Oxidative markers in children with severe obesity following low-calorie diets supplemented with mandarin juice

Aim: To evaluate the effect of supplementing a hypocaloric diet with mandarin juice, a food with a high content of antioxidants (vitamin C, flavonoids and carotenoids), on biomarkers of oxidant/antioxidant status of severe obese children. Methods: Forty obese children were randomized into two groups pair-wise in a 4-week controlled intervention study. Both groups followed a hypocaloric diet. One group received additionally a supplementation of 500 mL of 100% mandarin juice daily. Clinical data, anthropometry, dietary intake and fasting blood samples were collected at baseline and after the intervention. Lipid peroxidation was assessed by circulating levels of malondialdehyde, and protein oxidation was determined by the concentration of plasma carbonyl groups. The antioxidant defence was evaluated by red cell-reduced glutathione and plasma levels of α-tocopherol and vitamin C. Results: The supplemented group experienced a decrease in the levels of malondialdehyde (−9.6%, p = 0.014) and carbonyl groups (−36.1%, p = 0.006) and an increase in antioxidants (α-tocopherol +16.1%, p = 0.006, glutathione +36.1%, p