Correlation of Nonalcoholic Fatty Liver Disease with Dietary Folate and Serum Folate in U.S. Adults: Cross-Sectional Analyses from National Health and Nutrition Examination Survey 2009-2018.

Nonalcoholic fatty liver disease (NAFLD) is a global health problem, and dietary intervention is still considered one of the primary interventions. This study aimed to examine cross-sectional associations between dietary and serum levels of folate and NAFLD. We conducted a study of 7543 adults who participated in the National Health and Nutrition Examination Survey, 2009-2018. NAFLD status was determined by a fatty liver index (FLI) value ≥60. Multivariable logistic regression models were used to estimate associations between folate and NAFLD. Almost half (45%) of the patients were classified as having NAFLD based on the FLI. In the fully adjusted model, participants in the highest quartile of dietary total folate and food folate were found to have a lower prevalence of NAFLD than those in the lowest quartile [odds ratio (OR) = 0.582; 95% confidence interval (CI) = 0.350-0.968; and OR = 0.737; 95% CI = 0.611-0.888, respectively], and the fourth quartile values of serum total folate and 5-methyl-tetrahydrofolate were significantly negatively associated with NAFLD prevalence (OR = 0.664; 95% CI = 0.495-0.891; and OR = 0.712; 95% CI = 0.532-0.954, respectively). Subgroup analyses revealed that this beneficial association was more significant in women (OR = 0.526; 95% CI = 0.329-0.843; < 0.001) than in men (OR = 0.805; 95% CI = 0.546-1.186). Higher dietary folate intake and serum folate levels are associated with a lower NAFLD prevalence among U.S. adults and the trend is more pronounced among women, indicating opportunities for dietary NAFLD interventions.