IS OBESITY ASSOCIATED WITH INCREASED PLASMA LIPID PEROXIDATION AND OXIDATIVE STRESS IN WOMEN?

  Abstract INTRODUCTION: The role of obesity in diabetes mellitus, hyperlipidemia, colon cancer, sudden death and other cardiovascular diseases has been confirmed by many studies. In this study, it was hypothesized that obesity is an independent risk factor for lipid peroxidation and decreased activity of cytoprotective enzymes in humans. methods: To test the study hypothesis, we assessed lipid peroxidation by measuring the concentrations of plasma malondialdehyde (MDA) and the activity of erythrocyte copper-zinc superoxide dismutase (CuZn-SOD), glutathione peroxidase (GPX) and catalase (CAT) in ۲۵ obese women (BMI=۳۰-۴۰ Kg/m۲) and ۲۵ women with healthy BMI (۱۹-۲۵Kg/m۲). results: The concentration of plasma MDA was significantly higher (P<۰.۰۰۱) in obese women (۳.۴± ۰.۷ µmol/L) compared to women with healthy BMI (۱.۴± ۰.۳ µmol/L). Furthermore, there was a significantly positive correlation (r =۰.۷۵, P<۰.۰۰۰۱) between BMI and plasma MDA. On the other hand, women with healthy BMI had significantly higher (P<۰.۰۰۱) erythrocyte CuZn-SOD (۸۷۳± ۵۲ U/g Hb) and GPX (۶۴.۷± ۱۴.۲ U/g Hb) activity than obese women (۶۶۰± ۳۹ U/g Hb) and (۴۸.۵± ۱۳.۱ U/g Hb), respectively. Furthermore, erythrocyte CuZn-SOD and GPX activity were negatively correlated with BMI (r =-۰.۵۲, P<۰.۰۰۰۱ and r =-۰.۴۲, P<۰.۰۰۱), respectively. No significant difference was observed between two groups in erythrocyte CAT activity. CONCLUSIONS: From these observations, it is concluded that obesity even in the absence of smoking, diabetes, renal or liver disease can decrease the activities of body’s protective antioxidants, and can enhance the systemic oxidative stress.     Keywords: Obesity, Lipid peroxidation, Cytoprotective enzymes, Oxidative stress, Women.