Mediterranean dietary pattern and non-alcoholic fatty liver diseases: a case-control study

Association between Dietary Quality and Non-Alcoholic Fatty Liver Disease in Korean Adults: A Nationwide, Population-Based Study Using the Korean Healthy Eating Index (2013-2021)

This study explored the relationship between the Korean Healthy Eating Index (KHEI) and non-alcoholic fatty liver disease (NAFLD). This cross-sectional study included 34,174 Korean adults. The KHEI was composed of three subcomponents (adequacy, moderation, and energy balance) and calculated based on a 24 h dietary recall. The total score ranged from 0 to 100, with a higher score indicating a greater adherence to the Korean dietary guidelines. The total KHEI scores were categorized into quartiles (Q1-Q4). NAFLD was classified using the hepatic steatosis index. Logistic regressions were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). The adjusted OR (95% CI) of NAFLD was 0.95 (0.87-1.03) for the Q2 group, 0.90 (0.83-0.98) for the Q3 group, and 0.79 (0.72-0.87) for the Q4 group, compared with the Q1 group. Among the subcomponents of the KHEI, individuals with high scores in the adequacy component, characterized by an abundant consumption of fruits, vegetables, and dairy products, exhibited the most pronounced association with NAFLD. A higher KHEI score was negatively associated with NAFLD in Korean adults. Therefore, the promotion of healthy dietary patterns can play a beneficial role in the prevention or management of NAFLD.

Association between Baltic sea diet and healthy Nordic diet index with risk of non-alcoholic fatty liver disease: a case-control study

Recent evidence shows the beneficial effects of Baltic Sea diet score (BSDS) and healthy Nordic diet index (HNDI) on chronic diseases, however, there is no evidence to investigate them on the risk of non-alcoholic fatty liver disease (NAFLD). The purpose of this study was to investigate the associations between BSDS and HNDI with the risk of NAFLD. In this case-control study, 552 people in good health and 340 people with NAFLD over the age of 18 took part. The evaluation of BSDS and HNDI employed a validated 168-item semi-quantitative food frequency questionnaire (FFQ). Binary logistic regression was used to determine how OBS and NAFLD are related. The mean BSDS and HNDI were 16.00 ± 2.49 and 11.99 ± 2.61, respectively. The final model's confounder adjustment revealed that greater HNDI adherence scores gave protection against the occurrence of NAFLD (odds ratio [OR]: 0.42; 95% confidence interval [CI] 0.18-0.98; P for trend = 0.043). In addition, those with the highest BSDS scores had significantly lower risks of developing NAFLD compared to subjects with the lowest scores (OR = 0.48, 95% CI 0.32-0.89; p for trend = 0.003). Our findings showed that following a healthy Nordic diet can significantly prevent the risk of developing NAFLD, and suggest that the highly nutritious components of the Nordic diet are beneficial for the prevention of NAFLD.

Adherence to a Traditional Mexican Diet Is Associated with Lower Hepatic Steatosis in US-Born Hispanics of Mexican Descent with Overweight or Obesity

Hispanics of Mexican descent have disproportionate rates of non-alcoholic fatty liver disease (NAFLD). The purpose of this work is to investigate the association between the traditional Mexican diet score (tMexS) and hepatic steatosis and fibrosis, two NAFLD-related clinical endpoints, in Hispanic adults of Mexican descent. Data from 280 Hispanic adults of Mexican descent (n = 102 men, 178 women) with overweight or obesity enrolled in a cross-sectional observational study were analyzed. The tMexS was calculated from 24 h dietary recalls. Hepatic steatosis and fibrosis measurements were assessed using transient elastography (Fibroscan®). Linear regression models testing the association between tMexS and hepatic steatosis and fibrosis were run individually and through the stratification of significant modifiers. Mean tMexS were 5.9 ± 2.1, hepatic steatosis scores were 288.9 ± 48.9 dB/m, and fibrosis scores were 5.6 ± 2.2 kPa. Among the US-born group, with every point increase in the tMexS, there was a statistically significant 5.7 lower hepatic steatosis point (95% CI: -10.9, -0.6, p-value = 0.07). Higher adherence to a traditional Mexican diet was associated with lower hepatic steatosis in US-born Hispanics of Mexican descent. Findings from the current work may serve to inform future culturally relevant interventions for NAFLD prevention and management in individuals of Mexican descent.

Fatty acid composition but not quantity is an important indicator of non-alcoholic fatty liver disease: a systematic review

BACKGROUND

There is still paucity on the effects of dietary and supplemental fatty acid on non-alcoholic fatty liver disease (NAFLD). The aim of this review is to systematically review and summarise the effect of fatty acids intake on liver-related outcomes in adult patients with NAFLD.

METHODS

The review was conducted using Cochrane CENTRAL Library, Scopus, Embase, MEDLINE, PubMed, and Web of Science. A total of 2786 records were identified, and of these, 36 studies (31 were randomised control trials (RCTs), and 5 were case-control studies) were included. Quality assessment was conducted using the Revised Cochrane Risk of Bias tool and Joanna Briggs Institute checklists.

RESULTS

Of 36 articles, 79% of RCTs and 66% of case-control studies had a low risk of bias. Potential heterogeneity has been observed in assessment of liver-related outcomes. According to the RCTs, there was moderate evidence (3/6 studies) that a diet characterised by a high MUFA, PUFA and low SFA showed reduced liver fat and stiffness. The using of culinary fats that are high in MUFA (4/6 studies) reduces liver steatosis. n-3 PUFA supplementation in combination with a hypocaloric or heart healthy diet with a low SFA improved liver enzyme level (5/14 studies) and steatosis score (3/14 studies).

CONCLUSIONS

Effects on NAFLD parameters, including liver fat content (assessed via magnetic resonance imaging/spectroscopy), stiffness and steatosis score (assessed by ultrasonography), were primarily related to fatty acid composition independent of energy intake. Further investigation is needed to determine the mechanism of specific fatty acid on the accumulation of liver fat.

Risk Factors of Non-alcoholic Fatty Liver Disease in the Iranian Adult Population: A Systematic Review and Meta-analysis

Context: Non-alcoholic fatty liver disease (NAFLD) is progressing considerably worldwide. Identifying the risk factors of NAFLD is a critical step in preventing its progression. Methods: In November 2022, two independent researchers studied seven databases, including PubMed, ISI/WoS, ProQuest, Scopus, SID, Magiran, and Google Scholar, and reference list of relevant articles, searching studies that assessed NAFLD risk factors in the Iranian adult population. Heterogeneity between studies was assessed by Cochran’s test and its composition using I2 statistics. A random-effects model was used when heterogeneity was observed; otherwise, a fixed-effects model was applied. Egger’s regression test and Trim-and-Fill analysis were used to assess publication bias. Comprehensive Meta-analysis software (version 3) was used for the analyses of the present study. Results: The results of this study showed significant associations between NAFLD with age (n = 15, odds ratio (OR) = 2.12, 95% CI: 1.79 - 2.51), body mass index (n = 46, OR = 5.00, 95% CI: 3.34 - 7.49), waist circumference (n = 20, OR = 6.37, 95% CI: 3.25 - 12.48), waist-to-hip ratio (n = 17, OR = 4.72, 95% CI: 3.93 - 5.66), total cholesterol (n = 39, OR = 1.80, 95% CI: 1.52 - 2.13), high-density lipoprotein (n = 37, OR = 0.53, 95% CI: 0.44 - 0.65), low-density lipoprotein (n = 31, OR = 1.68, 95% CI: 1.38 - 2.05), triglyceride (n = 31, OR = 3.21, 95% CI: 2.67 - 3.87), alanine aminotransferase (n = 26, OR = 4.06, 95% CI: 2.94 - 5.62), aspartate aminotransferase (n = 27, OR = 2.16, 95% CI: 1.50 - 3.12), hypertension (n = 13, OR = 2.53, 95% CI: 2.32 - 2.77), systolic blood pressure (n = 13, OR = 1.83, 95% CI: 1.53 - 2.18), diastolic blood pressure (n = 14, OR = 1.80, 95% CI: 1.48 - 2.20), fasting blood sugar (n = 31, OR = 2.91, 95% CI: 2.11- 4.01), homeostatic model assessment for insulin resistance (n = 5, OR = 1.92, 95% CI: 1.48 - 2.59), diabetes mellitus (n = 15, OR = 3.04, 95% CI: 2.46 - 3.75), metabolic syndrome (n = 10, OR = 3.56, 95% CI: 2.79 - 4.55), and physical activity (n = 11, OR = 0.32, 95% CI: 0.24 - 0.43) (P < 0.05). Conclusions: In conclusion, several factors are significantly associated with NAFLD. However, anthropometric indices had the strongest relationship with NAFLD in the Iranian adult population.

Decreased autophagosome biogenesis, reduced NRF2, and enhanced ferroptotic cell death are underlying molecular mechanisms of non-alcoholic fatty liver disease

BACKGROUND AND AIMS

Caloric excess and sedentary lifestyles have led to an epidemic of obesity, metabolic syndrome, and non-alcoholic fatty liver disease (NAFLD). The objective of this study was to investigate the mechanisms underlying high fat diet (HFD)-induced NAFLD, and to explore NRF2 activation as a strategy to alleviate NAFLD.

APPROACH AND RESULTS

Herein, we demonstrated that high fat diet (HFD) induced lipid peroxidation and ferroptosis, both of which could be alleviated by NRF2 upregulation. Mechanistically, HFD suppressed autophagosome biogenesis through AMPK- and AKT-mediated mTOR activation and decreased ATG7, resulting in KEAP1 stabilization and decreased NRF2 levels in mouse liver. Furthermore, ATG7 is required for HFD-induced NRF2 downregulation, as ATG7 deletion in Cre-inducible ATG7 knockout mice decreased NRF2 levels and enhanced ferroptosis, which was not further exacerbated by HFD. This finding was recapitulated in mouse hepatocytes, which showed a similar phenotype upon treatment with saturated fatty acids (SFAs) but not monounsaturated fatty acids (MUFAs). Finally, NRF2 activation blocked fatty acid (FA)-mediated NRF2 downregulation, lipid peroxidation, and ferroptosis. Importantly, the HFD-induced alterations were also observed in human fatty liver tissue samples.

CONCLUSIONS

HFD-mediated autophagy inhibition, NRF2 suppression, and ferroptosis promotion are important molecular mechanisms of obesity-driven metabolic diseases. NRF2 activation counteracts HFD-mediated NRF2 suppression and ferroptotic cell death. In addition, SFA vs. MUFA regulation of NRF2 may underlie their harmful vs. beneficial effects. Our study reveals NRF2 as a key player in the development and progression of fatty liver disease and that NRF2 activation could serve as a potential therapeutic strategy.

Relationship between the Mediterranean diet and risk of hepatic fibrosis in patients with non-alcoholic fatty liver disease: A cross-sectional analysis of the RaNCD cohort

Background

Despite evidence supporting the beneficial effects of the Mediterranean diet (MedDiet) on hepatic steatosis in subjects with non-alcoholic fatty liver disease (NAFLD), the relationship of the MedDiet with hepatic fibrosis is as yet unclear. The aim of the present study was to explore this association in Iranian adults with NAFLD.

Methods

This cross-sectional study included 3,325 subjects with NAFLD from the Ravansar Noncommunicable Disease (RaNCD) cohort. Dietary intake data were collected by a validated food frequency questionnaire (FFQ). The MedDiet score was computed based on a nine-point scale constructed by Trichopoulou et al. Fatty liver index (FLI) and fibrosis-4 (FIB-4) index were used to predict hepatic steatosis and fibrosis in the population. Multivariate regression models were applied to determine associations.

Results

Subjects in the highest tertile of MedDiet score had a higher platelet and a lower weight, total cholesterol (TC), LDL-c, and FLI than those in the lowest tertile (p-value < 0.05). Adherence to the MedDiet was associated with a 7.48 (95%CI: 5.376 to 9.603; p-value: 0.001) × 10³/μl; -0.417 (95%CI: -0.819 to -0.014; p-value: 0.042) kg, -2.505 (95%CI: -3.835 to -1.175; p-value: 0.001) mg/dl; and -1.93 (95%CI: -2.803 to -1.061; p-value: 0.001) mg/dl change in platelet, weight, TC, and LDL-c for each SD increase in the score, respectively. A significant linear trend was observed in odds of hepatic fibrosis across the tertiles of the MedDiet score (P-trend: 0.008). This linear trend was attenuated but remained significant after the adjustment of the relevant confounders (P-trend: 0.032). Adherence to the MedDiet was independently associated with about 16% lower odds of having hepatic fibrosis in patients with NAFLD for each SD increase in the score.

Conclusion

Adherence to the MedDiet characterized by a high intake of whole grains, fruits, vegetables, legumes, nuts, and fish was associated with a lower risk of having hepatic fibrosis in patients with NAFLD. Further studies are required to elucidate the causal relationship of observed association in individuals of all ages, ethnicities, and etiologies of hepatic steatosis.

Association between Mediterranean Diet and Fatty Liver in Women with Overweight and Obesity

Obesity is a risk factor for NAFLD. However, not all people with obesity have an excessive intrahepatic fat content. Adherence to a high-quality dietary pattern may also promote liver health in obesity. A cross-sectional study of 2967 women with overweight and obesity was carried out to assess the association between a Mediterranean diet and fatty liver. All women underwent clinical examination, anthropometric measurements, blood sampling, ultrasound measurements of abdominal visceral and subcutaneous fat, and assessment of adherence to the Mediterranean diet using the 14-item MEDAS questionnaire. Fatty liver index (FLI), NAFLD fatty liver steatosis (NAFLD-FLS) and hepatic steatosis index (HSI) were calculated. In women with obesity, the MEDAS score was inversely associated with FLI (β = −0.60, 95% CI: −1.04, −0.16, p = 0.008), NAFLD-FLS (β = −0.092, 95% CI: −0.134, −0.049, p < 0.001) and HSI (β = −0.17, 95% CI: −0.30, −0.04, p = 0.011). Stronger associations were observed in premenopausal women with obesity. Mediterranean diet was inversely associated with NAFLD-FLS in women with overweight, independently of menopausal status. In conclusion, Mediterranean diet is associated with a better liver status in women with overweight and obesity. This may have a public health impact and be useful in drafting nutritional guidelines for NAFLD.

Crosstalk between dietary patterns, obesity and nonalcoholic fatty liver disease

The prevalence of nonalcoholic fatty liver disease (NAFLD) is rising worldwide, paralleling the epidemic of obesity. The liver is a key organ for the metabolism of proteins, fats and carbohydrates. Various types of fats and carbohydrates in isocaloric diets differently influence fat accumulation in the liver parenchyma. Therefore, nutrition can manage hepatic and cardiometabolic complications of NAFLD. Even moderately reduced caloric intake, which leads to a weight loss of 5%-10% of initial body weight, is effective in improving liver steatosis and surrogate markers of liver disease status. Among dietary patterns, the Mediterranean diet mostly prevents the onset of NAFLD. Furthermore, this diet is also the most recommended for the treatment of NAFLD patients. However, clinical trials based on the dietary interventions in NAFLD patients are sparse. Since there are only a few studies examining dietary interventions in clinically advanced stages of NAFLD, such as active and fibrotic steatohepatitis, the optimal diet for patients in these stages of the disease must still be determined. In this narrative review, we aimed to critically summarize the associations between different dietary patterns, obesity and prevention/risk for NAFLD, to describe specific dietary interventions' impacts on liver steatosis in adults with NAFLD and to provide an updated overview of dietary recommendations that clinicians potentially need to apply in their daily practice.