Antioxidant supplements reduced oxidative stress and stabilized liver function tests but did not reduce inflammation in a randomized controlled trial in obese children and adolescents

Abstract

Oxidative stress and low-grade systemic inflammation may contribute to the pathogenesis of obesity-induced comorbidities, including nonalcoholic fatty liver disease. Increasing intake of dietary antioxidants might be beneficial, but there are few data in obese children. To examine the effect of antioxidant supplementation on biomarkers of oxidative stress, inflammation, and liver function, we randomly assigned overweight or obese children and adolescents (n = 44; mean ± SD age: 12.7 ± 1.5 y) participating in a lifestyle modification program to a 4-mo intervention with daily antioxidants (vitamin E, 400 IU; vitamin C, 500 mg; selenium, 50 μg) or placebo. We measured anthropometrics, antioxidant status, oxidative stress (F(2)-isoprostanes, F(2)-isoprostane metabolites), inflammation, liver enzymes, fasting insulin and glucose, and lipid profile at baseline and endpoint. There was a significant treatment effect of antioxidant supplementation on antioxidant status [α-tocopherol, β = 23.2 (95% CI: 18.0, 28.4); ascorbic acid, β = 70.6 (95% CI: 51.7, 89.4); selenium, β = 0.07 (95% CI: 0.01, 0.12)] and oxidative stress [8-iso-prostaglandin F2α, β = -0.11 (95% CI: -0.19, -0.02)] but not on any of the inflammatory markers measured. There was a significant treatment effect on alanine aminotransferase [β = -0.13 (95% CI: -0.23, -0.03)], a trend toward a significant effect on aspartate aminotransferase [β = -0.04 (95% CI: -0.09, 0.01)], and no significant effect on γ-glutamyltransferase [β = -0.03 (95% CI: -0.11, 0.06)]. In summary, antioxidant supplementation for 4 mo improved antioxidant-oxidant balance and modestly improved liver function tests; however, it did not reduce markers of systemic inflammation despite significant baseline correlations between oxidative stress and inflammation. The study was registered at clinicaltrials.gov as NCT01316081.