Higher ultra-processed food intake was positively associated with odds of NAFLD in both US adolescents and adults: A national survey

BACKGROUND: The effect of ultra-processed foods (UPF) on NAFLD remains unclear. Related evidence for adult NAFLD is limited and no study has yet evaluated UPF’s impact on NAFLD in adolescence. METHODS: We used data from the National Health and Nutrition Examination Survey (2017-2018) with 806 adolescents and 2734 adults. UPF intake was estimated using dietary data from two 24-hour dietary recalls. NAFLD was defined by transient elastography. Logistic regression was used to estimate the multivariable OR and 95% CI for associations between UPF and NAFLD with survey weight adjustments. RESULTS: The mean UPF intake was 812 g/d in adolescents and 823 g/d in adults. A total of 12.4% of the adolescents and 35.6% of the adults had NAFLD. Higher UPF intake was associated with higher odds of NAFLD in both adolescents (OR (Quintile 5 vs. Quartile 1) = 2.34, 95% CI, 1.01, 5.41; p ( trend ) = 0.15) and adults (OR (Quintile 5 vs. Quintile 1) = 1.72, 95% CI, 1.01, 2.93; p ( trend ) = 0.002). In adults, ~68% and 71% of the association between UPF intake and NAFLD was mediated by body mass index and waist circumference (all p-values < 0.001), respectively. The results were similar for adolescents but not statistically significant. A higher UPF intake was associated with lower levels of serum albumin and higher levels of C-reactive protein in adults. CONCLUSIONS: Higher UPF intake was linked to higher NAFLD odds in both adolescents and adults, mainly because of elevated body fatness. If confirmed, reducing UPF intake may help prevent NAFLD in both adolescents and adults.