Effects of weight reduction on the enzymatic antioxidants and its association with dietary intakes of copper, zinc, iron, selenium and magnesium in obese women

Body mass index (BMI) is a generally accepted indicator of body weight and obesity. A BMI>30 indicates obesity, which is regarded as a risk factor for many diseases, because their pathogeneses are associated with increasing numbers of free radicals derived from oxygen. The present study was a clinical trial carried out in order to study the effects of weight loss on enzymatic antioxidants and its association with dietary intakes of copper, zinc, iron, selenium and, magnesium in obese women. Thirty obese women, 19-50 years old, of whom informed consent was obtained, were included in the study. Information was collected on their general characteristics, and anthropometric measurements were made. A diet with a 500- to 1000-calorie deficit was recommended to the subjects, on the basis of micronutrient intakes estimated through a 24-hour dietary recall questionnaire 3 days before and after the intervention. The aim was to bring about a weight loss of 10%. A 10-ml blood sample was taken from each subject, before and after intervention, for enzymatic measurement of enzymatic antioxidants in the red blood cells. Weight loss caused a significant increase (p<0.01) in the mean glutathione reductase (GR) and catalase (CAT); no statistically significant change occurred in the mean values of superoxide dismutase (SOD) or glutathione peroxidase (GPX). The only association between the enzymes and trace elements (Cu, Zn, Fe, Mg, Se) was a negative linear correlation between daily zinc intake and GPX before intervention (r=0.395, p<0.05) A 10% reduction in body weight might be an effective step toward increasing levels of enzymatic antioxidants which would minimize injuries caused by free radicals and reduce oxidative stress in obese women. Attention should be paid to the dietary intakes of micronutrients essential for the activities of these enzymes.