Blood redox status is associated with the likelihood of nonalcoholic fatty liver disease irrespectively of diet's total antioxidant capacity

It is well established that oxidative stress is implicated in nonalcoholic fatty liver disease pathogenesis, whereas the dietary intake of antioxidants has been reported to be low in patients with the disease. We hypothesized that blood redox status measurements would be associated with nonalcoholic fatty liver disease presence and severity, and that diet's total antioxidant capacity could moderate the aforementioned association. The study sample consisted of 73 patients with nonalcoholic fatty liver disease, of which 58 were matched by age, sex, and body mass index with 58 controls. Diet's total antioxidant capacity was estimated through the ferric-reducing antioxidant power, the total radical-trapping antioxidant parameter, and the Trolox equivalent antioxidant capacity scores, whereas blood redox status was assessed by measuring thiobarbituric acid reactive substances levels, the enzymatic activity of glutathione peroxidase, and serum resistance to oxidation. Diet's total antioxidant capacity scores and glutathione peroxidase activity were not significantly associated with the disease presence or severity. Both thiobarbituric acid reactive substances and serum resistance to oxidation were significantly associated with the likelihood of nonalcoholic fatty liver disease (odds ratios [ORs], 7.769 [P= .007] and 0.936 [P= .033], respectively), independently of abdominal fat level, degree of insulin resistance, blood lipid levels, markers of subclinical inflammation, and diet's total antioxidant capacity, but not with the disease histologic severity or stage. Our results support the association between blood redox status and the likelihood of nonalcoholic fatty liver disease regardless of diet's total antioxidant capacity.