Effects of Zinc Supplementation on Antioxidant Status and Lipid Peroxidation in Hemodialysis Patients

Objectives: This study was designed to determine the effects of zinc supplementation on oxidative stress in hemodialysis (HD) patients through evaluating total antioxidant capacity (TAC), whole blood glutathione peroxidase (GSH) level, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) level. Design and Setting: Double-blinded randomized controlled trialfrom October 2006 to December 2007 at Tabriz Imam Khomeini Hospital. Subjects: Sixty-five HD patients were randomly enrolled into 2 groups. Intervention: Patients received placebo in group A and zinc (100 mg/day) in group B for 2 months. After a washout period for 2 months, the groups were crossed over and the study was continued for an additional 2 months. Main outcome measures: Serum zinc concentration was measured using atomic absorption spectrophotometry. TAC, GSH level, and SOD activity were determined by commercial enzyme-linked immunosorbent assay kits. MDA level was measured using a thiobarbituric acid method. Results: The levels of serum zinc, TAC, GSH (P < .001 for all), and SOD activity (P < .001 for group A and P = .003 for group B) significantly increased after zinc supplementation whereas the serum level of MDA decreased after the same period (P = .003 for group A and P < .001 for group B). Conclusions: Zinc supplementation for 2 months improved the serum levels of zinc, antioxidant status, and lipid peroxidation in HD patients.