Relationship between Dietary Total Antioxidant Capacity and Oxidative Stress Markers in Patients with Knee Osteoarthritis

Background and purpose: Considering the pathologic importance of oxidative stress in osteoarthritis (OA), this study aimed to investigate the association between dietary total antioxidant capacity (DTAC) and oxidative stress markers in patients with knee OA. Materials and methods: In a cross-sectional study, dietary intakes of 152 patients with knee OA attending health centers in Zabol, Iran (January-May 2022) were evaluated using food frequency questionnaire (FFQ). Demographic and anthropometric data were collected and DTAC was calculated using ferric-reducing antioxidant power (FRAP) assay. Then, serum concentrations of malondialdehyde (MDA), total oxidant status (TOS), total antioxidant capacity (TAC), erythrocyte activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) were measured. The oxidative stress index (OSI) was also calculated by dividing TOS by TAC. Results: The mean serum concentrations of MDA (P< 0.001), TOS (P-trend< 0.001), and OSI (P-trend= 0.001) showed decreasing trends by increase in DTAC after adjustment for potential confounders. Serum TAC concentrations had increasing trend when DTAC increased (P-trend=0.027). No significant trend was found between erythrocyte activities of SOD, GPx, and DTAC. Conclusion: Higher DTAC was favorably associated with oxidative stress markers in patients with knee OA. Further prospective studies are required to confirm these findings.