The impact of dietary interventions on liver health biomarkers in individuals with metabolic dysfunction-associated steatotic liver disease (MASLD): a systematic literature review and meta-analysis of randomized controlled trials

Metabolic dysfunction-associated steatotic liver disease (MASLD) and its subtype, metabolic dysfunction-associated alcohol-related liver disease (MetALD), represent the most prevalent chronic liver diseases worldwide, closely linked to unhealthy dietary patterns. Lifestyle modification is considered first-line treatment, yet the comparative effectiveness of different dietary approaches remains unclear. This systematic review and meta-analysis aimed to evaluate the impact of dietary interventions on liver health biomarkers in individuals with MASLD and MetALD. A systematic database search was conducted for randomised controlled trials (RCTs, 2018–2024). Eligible trials assessed dietary interventions in MASLD or MetALD and reported changes in alanine aminotransferase (ALT), liver stiffness, MRI-proton density fat fraction (MRI-PDFF), and controlled attenuation parameter. Data were synthesized using weighted mean differences with fixed or random effects models. Sixty-eight full-text articles were included in the systematic review, of which 24 met the criteria for the meta-analysis. Since no eligible studies were identified in individuals with MetALD, the findings apply solely to people with MASLD. In studies on fasting interventions ALT (MD = − 12.47 IU/L; 95% CI − 22.03,− 2.92; p = 0.01; n = 6) and liver stiffness (MD = − 0.24 kPa; 95% CI − 0.46, − 0.03; p = 0.03; n = 4) were reduced compared to controls. The Mediterranean diet (MedDiet) resulted in significant differences in ALT (MD = − 2.93 IU/L; 95% CI − 5.68, − 0.19; p = 0.04; n = 9), liver stiffness (MD = − 0.35 kPa; 95% CI − 0.54, − 0.16; p = 0.00; n = 4), and MRI-PDFF (MD = − 1.37%; 95% CI − 2.33, − 0.40; p = 0.01; n = 5). LCHF/ketogenic diets ( n = 6) and Omega-3 fatty acids supplementation ( n = 4) did not significantly alter ALT. Fasting and MedDiet showed positive effects on surrogate biomarkers in MASLD. Larger, long-term isocaloric RCTs with standardized outcome reporting are warranted to confirm these findings.