Role of micronutrients in staging of nonalcoholic fatty liver disease: A retrospective cross-sectional study

Supplementation of Micro- and Macronutrients-A Role of Nutritional Status in Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a condition in which the pathological cumulation of fat with coexisting inflammation and damage of hepatic cells leads to progressive dysfunctions of the liver. Except for the commonly well-known major causes of NAFLD such as obesity, dyslipidemia, insulin resistance, or diabetes, an unbalanced diet and imbalanced nutritional status should also be taken into consideration. In this narrative review, we summarized the current knowledge regarding the micro- and macronutrient status of patients suffering from NAFLD considering various diets and supplementation of chosen supplements. We aimed to summarize the knowledge indicating which nutritional impairments may be associated with the onset and progression of NAFLD at the same time evaluating the potential therapy targets that could facilitate the healing process. Except for the above-mentioned objectives, one of the most important aspects of this review was to highlight the possible strategies for taking care of NAFLD patients taking into account the challenges and opportunities associated with the micronutrient status of the patients. The current research indicates that a supplementation of chosen vitamins (e.g., vitamin A, B complex, C, or D) as well as chosen elements such as zinc may alleviate the symptoms of NAFLD. However, there is still a lack of sufficient data regarding healthy ranges of dosages; thus, further research is of high importance in this matter.

Association of whole blood copper, zinc, calcium, magnesium, and iron with non-alcoholic fatty liver disease in overweight and obese children

OBJECTIVES

Non-alcoholic fatty liver disease (NAFLD) is a common metabolic disorder in overweight and obese children, and its etiology and pathogenesis remain unclear, lacking effective preventive and therapeutic measures. This study aims to explore the association between whole blood copper, zinc, calcium, magnesium and iron levels and NAFLD in overweight and obese children aged 6 to 17 years, providing a scientific basis for the prevention and intervention of early NAFLD in overweight and obese children.

METHODS

A cross-sectional study design was used to collect relevant data from overweight and obese children who visited the Hunan Children's Hospital from January 2019 to December 2021 through questionnaire surveys. Fasting blood samples were collected from the subjects, and various indicators such as blood glucose, blood lipid, and mineral elements were detected. All children were divided into an overweight group (n=400) and a NAFLD group (n=202). The NAFLD group was divided into 2 subgroups according to the ALT level: A non-alcoholic fatty liver (NAFL) group and a non-alcoholic steatohepatitis (NASH) group. Logistic regression analysis was used to analyze the association between minerals (copper, zinc, calcium, magnesium, and iron) and NAFLD, NAFL and NASH.

RESULTS

A total of 602 subjects were included, of whom 73.6% were male, with a median age of 10 (9, 11) years, and a body mass index (BMI) of 24.9 (22.7, 27.4) kg/m2. The intergroup comparison results showed that compared with the overweight group, the NAFLD group had higher levels of age, BMI, diastolic blood pressure (DBP), systolic blood pressure (SBP), triglyceride (TG), low density lipoprotein (LDL), alanine transaminase (ALT) and aspartate aminotransferase (AST), and lower level of high density lipoprotein (HDL). The NAFL group had higher levels of age, BMI, DBP, SBP, ALT, and AST, and lower levels of HDL compared with the overweight group. The levels of age, BMI, DBP, SBP, TG, LDL, ALT, and AST of NASH were higher than those in the overweight group, while the level of HDL was lower than that in overweight group (all P<0.017). After adjusting for a variety of confounders, the OR of NAFLD for the highest quantile of iron was 1.79 (95% CI 1.07 to 3.00) compared to the lowest quantile, and no significant association was observed between copper, zinc, calcium, and magnesium, and NAFLD. The subgroup analysis of NAFLD showed that the OR for the highest quantile of iron in children with NAFL was 2.21 (95% CI 1.26 to 3.88), while no significant association was observed between iron level and NASH. In addition, no significant associations were observed between copper, zinc, calcium, and magnesium levels and NAFL or NASH.

CONCLUSIONS

High iron level increases the risk of NAFLD (more likely NAFL) in overweight and obese children, while copper, zinc, calcium, magnesium, and other elements are not associated with the risk of NAFLD in overweight and obese children.

Genetically determined circulating micronutrients and the risk of nonalcoholic fatty liver disease

Evidence from epidemiological literature on the association of circulating micronutrients with risk of nonalcoholic fatty liver disease (NAFLD) is inconsistent. We aimed to elucidate the causal relationships using Mendelian randomization (MR). Single-nucleotide polymorphisms associated with 14 circulating micronutrients (β-carotene, calcium, copper, folate, iron, magnesium, phosphorus, selenium, vitamin B6, B12, C, D, K1 and zinc) were employed as instrumental variables. Summary level data for NAFLD were obtained from a genome-wide association study (GWAS) meta-analysis of 8434 cases and 770,180 controls (discovery stage) and another two datasets including 1483 NAFLD cases and 17,781 controls (replication stage 1) and 2134 NAFLD cases and 33,433 controls (replication stage 2). Inverse variance-weighted method (IVW) was used as primary analysis, supplemented with a series of sensitivity analysis. Genetically predicted higher β‑carotene levels were suggestively associated with reduced NAFLD risk [odds ratio (OR) 0.81, 95% confidence interval (CI) 0.66-0.99; P = 0.047], whereas the association did not survive the false discovery rates (FDR) correction (PFDR = 0.164). Genetically predicted circulating iron (OR 1.16, 95% CI 1.05-1.29; P = 0.006, PFDR = 0.028), selenium (OR 1.11, 95% CI 1.03-1.20; P = 0.005, PFDR = 0.028) and vitamin B12 (OR 1.08, 95% CI 1.03-1.13; P = 0.002, PFDR = 0.028) were significantly associated with increased risk of NAFLD. Moreover, the findings were consistent in individual datasets (Pheterogeneity > 0.05) and confirmed in sensitivity analysis. Our study provided evidence that circulating iron, selenium and vitamin B12 might be causally linked to the risk of NAFLD, which deserves further exploration of the potential biological mechanism.

Bi-directional causal effect between vitamin B12 and non-alcoholic fatty liver disease: Inferring from large population data

Objectives

Many observational studies evaluate the association between vitamin B12 and non-alcoholic fatty liver disease (NAFLD). However, the causality of this association remains uncertain, especially in European populations. We conducted a bidirectional Mendelian randomization study to explore the association between vitamin B12 and NAFLD.

Methods

Two-sample Mendelian randomization study was conducted. Summary statistics for vitamin B12 were acquired from a genome-wide association studies (GWAS) meta-analysis including 45,576 subjects. Summary-level data for NAFLD was obtained from a GWAS meta-analysis of 8,434 cases and 770,180 non-cases and another GWAS meta-analysis of 1,483 cases and 17,781 non-cases. Summary-level data for 4 enzymes including alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma glutamyltransferase (GGT), was available from the UK Biobank. Inverse variance weighting (as main analysis), weighted median estimate, robust adjusted profile score, MR-Egger, and MR-PRESSO (sensitivity analyses) were performed to calculate causal estimates.

Results

Genetically predicted higher vitamin B12 concentrations were consistently associated with an increased NAFLD in two sources. The combined odds ratio (OR) of NAFLD was 1.30 (95% confidence interval (CI), 1.13 to 1.48; p < 0.001) per SD-increase in vitamin B12 concentrations. Genetic liability to NAFLD was also positively associated with vitamin B12 concentrations (Beta 0.08, 95%CI, 0.01 to 0.16; p = 0.034). Sensitivity analyses also revealed consistent results. Genetically predicted vitamin B12 concentrations showed no significant association with liver enzymes.

Conclusion

The present study indicates that increased serum vitamin B12 concentrations may play a role in NAFLD risk. NAFLD also has a causal impact on elevated vitamin B12 concentrations in the circulation. Notably, vitamin B12 concentrations imply the levels of vitamin B12 in the circulation, and higher intake of vitamin B12 may not directly lead to higher levels of serum vitamin B12, instead the higher levels of vitamin B12 in the circulation may be caused by the dysregulation of the metabolism of this vitamin in this study. There exist bidirectional causal effects between serum vitamin B12 concentrations and risk of NAFLD in European individuals.

Non-alcoholic fatty liver disease prevalence in Latin America: A systematic review and meta-analysis

Non-alcoholic fatty liver disease (NAFLD) produces high morbidity and mortality rates. Its worldwide prevalence is 25%, but evidence from Latin America (LA) is lacking. We aimed to estimate the prevalence of NAFLD in the adult population of LA. We conducted a systematic review and meta-analysis. Data were collected from OVID, Cochrane Library and LILACS search engines. We used terms related to NAFLD and LA countries. Observational studies in adults who were born and live in LA were included. Two reviewers evaluated the articles, extracted data and assessed the risk of bias. Discrepancies were resolved by consensus or by a third reviewer. A validated tool was used to assess risk of bias. We found and analyzed 19 articles (n=5625). The prevalence in the general and captive population found was 24%. Populations with type 2 diabetes mellitus or obesity had a higher mean prevalence that reached 68%. We concluded that the average prevalence of NAFLD in LA is around 24%. Among high-risk groups, this value increases to 68%. Further studies in the general population using appropriate designs are required for an accurate estimate of the prevalence of NAFLD in LA.

Clinical Relevance of Vitamins and Carotenoids With Liver Steatosis and Fibrosis Detected by Transient Elastography in Adults

Background: Vitamins and carotenoids may be involved in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Previously related publications mainly focused on vitamin D and vitamin E, and studies on other vitamins and carotenoids and NAFLD are scarce. Methods: This study aimed to explore the clinical relevance of vitamin A, B vitamins (vitamin B1, vitamin B2, niacin, vitamin B6, folate, vitamin B12, and choline), vitamin C and carotenoids (α-carotene, β-carotene, β-cryptoxanthin, lycopene, lutein + zeaxanthin) with liver steatosis and fibrosis in the 2017-2018 NHANES (N = 4,352). Liver steatosis and fibrosis were detected by transient elastography. Logistic regression, linear regression and restricted cubic splines were adopted to explore the non-linear dose-response relationships. Results: Higher intakes of vitamin C [0.68 (0.50-0.93)] and β-carotene [0.71 (0.54-0.93)] were inversely associated with liver steatosis. Higher levels of serum vitamin C [0.45 (0.32-0.62)] were inversely associated with liver fibrosis, while higher intakes of choline [1.43 (1.04-1.98)] and α-carotene [1.67 (1.01-2.74)] were positively associated with liver fibrosis. In addition, marginally inverse association between lutein + zeaxanthin and liver steatosis and positive association between vitamin B12 and liver fibrosis were found. In linear regression, the above-mentioned associations between vitamin C, β-carotene, and lutein + zeaxanthin and liver steatosis, and serum vitamin C, choline, α-carotene, and vitamin B12 and liver fibrosis were also found. The above-mentioned associations were mainly linear, while the relationship between β-carotene and liver steatosis might be non-linear. Conclusion: Vitamin C, α-carotene, β-carotene, lutein + zeaxanthin, choline and vitamin B12 may be associated with liver steatosis and fibrosis.

The role of zinc in the prevention and treatment of nonalcoholic fatty liver disease

The zinc element is an essential nutrient for human health. Zinc is involved in the glucose, lipid, and protein metabolism and antioxidant processes in biological pathways. Zinc deficiency can lead to several chronic liver diseases. Nonalcoholic fatty liver disease (NAFLD) is one of the most common liver diseases where zinc deficiency plays a critical role in pathogenesis. Human and animal studies showed that both NAFLD risk factors (i.e., insulin resistance, diabetes mellitus, dyslipidemia, obesity, hypertension) and NAFLD itself are associated with decreased blood levels of zinc. Additionally, endoplasmic reticulum stress and inflammation due to unfolded protein response, inadequate dietary zinc intake, and decreased zinc absorption from the gastrointestinal tract can result in zinc deficiency leading to NAFLD. Herein, we reviewed the mechanistic links between zinc deficiency and NAFLD development and the role of zinc in the prevention and treatment of NAFLD.

Serum iron and risk of nonalcoholic fatty liver disease and advanced hepatic fibrosis in US adults

Epidemiological evidence on the relationship between serum iron and liver diseases is limited. This study aims to investigate whether serum iron is associated with nonalcoholic fatty liver disease (NAFLD) and advanced hepatic fibrosis (AHF). Cross-sectional data for adults aged ≥ 18 years who participated in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018 were analyzed. Odds ratio (ORs) and 95% confidence intervals (CIs) of NAFLD and AHF associated with serum iron were estimated using multivariable logistic regression models. A total of 18,031 males and 18,989 females were included in the analysis. After multivariable adjustment for potential confounders, serum iron was significantly and inversely associated with NAFLD in both genders (P-trend < 0.001) and AHF in females (P-trend = 0.018). Compared to the bottom quartile, those in higher quartiles of serum iron had no significant ORs for AHF in males, but the trend across the quartiles was significant (P-trend = 0.046). In conclusion, higher serum iron level was associated with lower risk of NAFLD in males and females, and with lower risk of AHF in females but not in males. No significant racial/ethnical differences in these associations were observed.