Increased magnesium intake does not mitigate MAFLD risk associated with magnesium deficiency.

Serum magnesium cannot accurately assess magnesium deficiency. The association between magnesium deficiency and metabolic dysfunction-associated fatty liver disease (MAFLD) remains unclear. Selecting 3,377 participants in the United States, we assessed the degree of magnesium deficiency in the population using magnesium depletion score (MDS). Multinomial logistic regression assessed the association between magnesium deficiency and MAFLD. Subgroup analyses assessed the association between dietary magnesium intake and MAFLD under different magnesium deficiency statuses. Structural equation modeling (SEM) revealed mediation effects. Magnesium deficiency was associated with MAFLD (ORseverevs.none: 1.69, 95%CI: 1.16-2.46; p for trend < 0.001). Magnesium intake was negatively associated with MAFLD only in the subgroup without magnesium deficiency (p for trend < 0.01). Inflammation, oxidative stress, and aging significantly mediated the association between MDS and MAFLD (all p < 0.05). In American adults, magnesium deficiency assessed by MDS might be a risk factor for MAFLD, with inflammation, oxidative stress, and aging potentially being key mechanisms. Simply increasing magnesium intake would not mitigate MAFLD risk associated with magnesium deficiency. Correcting magnesium deficiency might prevent MAFLD.