Among 3,048 U.S. adults with steatotic liver disease (2,146 MASLD, 902 MetALD) followed across the 2005–2018 NHANES cycles, 306 deaths occurred. In MASLD patients, the highest dietary inflammatory index (DII) tertile was associated with a 97% increase in all-cause mortality (HR 1.97), while the highest composite dietary antioxidant quality score (CDAI) and dietary antioxidant quality score (DAQS) tertiles were associated with roughly 50–53% lower mortality risk. In MetALD patients, pro-inflammatory diet effects were even more pronounced — middle and top DII tertiles carried 4.95- and 3.91-fold mortality risks respectively. Mediation analysis implicated platelet count and the platelet-to-HDL ratio as partial biological bridges in MASLD, consistent with inflammation-driven thrombotic pathways.
Fatty liver disease now affects roughly one-quarter of the global population, yet dietary guidance beyond caloric restriction remains underspecified in clinical practice. This study adds meaningful granularity: it is among the first to test dietary antioxidant indices specifically in MetALD — the moderate-drinking subtype most clinicians encounter but least research covers. Effect sizes are notably large, though the observational design using single 24-hour dietary recalls limits causal inference, and confounding by overall diet quality, socioeconomic status, and disease severity cannot be fully excluded. Still, the consistency across two distinct antioxidant indices and the dose-response pattern strengthen the signal. Clinically, this supports recommending Mediterranean-style, polyphenol-rich eating patterns as an adjunct to weight management in patients with any SLD subtype — a nudge toward making anti-inflammatory dietary scoring a routine clinical tool.
