The impact of health status, diet and lifestyle on non-alcoholic fatty liver disease: Narrative review

Diet-pathobiont interplay in health and inflammatory bowel disease

The intestinal microbiota plays a crucial role in maintaining host health by participating in various beneficial functions. However, under certain conditions, it can contribute to the development of inflammatory bowel disease (IBD) and other chronic inflammatory conditions. Importantly, not all commensal microbiota members are drivers of inflammation. A specific subset of commensal bacteria, known as pathobionts, can exhibit pathogenic potential under specific circumstances. Their inflammatory potential is modulated by several factors, including the host's genetic background and the surrounding microbiota. Furthermore, diet has emerged as a critical factor influencing the gut microbiota, with some studies highlighting its role in modulating pathobionts. This review will delve into the role played by pathobionts in chronic intestinal inflammation, in both mouse models as well as in humans, with a focus on the interplay between dietary factors and pathobiont members of the intestinal microbiota. Understanding the complex relationships between diet, pathobionts, and chronic inflammation could pave the way for diet-based therapeutic strategies aimed at managing chronic inflammatory conditions.

Caffeine intake associated with a lower risk of liver fibrosis in different glucose status

BACKGROUND AND AIMS

To investigate the prevalence of liver fibrosis, and the association between caffeine intake and fibrosis in populations with different glucose metabolism status.

METHODS

This was a cross-sectional study based on the National Health and Nutrition Examination Survey (2005-March 2020). Of the 39,221 adult individuals with no necessary laboratory results missing, a total of 23,711 eligible individuals were included in the study. Individuals were divided into T2DM, prediabetes, and diabetes-free groups. Fibrosis-4 index was calculated to evaluate the risk of liver fibrosis. Caffeine intake was obtained through a 24-hour dietary recall.

RESULTS

The mean ± SE age of prediabetes group was 53 ± 0·4 years, and in type 2 diabetes mellitus group, the individuals have a mean ± SE age of 62 ± 0·3 years. The participants with type 2 diabetes mellitus had significantly higher risk of liver fibrosis than those with prediabetes or normal glucose tolerance (5·9% vs. 3·2% vs. 2·5%, P < 0·001). Compared to individuals with daily caffeine intake < 78 mg, individuals with daily caffeine intake ≥ 78 mg had significantly lower risk of liver fibrosis in all subgroups (odds ratio: diabetes-free group: 0·698[0·577-0·846]; prediabetes group: 0·553[0·397-0·769]; type 2 diabetes mellitus group: 0·720[0·556-0·933]; all P < 0·05).

CONCLUSIONS

Prevalence of liver fibrosis is high in patients with type 2 diabetes mellitus and prediabetes. It is indicated that individuals with prediabetes should also be screened for fibrosis. Caffeine intake ≥ 78 mg per day is associated with a lower risk of liver fibrosis.

Metabolic Dysfunction-Associated Steatotic Liver Disease Is Accompanied by Increased Activities of Superoxide Dismutase, Catalase, and Carbonyl Reductase 1 and Levels of miR-200b-3p in Mouse Models

Metabolic dysfunction-associated steatotic liver disease (MASLD), one of the leading causes of chronic liver disorders, is characterized by hepatic lipid accumulation. MASLD causes alterations in the antioxidant defense system, lipid, and drug metabolism, resulting in impaired antioxidant status, hepatic metabolic processes, and clearance of therapeutic drugs, respectively. In the MASLD pathogenesis, dysregulated epigenetic mechanisms (e.g., histone modifications, DNA methylation, microRNAs) play a substantial role. In this study, the development of MASLD was investigated in mice fed a high-fat, high-fructose, and high-cholesterol (FFC) diet from 2 months of age, mice treated neonatally with monosodium glutamate (MSG) on a standard diet (STD), and mice treated with MSG on an FFC diet at 7 months of age and compared to control mice (C) on STD. Changes in liver histology, detoxification enzymes, epigenetic regulation, and genes involved in lipid metabolism were characterized and compared. The strong liver steatosis was observed in MSG STD, C FFC, and MSG FFC, with significant fibrosis in the latter one. Moreover, substantial alterations in hepatic lipid metabolism, epigenetic regulatory factors, and expressions and activities of various detoxification enzymes (namely superoxide dismutase, catalase, and carbonyl reductase 1) were observed in MASLD mice compared to control mice. miR-200b-3p, highly significantly upregulated in both FFC groups, could be considered as a potential diagnostic marker of MASLD. The MSG mice fed FFC seem to be a suitable model of MASLD characterized by both liver steatosis and fibrosis and substantial metabolic dysregulation.

Investigation on the lipid-lowering effect and mechanism by combining turmeric with hawthorn in C57BL/6 obese mice

Study on the hypolipidemic effect of turmeric combined with hawthorn on C57BL/6 obese mice and its possible mechanism. C57 mice were fed with 60% high-fat diet for 8 weeks to establish an obesity model, and 4 mice were slaughtered to verify whether the modeling was successful. The successful mice were divided into model group (HFD), positive group (high fat feed group [HFD] + simvastatin group [SIM]), turmeric group (HFD + TUR), hawthorn group (HFD + HAW), and para-medicine group (HFD + para-drug group [DOU]) for 4 weeks by gavage intervention. Different intervention groups had certain lipid-lowering effects, and the para-medicine group showed significant differences (p < 0.05, p < 0.01, p < 0.001) in reducing serum total cholesterol, triglycerides, low-density lipoprotein cholesterol, glutamic acid transaminase (ALT), glutamic acid transaminase (AST), and increasing high-density lipoprotein cholesterol. In the para-medicine group, the protein expression of peroxisome proliferator-activated receptor γ, fatty acid synthase, platelet-reactive protein receptor 36, and CCAAT/enhancer binding protein α were significantly downregulated, and the protein expression of carnitine palmitoyl transferase1 and peroxisome proliferator-activated receptor α protein expression (p < 0.01, p < 0.001), thus suggesting that turmeric and hawthorn are superior to turmeric and hawthorn alone in enhancing lipid metabolism-related mechanisms. Combined effects of turmeric and hawthorn improve lipid metabolism in mice, protect the liver, and improve the protein expression of liver-related genes. This study can lay the theoretical basis for the future association of medicinal food products and the development of related weight loss products.

An update on the therapeutic role of RNAi in NAFLD/NASH

Unhealthy lifestyles have given rise to a growing epidemic of metabolic liver diseases, including nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). NAFLD often occurs as a consequence of obesity, and currently, there is no FDA-approved drug for its treatment. However, therapeutic oligonucleotides, such as RNA interference (RNAi), represent a promising class of pharmacotherapy that can target previously untreatable conditions. The potential significance of RNAi in maintaining physiological homeostasis, understanding pathogenesis, and improving metabolic liver diseases, including NAFLD, is discussed in this article. We explore why NAFLD/NASH is an ideal target for therapeutic oligonucleotides and provide insights into the delivery platforms of RNAi and its therapeutic role in addressing NAFLD/NASH.

Emerging Perspectives on the Set of Conditions That Lead to the Emergence of Metabolic Syndrome

Metabolic syndrome, as a medical condition, presents multifactorial complexity that is characterized by the resulting damage from genetic, environmental, and lifestyle factors (presence or absence of physical activity, food choices). Thus, metabolic syndrome qualifies unequivocally as a medical condition in which there are, simultaneously, several independent metabolic risk factors, namely, abdominal obesity, high triglyceride level, low HDL cholesterol level, arterial hypertension, and high glycemic level. Although age, sex, socio-economic status, and the precise definition of metabolic syndrome all influence the prevalence and risk of developing the condition, clinical and epidemiological studies clearly show that central obesity, as measured by an increased abdominal circumference, is the main risk factor. Thus, due to the growing global incidence of obesity, there has been an increase in the incidence of metabolic syndrome. Starting with obesity, all other metabolic risk factors are influenced: for example, as a result of insulin resistance with hyperglycemia, diabetes is linked to an increased risk of cardiovascular disease due to increased abdominal circumference. Through this review, we aimed to highlight the latest research studies and dietary nutritional interventions useful in the prevention of this disease but also implementation strategies for primary prevention among the healthy population.

The effects of low-fat dairy products fortified with 1500 IU vitamin D3 on serum liver function biomarkers in adults with abdominal obesity: a randomized controlled trial

INTRODUCTION

Vitamin D deficiency has been reported to affect liver function biomarkers. This study was aimed to investigate the effect of consuming vitamin D fortified low-fat dairy products on liver function tests in adults with abdominal obesity.

METHODS

This total blinded randomized controlled trial was undertaken on otherwise healthy abdominally obese adults living in Mashhad, Iran. Milk and yogurt were fortified with 1500 IU vitamin D3 nano-capsules. Participants were randomized to receive fortified milk (n = 73), plain milk (n = 73), fortified yogurt (n = 69), and plain yogurt (n = 74) for 10 weeks. Blood samples were taken at baseline and at the end of the study to assess serum levels of vitamin D, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase (ALP), and Gamma glutamyl transferase.

RESULTS

A total of 289 participants completed the study (54% female). The groups were homogenous in terms of age, sex, weight, energy intake, and physical activity level (p-value > 0.05). After the trial, vitamin D serum levels were significantly increased in both groups receiving fortified products (both p < 0.001). There was a significant time*group effect only in serum ALP (p < 0.001).

CONCLUSION

Consumption of dairy products fortified by 1500 IU vitamin D3 might have detrimental effects on serum levels of some liver enzymes in individuals with abdominal obesity. Further studies needed to determine these effects and underlying mechanisms.

TRIAL REGISTRATION

IRCT20101130005280N27 .

A healthy lifestyle, Life's Essential 8 scores and new-onset severe NAFLD: A prospective analysis in UK Biobank

BACKGROUND

The association of a healthy lifestyle and the American Heart Association (AHA) Life's Essential 8 (LE8) score with the risk of new-onset nonalcoholic fatty liver disease (NAFLD) remains uncertain. We aimed to explore the associations between a healthy lifestyle and higher LE8 scores with new-onset severe NAFLD in the general population.

METHODS

266,645 participants without prior liver diseases were included from the UK Biobank. A healthy lifestyle was determined based on body mass index, smoking, alcohol consumption, physical activity, sleep duration, and diet. LE8 score was generated from 8 metrics according to the AHA cardiovascular health (CVH) advisory, varying from 0 to 100 scores. The primary study outcome was new-onset severe NAFLD. The study outcomes were ascertained by hospital inpatient data, cancer registry, and death register records.

RESULTS

During a median follow-up of 11.9 years, 2284(0.9 %) participants developed severe NAFLD. Compared with those with a poor lifestyle, participants with intermediate (HR, 0.60; 95%CI: 0.55-0.67), or ideal (HR, 0.20; 95%CI: 0.15-0.27) lifestyles had a significantly lower risk of new-onset severe NAFLD. Compared to the low CVH group (LE8 scores: 0-49), the moderate (scores:50-79) (HR, 0.43; 95%CI: 0.39-0.48) and high CVH (scores:80-100) (HR, 0.10; 95%CI: 0.07-0.14) group had a significantly lower risk of new-onset severe NAFLD. Accordingly, adhering to a healthy lifestyle and attaining a high CVH in all individuals could prevent 66.8 % (95%CI: 58.5-75.1 %) and 77.3 % (95%CI:70.4-84.2 %) of severe NAFLD, respectively. Genetic risks of NAFLD did not modify these associations.

CONCLUSION

A favorable lifestyle and a higher LE8 score were significantly associated with a lower risk of new-onset severe NAFLD, independent of genetic risks of NAFLD.

Impact of nonalcoholic fatty liver disease-related metabolic state on depression

Nonalcoholic fatty liver disease (NAFLD), also recently referred as metabolic (dysfunction)-associated fatty liver disease (MAFLD), is characterized by hepatocyte steatosis in the setting of metabolic risk conditions and in the absence of an underlying precursor, for instance alcohol consumption, hepatotropic viruses and hepatotoxic drugs. A possible association between NAFLD and depression has been proposed, owing to intersecting pathophysiological pathways. This narrative review aimed to summarize the current evidence that illustrate the potential pathophysiological and clinical linkage between NAFLD-related metabolic state and depression. Prefrontal cortex lesions are suggested to be a consequence of liver steatosis-associated systematic hyperinflammatory state, a phenomenon also occurring in depression. In addition, depressive symptoms are present in neurotransmitter imbalances. These abnormalities seem to be correlated with NAFLD/MAFLD, in terms of insulin resistance (IR), ammonia and gut dysbiosis' impact on serotonin, dopamine, noradrenaline levels and gamma aminobutyric acid receptors. Furthermore, reduced levels of nesfatin-1 and copine-6-associated BDNF (brain-derived neurotrophic factor) levels have been considered as a probable link between NAFLD and depression. Regarding NAFLD-related gut dysbiosis, it stimulates mediators including lipopolysaccharides, short-chain fatty acids and bile acids, which play significant role in depression. Finally, western diet and IR, which are mainstay components of NAFLD/MAFLD, are, also, substantiated to affect neurotransmitters in hippocampus and produce neurotoxic lipids that contribute to neurologic dysfunction, and thus trigger emotional disturbances, mainly depressive symptoms.

Thwarting Metabolic Dysfunction-Associated Fatty Liver Disease (MAFLD) with Common Bean: Dose- and Sex-Dependent Protection against Hepatic Steatosis

Hepatic steatosis signifies onset of metabolic dysfunction-associated fatty liver disease (MAFLD) caused by disrupted metabolic homeostasis compromising liver function. Regular consumption of common beans reduces the risk of metabolic impairment, but its effective dose, the impact of biological sex, and underlying mechanisms of action are unknown. We fed female and male C57BL6/J mice with obesogenic yet isocaloric diets containing 0%, 17.5%, 35%, and 70% of total dietary protein derived from cooked whole common beans. Liver tissue was collected for histopathology, lipid quantification, and RNA-seq analyses. Beans qualitatively and quantitatively diminished hepatic fat deposition at the 35% dose in female and 70% dose in male mice. Bean-induced differentially expressed genes (DEGs) most significantly mapped to hepatic steatosis and revealed dose-responsive inhibition of de novo lipogenesis markers (Acly, Acaca, Fasn, Elovl6, Scd1, etc.) and triacylglycerol biosynthesis, activation of triacylglycerol degradation, and downregulation of sterol regulatory element-binding transcription factor 1 (SREBF1) signaling. Upregulated fatty acid β-oxidation was more prominent in females, while suppression of Cd36-mediated fatty acid uptake-in males. Sex-dependent bean effects also involved DEGs patterns downstream of peroxisome proliferator-activated receptor α (PPARα) and MLX-interacting protein-like (MLXIPL). Therefore, biological sex determines amount of common bean in the diet required to prevent hepatic lipid accumulation.

Estimation of the Quality of the Diet of Mexican University Students Using DQI-I

The quality of diet can be measured using diet quality indices, based on knowledge of associations between diet and health. The objective of this work was to evaluate whether the International Diet Quality Index is suitable for use as a diet quality index in populations of Mexican university girls. A cross-sectional nutritional survey was conducted at the University of Chihuahua (Mexico), collecting semi-quantitative nutritional information and socio-economic and lifestyle data from a representative sample of 400 women. Mean (Standard Deviation (SD)) age was 21.43 years (SD: 3.72); 59.1% were normal weight, 26.6% overweight, 15.3% obesity. The Diet Quality Index-International (DQI-I) was developed according to the method of Kim et al. (2003) and focused on major aspects of a high-quality diet (variety, adequacy, moderation and overall balance). The total score of Diet Quality Index-International reached 53.86% (SD: 11.43), indicating that the general diet of Mexican women a poor-quality diet. Adequacy scored highest, followed by moderation and variety. Overall balance scored the lowest. Variety: 26.3 % consumed less than 4 food groups daily, only 12.8% take more than 1 serving from each food group, and 50.6% consumed only one source of protein daily. Regarding adequacy, a large proportion of the population reported an intake of proteins, vitamin C, calcium, iron, and fruit greater than 50% of recommendation; the vegetables, fiber and grain groups were less 50%. Poor scores were obtained for total fat and SFA consumption (moderation). No statistically significant differences are observed for any of the variables under study and score of the Diet Quality Index-International: body mass index, weight, physical activity level, education level of father and mother, location of lunch, breakfast considered important, knowledge of nutrition, which allows us to consider a relatively uniform population in its eating habits. These people are close to a Westernized diet, and an intervention in nutritional education would be advisable to improve the intake of unprocessed foods, consume a greater variety of protein sources and significantly reduce consumption of sugary foods and soft drinks. Due to different methodological and cultural factors, the proposed Diet Quality Index-International dietary assessment method does not seem to be useful in the assessment of diet quality in the Mexican university population, so further research is needed to develop a diet quality index adapted to the Mexican population.

MCD Diet Rat Model Induces Alterations in Zinc and Iron during NAFLD Progression from Steatosis to Steatohepatitis

We evaluate the effects of the methionine-choline-deficient (MCD) diet on serum and hepatic zinc (Zn) and iron (Fe) and their relationships with matrix metalloproteinases (MMPs) and their modulators (TIMPs and RECK) as well as hepatic fatty acids using male Wistar rats fed 2-, 4- and 8-week MCD diets. Serum and hepatic Zn decrease after an 8-week MCD diet. Serum Fe increases after an 8-week MCD diet and the same occurs for hepatic Fe. An increase in hepatic MMP activity, associated with a decrease in RECK and TIMPs, is found in the MCD 8-week group. Liver Fe shows a positive correlation versus MMPs and RECK, and an inverse correlation versus TIMPs. A positive correlation is found comparing liver Zn with stearic, vaccenic and arachidonic acids, and an inverse correlation is found with linolenic and docosatetraenoic acids. An opposite trend is found between liver Fe versus these fatty acids. During NAFLD progression from steatosis to steatohepatitis, MCD rats exhibit an increase in Zn and a decrease in Fe levels both in serum and tissue associated with alterations in hepatic MMPs and their inhibitors, and fatty acids. The correlations detected between Zn and Fe versus extracellular matrix modulators and fatty acids support their potential role as therapeutic targets.