Blood antioxidant defense system and dietary survey of elderly diabetic men

Levels of antioxidants, activities of free radical scavenging enzymes and extent of lipid peroxidation were determined in the blood of 37 elderly diabetic men and 30 control elderly men, 16 without cardiovascular disease (CVD) and 14 with CVD. The mean +/-S.D. of the ages of the diabetic men was 66+/-5 and those of the control men was 69+/-5, while serum glucose levels of diabetic men were 213+/-81 mg/dl and that of control subjects were 95+/-14 mg/dl. Among the diabetic men, 13 men were obese with body mass index>30, 26 men had poor control of diabetes (glycohemoglobin>7%) and 25 men had retinopathy. The diets of the control and diabetic men were evaluated. Blood samples were collected and analyzed for major endogenous antioxidant defense parameters and lipid peroxidation. The results show that diabetic men had significantly lower blood reduced glutathione levels (p<0.001) and erythrocyte (RBC) CuZn-superoxide dismutase activity (p<0.001) when compared to control groups with or without CVD. There was no significant differences in plasma vitamin E levels and the activities of catalase and glutathione peroxidase in RBC among the three groups. The extent of lipid peroxidation was highest in diabetic patients, intermediate in controls with CVD, and lowest in controls without CVD. The results suggest that a decline of endogenous antioxidant defense capability contributes to oxidative stress in the diabetic elderly patients. Dietary survey showed that there were no differences in the nutrient intakes of diabetic and control groups. It appears that individual dietary advice is needed for a large portion of diabetic patients in view of their poor glycemic control, hypertriglyceridemia and obesity.