Dietary Index for Gut Microbiota and the Odds of Metabolic Dysfunction-Associated Fatty Liver Disease in Overweight and Obese Children and Adolescents: A Cross-Sectional Study

Abstract

BACKGROUND AND AIMS: Metabolic dysfunction-associated fatty liver disease (MAFLD) is increasingly prevalent among children and adolescents with overweight or obesity, posing a growing public health challenge. Emerging evidence highlights the gut microbiota as a critical mediator in MAFLD pathogenesis, yet few studies have explored dietary factors influencing this axis in pediatric populations. This cross-sectional study investigated the association between the Dietary Index for Gut Microbiota (DI-GM) and MAFLD. METHODS: A total of 505 Iranian youths aged 7-18 years enrolled in a national obesity registry. Dietary intake was assessed via a validated 147-item Food Frequency Questionnaire. MAFLD was diagnosed according to international expert consensus, requiring ultrasound‑confirmed hepatic steatosis in the presence of overweight/obesity or other metabolic abnormalities. RESULTS: Multivariable logistic regression models revealed that higher DI-GM scores were significantly associated with lower odds of MAFLD (OR per unit increase: 0.80, 95 CI: 0.71-0.91; p < 0.001). Participants in the highest DI-GM quartile had markedly reduced risk compared to the lowest quartile (OR: 0.42, 95 CI: 0.22-0.81). Notably, the inverse association was significant only among post-pubertal participants. Mediation analysis indicated that liver enzymes-alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), and aspartate aminotransferase (AST)-partially explained this relationship, accounting for 20.0, 19.2, and 6.7 of the association, respectively. CONCLUSION: These findings underscore the potential of microbiota-oriented dietary strategies to mitigate MAFLD risk in pediatric populations with obesity.