Association between processed and unprocessed red meat consumption and risk of nonalcoholic fatty liver disease: A systematic review and dose-response meta-analysis

Milpa Diet for MASLD in Mesoamerican Populations: Feasibility, Advantages, and Future Perspectives

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the leading cause of chronic liver disease, linked closely to metabolic syndrome and rising obesity rates. Affecting up to 37% of the global adult population, MASLD prevalence is exceptionally high among individuals of Hispanic descent, with genetic factors such as the PNPLA3 gene mutation playing a significant role. The subject of this review is the traditional Mesoamerican "milpa" diet, which includes unprocessed local crops like maize, beans, pumpkins, chili, and tomatoes and may represent a strategy to combat MASLD. Current treatment recommendations emphasize weight loss; a reduced intake of saturated fats, processed meats, and added sugars; and increased physical activity. The milpa diet, rich in protein, fiber, vitamins, and bioactive compounds, aligns with these recommendations and could potentially mitigate MASLD by preventing liver fat accumulation and fibrosis. This narrative review focuses on available preclinical and clinical studies adopting the milpa diet as a culturally relevant, nutritious, and sustainable dietary approach in preventing and treating MASLD. More clinical studies are needed to develop precise nutritional quantitative recommendations and guidelines.

The association between total, animal, and plant protein intake and metabolic dysfunction-associated fatty liver disease in overweight and obese children and adolescents

BACKGROUND

Dietary protein plays a crucial role in the growth and development of children and adolescents. However, recent evidence has shown inconsistent findings regarding the impact of dietary protein sources on health outcomes. This study aimed to investigate the association between total, animal, and plant protein intake and the odds of metabolic dysfunction-associated fatty liver disease (MAFLD) in overweight and obese children and adolescents.

METHODS

This cross-sectional study included 505 participants (52.9% males) aged 6-18 years, with a body mass index (BMI)-for-age z-score ≥ 1 based on WHO standards. MAFLD diagnosis followed established consensus definitions. Dietary intake of total, animal, and plant protein was assessed using a validated 147-item food frequency questionnaire. Adjusted logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for MAFLD across protein intake and subtype quartiles.

RESULTS

The participants had a mean age of 10.0 ± 2.3 years and a mean BMI-for-age z-score of 2.70 ± 1.01. Higher animal protein intake was significantly associated with an increased likelihood of MAFLD (highest vs. lowest quartile OR: 2.31; 95% CI: 1.01-5.30). Conversely, higher plant protein intake was significantly associated with reduced odds of MAFLD (highest vs. lowest quartile OR:0.48;95% CI:0.23-0.96). No significant relationship was found between total protein intake and MAFLD odds.

CONCLUSIONS

Our findings highlight the significance of dietary protein source in the odds of MAFLD among overweight and obese children and adolescents. Further studies are warranted to confirm these findings and explore the underlying mechanisms.

Meat and fish consumption, genetic risk and risk of severe metabolic-associated fatty liver disease: a prospective cohort of 487,875 individuals

BACKGROUND

Diet, specifically meat consumption, has been implicated as a modifiable risk factor in the development of metabolic-associated fatty liver disease (MAFLD). This study aimed to investigate the associations between various types of meat intake and the risk of severe MAFLD and to examine whether genetic risk influences these associations.

METHODS

This research utilized data from the UK Biobank, which initially enrolled over 500,000 participants between 2006 and 2010, of whom 487,875 were eligible for our analyses. Meat intake, including unprocessed red meat, processed meat, poultry, and fish, was evaluated through a validated touchscreen questionnaire. Cox proportional hazards models were used to analyze the relationship between meat consumption and severe MAFLD risk, adjusting for potential confounders. Genetic risk scores (GRS) were calculated using five MAFLD-associated SNPs, allowing for analyses of gene-diet interactions.

RESULTS

During a follow-up period totaling 6,036,554 person-years (mean duration: 12.1 years), 5,731 new cases of severe MAFLD were identified. High intakes of total meat, processed meat, unprocessed red meat and poultry were associated with increased MAFLD risk, with adjusted hazard ratios (HR) of 1.76 (95% CI: 1.33-2.33), 1.19 (1.02-1.40), 1.34 (1.17-1.53), and 1.21 (0.98-1.49), respectively, for the highest versus lowest intake categories. In contrast, oily fish intake showed a protective association (HR: 0.72; 95% CI: 0.53-0.97). No significant interaction was observed between meat intake and GRS for any meat subtype, suggesting that the associations were independent of genetic predisposition.

CONCLUSIONS

High consumption of red and processed meat was associated with an increased risk of severe MAFLD, while oily fish intake showed an inverse association with the risk of MAFLD. These effects were consistent across genetic risk levels for MAFLD. Our findings reinforce dietary recommendations to limit red and processed meat and encourage oily fish intake for MAFLD prevention, irrespective of individual genetic risk.

A study of correlation of the dietary index for gut microbiota with non-alcoholic fatty liver disease based on 2007-2018 National Health and Nutrition Examination Survey

Objective

To explore the correlation of dietary index for gut microbiota (DI-GM) with non-alcoholic fatty liver disease (NAFLD).

Methods

Data of 6,711 participants were extracted from the National Health and Nutrition Examination Survey (NHANES) during 2007-2018. A weighted logistic regression analysis was employed for assessment of the correlation of DI-GM with NAFLD, and a restricted cubic spline (RCS) analysis was implemented to examine potential non-linear associations. Subgroup analyses were conducted to identify particularly susceptible groups. Additionally, the synergistic effects of different DI-GM components on NAFLD risk was assessed by weighted quantile sum (WQS) regression.

Results

The DI-GM exhibited statistically significant correlation with NAFLD [OR (95%CI):0.91 (0.85, 0.98), p = 0.015]. The results of the RCS analysis indicated a linear correlation of DI-GM and NAFLD (p = 0.810 for non-linearity). Further stratified analyses indicated that the negative correlation of DI-GM with NAFLD were significant and consistent for all subgroups. The results of WQS regression revealed that soybean (27%), refined grains (17%), coffee (16%), and red meat (9%) had the highest contribution weights to NAFLD.

Conclusion

As an important tool for assessment of the influences of diet on gut microbiota, DI-GM is negatively correlated with NAFLD risk factors. Soybean, refined grains, coffee, and red meat are key factors influencing NAFLD. The direct correlation of DI-GM with NAFLD shall be explored and the effectiveness of prevention and treatment of NAFLD shall be evaluated by improving DI-GM scores via dietary interventions.

BMI gain and dietary characteristics are risk factors of MASLD in non-obese individuals

This longitudinal observational study aimed to evaluate whether cardiometabolic factors and dietary characteristics are determinants of metabolic dysfunction-associated steatotic liver disease (MASLD) in non-obese individuals (body mass index [BMI] < 25 kg/m²). The study was conducted at the Japanese Red Cross Society Kyoto Daiichi Hospital. Clinical data were longitudinally recorded at annual health checks. The diagnosis of MASLD was based on the results of abdominal ultrasonography and cardiometabolic criteria. Lifestyle behaviors and dietary characteristics were assessed using a self-administered questionnaire. A total of 4,100 non-obese middle-aged and older participants (1,636 men and 2,464 women) were followed up for an average of 6.44 ± 4.16 years. During the follow-up period, there were 410 new cases of MASLD in men (25.1%) and 484 in women (19.6%). The incidence rate was higher for men (39.7 per 1,000 person-years) than for women (30.1 per 1,000 person-years). Multivariable-adjusted logistic regression analyses using the rate of change per year with standardized values found that BMI gain was strongly associated with the onset of MASLD for both men (OR: 1.90, 95% CI: 1.64-2.19) and women (OR: 1.95, 95% CI: 1.72-2.21). Increased waist circumference and triglycerides were also associated with MASLD onset for both men and women. Lowering of high-density lipoprotein cholesterol was identified as a risk factor for MASLD in both men and women. Regarding dietary characteristics, the onset of MASLD was significantly and negatively associated with "often eating vegetables" for men (OR: 0.73, 95% CI: 0.57-0.93) and "often eating soy products" for women (OR: 0.71, 95% CI: 0.58-0.88), even after adjusting for BMI change and other covariates. These findings suggest that maintaining body weight and favorable dietary characteristics are key factors in the prevention of MASLD in non-obese individuals.

The role of dietary modification in the prevention and management of metabolic dysfunction-associated fatty liver disease: An international multidisciplinary expert consensus

Metabolic dysfunction-associated fatty liver disease (MAFLD) or metabolic dysfunction-associated steatotic liver disease (MASLD), has become the leading cause of chronic liver disease worldwide. Optimal dietary intervention strategies for MAFLD are not standardized. This study aimed to achieve consensus on prevention of MAFLD through dietary modification. A multidisciplinary panel of 55 international experts, including specialists in hepatology, gastroenterology, dietetics, endocrinology and other medical specialties from six continents collaborated in a Delphi-based consensus development process. The consensus statements covered aspects ranging from epidemiology to mechanisms, management, and dietary recommendations for MAFLD. The recommended dietary strategies emphasize adherence to a balanced diet with controlled energy intake and personalized nutritional interventions, such as calorie restriction, high-protein, or low-carbohydrate diets. Specific dietary advice encouraged increasing the consumption of whole grains, plant-based proteins, fish, seafood, low-fat or fat-free dairy products, liquid plant oils, and deeply colored fruits and vegetables. Concurrently, it advised reducing the intake of red and processed meats, saturated and trans fats, ultra-processed foods, added sugars, and alcohol. Additionally, maintaining the Mediterranean or DASH diet, minimizing sedentary behavior, and engaging in regular physical activity are recommended. These consensus statements lay the foundation for customized dietary guidelines and proposing avenues for further research on nutrition and MAFLD.

Association of ultra-processed food intake with severe non-alcoholic fatty liver disease: a prospective study of 143073 UK Biobank participants

BACKGROUND

Previous studies indicate a link between non-alcoholic fatty liver disease (NAFLD) and unhealthy dietary patterns or nutrient intake. However, it remains unclear whether ultra-processed foods (UPF) contribute to an increased risk of NAFLD. This study aimed to explore how ultra-processed food consumption correlates with severe NAFLD using the UK Biobank data.

METHODS

This prospective cohort study included 143,073 participants from the UK Biobank. UPF consumption levels were determined using the NOVA classification and quantified from 24-h dietary recall data. The association between UPF consumption and severe NAFLD (hospitalization or death) was initially examined using Cox proportional hazards models with intake quartiles. Nonlinear associations were investigated using penalized cubic splines fitted in the Cox proportional hazards models. Adjustments were made for general characteristics, sociodemographic factors, body mass index (BMI), and lifestyle.

RESULTS

Throughout the median follow-up period of 10.5 years, 1,445 participants developed severe NAFLD. The adjusted models indicated a significant increase in severe NAFLD risk in higher UPF intake groups compared to the lowest quartile (HR: 1.26 [95% CI: 1.11-1.43]). Subgroup analysis revealed that individuals with a BMI of 25 or higher were at greater risk in the highest quartile of UPF consumption. Sensitivity analyses yielded results consistent with these findings.

CONCLUSION

Higher consumption of UPF is associated with an increased risk of severe NAFLD. Reducing the intake of UPF can be a potential approach to lower the risk of NAFLD.