Negative association between antioxidant vitamin intake and non-alcoholic fatty liver disease in Chinese non-diabetic adults: mediation models involving superoxide dismutase.

We aimed to explore the association between antioxidant vitamin intake, oxidative stress related markers and non-alcoholic fatty liver disease (NAFLD) by a cross-sectional analysis. A total of 241 non-diabetic participants from a Chinese rural cohort were included. NAFLD was diagnosed by abdominal ultrasound (NAFLD, n = 71; Non-NAFLD, n = 171). Dietary intake was assessed by a 24-h food recall. Plasma oxidative stress related markers superoxide dismutase (SOD), glutathione reductase (GR) and 8-oxo-2'-deoxyguanosine(8-oxo-dG) were measured. The association between dietary antioxidant vitamin intake, oxidative stress related markers and NAFLD were analysed by Spearman correlation analysis and multiple logistic regression analysis. Mediation models were established to examine whether SOD mediated the association between dietary vitamin A or α-tocopherol intake and NAFLD. Spearman correlation analysis indicated that dietary vitamin A and α-tocopherol intake were positively correlated with SOD (p < .05). Multiple logistic regression analysis found plasma SOD, dietary vitamin A and α-tocopherol intake were inversely associated with NAFLD (all p < .05). Mediation analysis indicated that SOD significantly mediated the indirect effect of dietary α-tocopherol (mediated effect = 13.21% total effect) or vitamin A (mediated effect = 3.12% total effect) intake on NAFLD. Our study indicated that dietary vitamin A and α-tocopherol intake may contribute to protect from NAFLD in Chinese non-diabetics, and the associations were partly mediated by SOD. However, SOD only accounted for a minor percentage of the association between vitamin A intake and NAFLD. Thus, other mechanisms underlying antioxidant vitamin' protective effect on NAFLD need further exploration.