International Journal of Preventive Medicine (Int J Prev Med)2008-7802572013091983540ENPhD student of nutrition sciences, Students Research Committee, Nutrition Faculty of Shahid Beheshti University of Medical Sciences, Tehran, IranPhD of biochemistry of nutrition, Tabriz Nutrition Research Center, Food Sciences and Food Industry department, Health and Nutrition Faculty of Tabriz University of Medical Sciences, Tabriz, IranRheumatologist- Rheumatology Research Team, Imam Reza Hospital of Tabriz University of Medical Sciences, Tabriz, IranPhD of Epidemiology of Nutrition, Tabriz Nutrition Research Center, Nutrition and Diet Therapy department, Health and Nutrition Faculty of Tabriz University of Medical Sciences, Tabriz, IranDiet Therapy department, Nutrition faculty, Shahid Beheshti University of Medical Sciences, Tehran, Iran20130919<p class="Pa7"><strong>Background: </strong>This study aims to investigate the effect of antioxidants supplement on clinical outcomes and antioxidant parameters in rheumatoid arthritis (RA).</p> <p class="Pa7"><strong>Methods: </strong>The pre‑post study was conducted on 40 female patients with RA in 12 weeks that taken daily one &ldquo;Selenplus&rdquo; capsule contained 50 &mu;g selenium, 8 mg zinc, 400 &mu;g vitamin A, 125 mg vitamin C, and 40 mg vitamin E. About 5 mL venous blood sample was taken from all participants and disease activity score (DAS) was determined by DAS‑28 formula and high‑sensitive C‑reactive protein (hs‑CRP). Glutathione peroxidase (GPX) and superoxide dismutase (SOD) were measured by spectrophotometric kit and catalase (CAT) was measured by Abei method. Total antioxidant capacity (TAC) was determined by spectrophotometric kit. Distribution of the variables was assessed using histogram with normal curve as well as Kolmogorov‑Smirnov test and data were analyzed with paired <em>t</em>‑test for differences between pre‑post data using SPSS software version 13.5.</p> <p class="Pa7"><strong>Results: </strong>Out of 40 patients, 39 completed the study. DAS‑28 score and hs‑CRP have changed (<em>P </em>&lt; 0.01 for both), while the number of swollen and painful joints did not reduce significantly. TAC, GPX, SOD, and CAT increased significantly (<em>P </em>&lt; 0.01 for all variables).</p> <p class="Pa7"><strong>Conclusions: </strong>Our findings showed that antioxidants may improve disease activity significantly, but it did not affect the number of painful and swollen joints and increased erythrocyte antioxidant levels. Antioxidants may be useful for controlling of clinical outcomes and oxidative stress in RA.</p> <strong>Keywords: </strong>Antioxidants, dietary supplements, nutrition, oxidative stress, rheumatoid arthritishttp://ijpm.mui.ac.ir/index.php/ijpm/article/view/1246http://ijpm.mui.ac.ir/index.php/ijpm/article/download/1246/1637