Abstract

Background & aims: Vitamin D has been proposed to have a protective role against oxidative stress. The present study was conducted to test the hypothesis that suboptimal levels of 25(OH)D are related to oxidative/antioxidative biomarkers in adults independently of obesity. Methods: In this case–control study, 140 subjects with obesity and 90 age- and sex-matched 25(OH)D sufficient normal weight controls were selected. Subjects with obesity were categorized as 25(OH)D sufficient, insufficient, and deficient based on their serum 25(OH)D concentrations. Serum malondialdehyde (MDA), total oxidant status (TOS), and total antioxidant capacity (TAC) as well as erythrocytes superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) along with serum paraoxonase-1 (PON1) and arylesterase (AREase) activities were assessed. Results: Serum concentrations of 25(OH)D were inversely correlated with BMI, WC, fat mass, and visceral fat. Serum levels of MDA and TOS, and erythrocyte SOD activities were significantly higher, whereas, serum TAC, PON1, and AREase were significantly lower in subjects with obesity compared to the controls (p < 0.0001). 25(OH)D deficient obese subjects exhibited higher serum levels of MDA as well as erythrocyte SOD activity (p < 0.05) and lower serum levels of TAC (p < 0.0001), PON1 (p < 0.05), and AREase (p < 0.0001) compared to obese subjects with 25(OH)D sufficiency and controls even when adjusted for BMI. Conclusions: The present findings demonstrated a strong association between the severity of 25(OH)D deficiency and oxidative/antioxidative related parameters independently of obesity. © 2021 European Society for Clinical Nutrition and Metabolism