increase in hepatic lipogenesis and an inhibition of adipose tissue lipolysis. Beyond the imbalance of adipokine levels, the increase in the mass of visceral adipose tissue also determines an increase in free fatty acid (FFA) levels. In turn, an excess of FFA is able to determine IR through the inhibition of the post-receptor insulin signal. Adipocytes secrete chemokines, which are able to enroll macrophages inside the adipose tissue, responsible, in turn, for the increased levels of TNF-α. The latter, as well as resistin and other pro-inflammatory cytokines such as IL-6, enhances insulin resistance and correlates with endothelial dysfunction and an increased cardiovascular (CV) risk. In this review, the role of diet, intestinal microbiota, genetic and epigenetic factors, low-degree chronic systemic inflammation, mitochondrial dysfunction, and endoplasmic reticulum stress on NAFLD have been addressed. Finally, the clinical impact of NAFLD on cardiovascular and renal outcomes, and its direct link with type 2 diabetes have been discussed.

Calorie-Restricted Mediterranean and Low-Fat Diets Affect Fatty Acid Status in Individuals with Nonalcoholic Fatty Liver Disease

Lifestyle modifications are the main support of nonalcoholic fatty liver disease (NAFLD) therapy. Weight loss is one of the primary goals in NAFLD, but the effects of different calorie-restricted diets remain unclear. Thus, we evaluated the effects of two calorie-restricted diets—the Mediterranean diet (Med diet) and low-fat diet—on liver status, cardiometabolic markers, and fatty acid profiles in patients with NAFLD. Twenty-four overweight/moderately obese men were randomly assigned to consume one of these diets. Lipid levels, glucose, insulin, liver enzymes, steatosis, and fatty acid profiles of serum and erythrocytes phospholipids were assessed. After 3 months, all participants had a significant weight loss (>9%), with improvements in waist circumference, body fat %, index of visceral adiposity (VAI), lipid accumulation product, fatty liver (FLI), and hepatic steatosis (HSI) index (p < 0.001). Both diets significantly lowered triglycerides, total and LDL-cholesterol, liver enzymes, fasting glucose, insulin, and HOMA-IR index. Fatty acid profiles were enhanced after both diets, with a significantly decreased n-6/n-3 ratio. Participants on the Med diet had higher levels of HDL-cholesterol and monounsaturated and n-3 docosahexaenoic acids in serum phospholipids and lower levels of saturated fatty acids, triglycerides, TG/HDL ratio, and FLI when compared to participants on the low-fat diet. Our results indicate that dietary patterns and calorie restriction represent central therapeutic issues in the improvement of obesity-related cardiometabolic alterations that are involved in the mechanism of hepatic steatosis. The Med diet may contribute to disease treatment even more than the low-fat diet since it leads to decreased saturated and increased monounsaturated and n-3 polyunsaturated fatty acid status and improved FLI in NAFLD patients.

Nuts and Non-Alcoholic Fatty Liver Disease: Are Nuts Safe for Patients with Fatty Liver Disease?

Diet and lifestyle interventions are the recommended treatment for patients with non-alcoholic fatty liver disease (NAFLD), with the aim of achieving a 7-10% weight loss. Several dietary patterns have been suggested for this purpose, however, to date, the best one is represented by the Mediterranean diet (MD) as it is rich in macro- and micro- nutrients known for their effectiveness in health-promotion and cardio-vascular disease prevention. Moreover, MD is characterized by the inclusion of nuts. These foods have shown potential benefits in health-promotion as they are rich in fibers, which have lipid-lowering effects, rich in mono- and poly-unsaturated fatty acids, which help reduce insulin-resistance and serum cholesterol, and contain anti-oxidants which reduce oxidative stress and inflammation. Additionally, nuts are associated with a better control, or reduction, of Body Mass Index (BMI). All these effects are useful targets to achieve in NAFLD, so that nuts have been proposed as a suitable dietary treatment supplement for weight and metabolic control in these patients. In recent years, health authorities raised an alert on nuts consumption as these may be at high risk of aflatoxin (AF) contamination, for which controls and legislations are different among countries. AF is a well-known cancerogenic agent and a recognized risk factor for hepatocellular carcinoma. Patients with NAFLD have an overall, inherent sevenfold increased risk of developing hepatocellular carcinoma as compared with the general population. In this context, one could argue that recommending the inclusion of nuts in the diet of NAFLD patients has to be balanced with the risk of potential chronic exposure to AF, and every effort should be pursued to assure the safety of these nutrients. In this review, we aim to summarize the benefits of nuts consumption, the evidence for AF contamination of nuts and the consequent potential risks in patients with NAFLD.