Aim: Obesity shortens the life period and decreases its quality, causing several complications. Recently, oxidative stress produced by lipid peroxydation is considered a cardiovascular risk factor. In this study, we aimed to investigate the relationship between weight loss with lipid profile, insulin resistance, and lipid peroxidation products malondialdehyde (MDA, oxidant) and paraoxonase-1 (PON1, antioxidant) levels which is protective in atherosclerosis, and to evaluate alteration on oxidative stress.

Methods: Patients diagnosed as obese at the Endocrinology and Metabolic Diseases Outpatient Clinics of Inonu University Faculty of Medicine between December 2005 and February 2008 were studied. 103 patients were included in the study. Study population was divided into two treatment groups. In the first group, 120 mg of orlistat, three times daily, and in the second group, sibutramine 15 mg per day were given in addition to appropriate diet therapy. The patients were evaluated at the end of three months treatment period.

Results: Dramatic changes in body weight, Body Mass Index (BMI), and waist and hip circumference were observed during the three-month evaluation in patients receiving orlistat or sibutramine. Additionally, significant improvements were measured in systolic-diastolic blood pressure levels, lipid levels, and insulin resistance. The decrease in the MDA level and the increase in the PON level were similar and significant in both patient groups.

Conclusion: The treatment of obesity, aimed at reducing body weight, acts to reduce oxidative stress by increasing paraoxonase-1 activity (antioxidant) and reducing the amount of the peroxidation product malondialdehyde (oxidant), regardless of the type of medication administered.

Keywords: Malondialdehyde, obesity, orlistat, paraoxonase, sibutramine