Dietary index for gut-microbiota and the odds of metabolic dysfunction-associated fatty liver disease in overweight and obese children and adolescents

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 in 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, and MAFLD was diagnosed based on international consensus criteria. 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). Mediation analysis indicated that liver enzymes—ALT, GGT, and AST—partially explained this relationship, accounting for 20.0%, 19.2%, and 6.7% of the association, respectively. These findings underscore the potential of microbiota-oriented dietary strategies to mitigate MAFLD risk in pediatric populations with obesity.