Association between dietary fat and antioxidant status of Tunisian type 2 diabetic patients

BACKGROUND: The antioxidant enzymes: superoxide dismutase (Cu/Zn SOD) and glutathione peroxidase (GSH-Px) provide a defense against the damage of cells by reactive oxygen species, which increased in diabetic state. It was demonstrated that dietary treatment could improve the antioxidant status in patients with type 2 diabetes mellitus. This study was undertaken to determine if erythrocyte Cu/Zn SOD and GSH-Px activities correlate with dietary nutrients in 35 selected type 2 diabetic patients (21 women and 14 men) without diabetic complications. RESULTS: We found that erythrocyte Cu/Zn SOD was diminished in patients with poor controlled diabetes and GSH-Px activity was significantly decreased in obese compared with non-obese type 2 diabetic patients (1.07+/-0.87 and 2.36+/-1.99 U/ml, respectively; P=0.024). Both erythrocyte Cu/Zn SOD and GSH-Px activities were positively correlated to erythrocyte omega3-polyunsaturated fatty acids (PUFA). In non-obese diabetic patients, only GSH-Px activity was correlated negatively to the fraction of linoleic acid (18:2omega6) and arachidonic acid (20:4omega6) in erythrocytes phospholipids. CONCLUSIONS: The data of this study reveal that activities of erythrocyte antioxidant enzymes were altered in type 2 diabetic patients. Further studies are needed to determine if diet supplemented with omega3-PUFA is required to improve antioxidant defense system in diabetic state.