Association between plant-based diet quality and metabolic dysfunction-associated steatotic liver disease (MASLD)...

Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly non-alcoholic fatty liver disease (NAFLD), is a growing public health concern with limited effective treatments. Diet quality may influence MASLD risk, yet the role of plant-based dietary patterns in diverse populations remains unclear.

To evaluate the associations of plant-based dietary patterns with liver fat content or MASLD prevalence in multiethnic older adults.

We analyzed cross-sectional data on 1598 participants of five racial and ethnic groups in the Adiposity Phenotype Study, nested within the Multiethnic Cohort Study. Participants' adherence to three established plant-based diet indices was estimated from their food frequency questionnaire responses: overall plant-based diet index (PDI), healthful plant-based diet index (hPDI), and unhealthful plant-based diet index (uPDI). Magnetic resonance imaging was used to quantify liver fat and identify MASLD cases. Multivariable-adjusted linear regression of liver fat and logistic models of MASLD were performed to determine their associations with the plant-based diet indices, adjusting for demographic, lifestyle, and anthropometric covariates.

Higher hPDI scores were associated with lower liver fat content (adjusted mean liver fat for 4th (5.39%) vs. 1st quartile (6.52%) of hPDI) and reduced likelihood of MASLD (OR for 4th vs. 1st quartile = 0.58 (95% CI: 0.41-0.81)). The hPDI-MASLD association varied by race and ethnicity (p-heterogeneity = 0.001), with stronger inverse associations observed among Latino and White participants than among African American, Japanese American, or Native Hawaiian participants. No consistent associations were observed for PDI or uPDI. Among hPDI components, higher nut and lower animal fat intakes were associated with lower hepatic adiposity.

Greater adherence to a healthful plant-based diet is associated with lower liver fat and MASLD prevalence, with some racial and ethnic variation. These findings underscore the importance of plant-food quality and may inform dietary strategies for MASLD prevention in heterogeneous populations.