Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 38 2 2009 06 15 79 89 N Aryaeian Dept. of Nutrition, School of Public Health, Iran University of Medical Sciences, Iran M Djalali Dept. of Nutrition and Biochemistry, School of Public Health, Tehran University of Medical Sciences, F Shahram Rheumatology Research Center, Shariaty Hospital, Tehran University of Medical Sciences, Iran A Djazayeri 2Dept. of Nutrition and Biochemistry, School of Public Health, Tehran University of Medical Sciences MR Eshragian Dept. of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Scien N Nadery Rheumatology Research Center, Shariaty Hospital, Tehran University of Medical Sciences, Iran F Fatehi Dept. of Nutrition, School of Public Health, Iran University of Medical Sciences, Iran M Zarei Dept. of Nutrition, School of Public Health, Iran University of Medical Sciences, Iran M Chamari Dept. of Nutrition, School of Public Health, Iran University of Medical Sciences, Iran 2015 10 03 Background: Reactive oxygen species (ROS) have important role in the etiology and pathogenesis of Rheumatoid Arthritis (RA). We investigated the effect of conjugated linoleic acids (CLAs) and vitamin E on lipid peroxidation. Methods: In a randomized, double-blind placebo, controlled, clinical trial 87 patients with active RA were enrolled. They were divided into 4 groups, received one of the following daily supplement for 3 months; 1- group C: 2.5gr CLA, that con­tained 2 gr 50:50 mix of cis 9-trans11 and trans 10-cis 12 CLAs, 2- group E: 400mg Vitamin E, 3- group CE: CLAs  plus vita­min E, 4- group P: placebo. After supplementation Glutathione peroxidase (GSH-Px) level increased in C, E and CE groups, CE group had  lower GSH-Px than P group(P≤ 0.05). Results: Glutathione reductase (GR) increased in CE, C and P groups. Catalase increased in all groups, but enhancement was significant in C and CE. Superoxide dismutase (SOD) decreased in E and C (P≤ 0.05). Catalase and SOD did not show signifi­cant differences between groups. Malondialdehyde (MDA) decreased significantly in all groups but this decrease was only significant in CE in comparison with other groups. Conclusion:  CLAs might be useful in reducing oxidative stress in RA https://ijph.tums.ac.ir/index.php/ijph/article/view/3192 https://ijph.tums.ac.ir/index.php/ijph/article/download/3192/2991