Low serum vitamin D concentrations are associated with obese but not lean NAFLD: a cross-sectional study

Current strategies for nonalcoholic fatty liver disease treatment (Review)

Nonalcoholic fatty liver disease (NAFLD), the most common chronic hepatic disease, has become a leading health problem worldwide. The present review summarized the methods and mechanisms to treat NAFLD, including the Mediterranean diet, physical activity and exercise, bariatric surgery and specific therapeutic agents, including statins, peroxisome proliferator‑activated receptor agonists, cenicriviroc and farnesoid X receptor agonists. Biologically active substances, such as peptides, alkaloids, polyphenolic compounds, silymarin, antibiotics, fatty acids, vitamins, probiotics, synbiotics and lamiaceae have also demonstrated actions that combat NAFLD. Considering their different mechanisms of action, combining some of them may prove an efficacious treatment for NAFLD. In this light, the present review describes recent progress and future prospects in treating NAFLD.

Molecular Insights of Nonalcoholic Fatty Liver Disease Pathogenesis

Nonalcoholic fatty liver disease (NAFLD) is now the most prevalent chronic liver disease. Many hepatic abnormalities are associated with NAFLD such as nonalcoholic steatohepatitis, progressive fibrosis, cirrhosis, and liver failure. Moreover, the pathogenesis of NAFLD has numerous etiologies and can be explained due to the existence of several of stimulus that act simultaneously on genetically susceptible patients. These stimuli include obesity, diabetes, and insulin resistance. In addition, identifying the role of gut microbiota on NAFLD progression has been illustrated. In this review, we clarified the several factors that lead to the development of NAFLD and identify those who are most at risk of developing liver end-stage disease. Highlighting the noninvasive diagnostic NAFLD markers could be helpful in the disease prevention and treatment approaches.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Epidemiology of lean/non-obese nonalcoholic fatty liver disease in China: A systematic review and meta-analysis

OBJECTIVES

To assess the prevalence and metabolic characteristics of lean/non-obese (L/NO) nonalcoholic fatty liver disease (NAFLD) in China.

METHODS

The databses, inlcuding PubMed, Web of Science, EMBASE, as well as Cochrane databases, were retrieved for eligible studies. The prevalence together with clinical features of L/NO-NAFLD in China were analyzed using a random/fixed effects model. Lean or nonobese participants were characterized by the cut-offs of body mass index used in original studies. Heterogeneity was identified using meta-regression and subgroup analyses.

RESULTS

We included 25 studies for the final analysis comprising 229091 L/NO Chinese adults and 22641 diagnosed with NAFLD, with the NAFLD prevalence of 8.98% (95% confidence interval [CI]: [5.55-13.13] for L-NAFLD Chinese participants and 13.77% (95% CI: [11.13-16.63]) for NO-NAFLD Chinese participants. This prevalence gradually increased during the past few years. The community and health checkup populations presented similar prevalence (14.19% vs. 13.55%). Meanwhile, L/NO patients with NAFLD showed lower blood pressure (128.86/80.48 vs. 136.09/84.98 mmHg), waist circumference (80.63 vs. 92.73 cm), fasting blood glucose (5.53 vs. 5.69 mmol/L), uric acid (339.14 vs. 365.46 μmol/L), triglyceride levels (1.63 vs. 1.94 mmol/L), alanine transaminase (30.28 vs. 33.12 IU/L), and γ-glutamyl transferase (29.9 vs. 43.68 IU/L), but higher levels of high-density lipoprotein cholesterol (1.33 vs. 1.26 mmol/L) compared to overweight/obese (OW/O) patients with NAFLD.

CONCLUSION

Prevalence of NAFLD was slightly lower among the L/NO-NAFLD Chinese population than the global level but has obviously increased recently. In addition, the metabolic profile of L/NO-NAFLD patients was generally better compared to OW/O-NAFLD patients.PROSPERO Reg. No.: CRD42022327240.

Analysis of clinical findings and serum micronutrients in pediatric patients with nonalcoholic fatty liver disease

Aim: Serum micronutrient levels play an important role in liver metabolism. This study examines risk factors and diagnostic methods for patients on follow-up due to nonalcoholic fatty liver disease (NAFLD). NAFLD and the control groups were compared for clinical findings, serum ferritin, B12, and vitamin D levels, and their relationship with NAFLD was examined. Material and Method: Included in the study were 60 NAFLD patients and 66 other children that formed the control group. The two groups were compared in serum lipid profile, aminotransferase, insulin, glucose, and HOMA-IR. Ultrasonography (USG) and Shear wave elastography (SWE) were performed on all patients. Both groups were then analyzed in terms of serum ferritin, B12, and vitamin D levels. Results: NAFLD and control groups were compared in terms of USG and SWE results. 35% (n=21)of the patients in the NAFLD group had grade 1, 55% (n=33) had grade 2 and 10% (n=6) had grade 3 adiposity. HOMA-IR and insulin levels were higher in the NAFLD group (p=0.02; p=0.001). While the serum ferritin level of the patients in the NAFLD group was higher than the control group (p=0.001); the B12 level was lower (p=0.006). In terms of vitamin D, there was no difference (p=0.368). Conclusion: It is essential to identify risk factors in children on follow-up due to NAFLD. USG and liver function tests remain the first option in the diagnosis and screening of NAFLD in children. Serum ferritin, B12, and vitamin D levels of children on follow-up due to NAFLD should be analyzed in consideration of liver fattening.

Vitamin D improves hepatic steatosis in NAFLD via regulation of fatty acid uptake and β-oxidation

INTRODUCTION

The study aimed to explore the association of serum 25(OH)D₃ and hepatic steatosis in non-alcoholic fatty liver disease (NAFLD) patients and to determine whether the effect of vitamin D (VD) is mediated by activation of the peroxisome proliferator-activated receptor α (PPARα) pathway.

METHODS

The study contained a case-control study, in vivo and in vitro experiments. A case-control study was conducted to compare serum parameters between NAFLD patients and controls and to evaluate the association of 25(OH)D₃ and NAFLD. In vivo study, male Wistar rats were randomly divided into control and model groups, fed a standard chow diet and a high-fat diet (HFD), respectively, for 7 weeks to generate an NAFLD model. Then, the rats were treated with VD and a PPARα antagonist (MK886) for 7 weeks. Tissue and serum were collected and assessed by biochemical assays, morphological analysis, histological analysis, and western blot analysis. In vitro, HepG2 cells were incubated with oleic acid (OA) to induce steatosis, which was evaluated by staining. HepG2 cells were pretreated with MK886 followed by calcitriol treatment, and differences in lipid metabolism-related proteins were detected by western blot.

RESULTS

NAFLD patients were characterized by impaired liver function, dyslipidemia, and insulin resistance. Serum 25(OH)D₃ was negatively associated with alanine aminotransferase (ALT) in NAFLD. VD deficiency was a risk factor for patients with no advanced fibrosis. Adequate VD status (25(OH)D₃ >20 ng/mL) had a protective effect in patients after adjustment for confounding variables. NAFLD rats showed hyperlipidemia with severe hepatic steatosis, systematic inflammation, and lower serum 25(OH)D₃. VD treatment ameliorated hepatic steatosis both in NAFLD rats and OA-induced HepG2 cells. Further, MK886 inhibited the anti-steatosis effect of VD.

CONCLUSION

The study revealed that an adequate VD level may act as a protective factor in NAFLD and that VD may alleviate hepatic steatosis via the PPARα signaling pathway.

Association Between Serum Afamin Levels with Nonalcoholic Associated Fatty Liver Disease

Afamin is a member of the hepatokine that are strongly associated with various metabolic diseases. The relationship between afamin and nonalcoholic fatty liver disease (NAFLD) remains unclear. This study aimed to explore the correlation between serum afamin levels and NAFLD. We analyzed 88 NAFLD patients and 88 age- and sex-matched healthy controls who took their health examinations at the First Affiliated Hospital, Zhejiang University School of Medicine. The association was further confirmed in 22 biopsy-confirmed NAFLD patients and 36 healthy controls. Serum afamin levels were evaluated using an enzyme-linked immunosorbent assay (ELISA). NAFLD patients had significantly higher serum afamin levels than the healthy controls (14.79 ± 5.04 mg/L versus 10.83 ± 3.24 mg/L; P < 0.001). Serum afamin levels were positively correlated with metabolic parameters including the body mass index, waist circumference, systolic blood pressure, liver enzymes, and lipid profiles. A multiple regression analysis showed that serum afamin levels were independently related to the risk of NAFLD (OR: 1.289, 95% CI, 1.141-1.456; P < 0.001). The receiver operating characteristic (ROC) analysis showed that the area under curve (AUC) of serum afamin plus the BMI for detecting NAFLD was 0.878. In participants with liver biopsies, the serum afamin plus the BMI detected NAFLD with an AUC of 0.758. In conclusion, serum afamin levels were positively associated with prevalence and risk of NAFLD, and serum afamin plus the BMI had a high diagnostic performance for NAFLD. This study provides epidemiological evidence of afamin in NAFLD.

The Association Between Vitamin D and Type 2 Diabetes Mellitus Complicated with Non-Alcoholic Fatty Liver Disease: An Observational Cross-Sectional Study

OBJECTIVE

To investigate the association between vitamin D deficiency and NAFLD risk in patients with type 2 diabetes mellitus (T2DM).

METHODS

Overall, 434 patients with T2DM admitted to Hebei General Hospital from January 2019 to December 2019 were selected as the study subjects. According to abdominal ultrasound findings, patients were divided into the NAFLD group and the non-NAFLD group. Participants were divided into two study groups according to the 25-hydroxyvitamin D [25(OH)D] level. 25(OH)D deficiency was defined if 25(OH)D vitamin levels were <20 ng/mL. Chi-square test and one-way analysis of variance were used to compare groups. The relationship between 25(OH)D and NAFLD risk was analyzed using correlation and regression analyses. Furthermore, subgroup analyses were performed to verify the robustness of the results.

RESULTS

The 25(OH)D level in patients with T2DM complicated by NAFLD was significantly lower than in patients with T2DM only. Vitamin D deficiency was highly prevalent among T2DM patients with NAFLD. This study suggested that vitamin D deficiency was an independent factor for developing NAFLD in patients with T2DM. T2DM patients with vitamin D deficiency had 2.045 times higher risk of developing NAFLD than those without vitamin D deficiency. Vitamin D deficiency was associated with high NAFLD preference in T2DM patients with BMI >23kg/m², but not those with BMI ≤23kg/m². The significant correlation between vitamin D deficiency and NAFLD was found in participants with BMI >23kg/m², age ≤65 years, without hypertension, TG <1.7mmol/l, HDL ≥1 mmol/l in men, ≥1.3 mmol/l in women, HBA1C ≤7%, or females.

CONCLUSION

This study suggests that T2DM people with BMI >23kg/m² were more susceptible to NAFLD by vitamin D deficiency and that it is necessary to maintain optimal serum vitamin D levels in this population.