Antioxidant Vitamins and Lipid Peroxidation in Patients with Type 1 Diabetes Mellitus

Abstract

It has been postulated that oxidative stress may be increased and antioxidant defenses reduced in diabetes patients. Twenty-four patients with type 1 diabetes mellitus (DM) (12.8±1.7 years) and 24 nondiabetics (12.5±2.1 years) were included in this study. Serum total cholesterol and LDL-cholesterol levels were significantly higher in diabetic than in nondiabetic control subjects, but serum levels of triglyceride, retinol, tocopherol, and β-carotene were significantly lower. Both β-carotene and tocopherol levels inversely correlated with HbA_(1c), suggesting perhaps that low serum antioxidant level enhance the glycosylation of hemoglobin. Subjects with type 1 DM had lipid peroxide levels similar to those of nondiabetic control subjects, suggesting that peroxidation of circulating lipid is not increased in uncomplicated diabetics. The correlation between antioxidants and serum lipids were as follows: retinol and LDL (r=-0.36, p=0.019); retinol and total cholesterol (r=-0.35, p=0.020), tocopherol and LDL (r=-0.47, p=0.002); tocopherol and cholesterol (r=-0.49, p=0.001; β-carotene and LDL (r=-0.51, p=0.001). Overall, the results of this study were that serum lipid peroxide in patients with type 1 DM was similar to those of control subjects and antioxidants such as retinol, tocopherol and β-carotene were lower than those of nondiabetic control subjects, and negatively correlated with serum total cholesterol and LDL-cholesterol.