Introduction: There is limited evidence on the role of an anti-/pro-inflammatory diet in the prevention of non-alcoholic fatty liver disease (NAFLD). We aimed a) to assess the pro-inflammatory diet profile and its association with NAFLD diagnosed by ultrasound, and b) to analyze the relationship between a pro-inflammatory diet and surrogate markers of liver disease in the general adult population of Iran.

Methods: A cross-sectional study was conducted on 3110 (45% female) general adults (≥18 years old) of the Amol Cohort Study (AmolCS). Ultrasound imaging was utilized to diagnose NAFLD. Liver markers, including fatty liver index, aspartate transaminase (AST)/alanine transaminase (ALT) ratio, and hepatic steatosis index (HSI), were also calculated. Dietary inflammatory index was calculated by a validated 168-item semi-quantitative food-frequency questionnaire (FFQ) and was adjusted for daily calorie intake using the residual method.

Results: Participants in 3rd tertile of E-DII scores (pro-inflammatory diet) had the highest odds ratio (OR) for NAFLD assessed by FLI adjusted model (OR tertile3vs.1=1.78, 95% CI= 1.28-2.47; Ptrend = 0.003). Participants in the highest i.e., most pro-inflammatory tertile had the highest odds of NAFLD by hepatic steatosis index (HSI) in a full adjusted model (OR tertile3vs.1=1.43, 95% CI= 1.11-1.85; Ptrend = 0.002). Similar results were also obtained for NAFLD assessed by ultrasound (OR tertile3vs.1=1.54, 95% CI= 1.23-1.93; Ptrend = 0.004). For the AST/ALT ratio, no significant association was identified.

Conclusions: Our findings showed an association between higher pro-inflammatory properties of diet and poor hepatic health assessed by ultrasound and surrogate markers of liver disease. Therefore, strategies to promote an anti-inflammatory diet should be considered to prevent NAFLD in adults.