Abstract

Diabetic mellitus in an older population is associated with increased basal oxidative stress and free radical accentuated by hyperglycemic challenge. Enhanced free radical in diabetic elderly can cause the oxidative damage and such damage can be protected by antioxidant defense system. It is believed that vitamin C, A and E are the most abundant and effective antioxidants in human plasma. The purpose of this study was to determine the antioxidant status in Korean diabetic elderly using the case-control study. The antioxidant status was examined by determining plasma levels of antioxidant vitamins (vitamin C, A, E, beta-carotene), total antioxidant status (TAS) and thiobarbituric acid reactive substance (TBARS) and intakes of vitamin C, A, beta-carotene and retiol. Fasting glucose and HbA1c levels and serum lipid profiles (triglyceride (TG), total cholesterol, HDL-cholesterol and LDL-cholesterol) were also determined. Diabetic subjects were 122 elderly persons over 60 years old, visiting public health center, and control subjects were 96 healthy elderly persons living in Ulsan, Korea and they were matched by age, gender, smoking and drinking status. The diabetic and control subjects were divided into sub-groups according to the status of using diet therapy and vitamin supplement. The subjects were interviewed to collect data on their general characteristics, disease history, vitamin supplement, diet therapy and health-related habits by questionnaires. Their dietary intakes were obtained by means of semi-quantitative food frequency questionnaires (SQFFQ). Fasting plasma glucose and HbA1c levels were significantly higher in diabetes than in control subjects, and plasma total cholesterol level of diabetes was not significantly different from that of control subjects. However serum HDL cholesterol level of diabetes was significantly lower and serum TG level of diabetes was significantly higher than those of control group. The average vitamin A and beta-carotene intakes of diabetes were significantly higher than those of control subjects. There was no significant difference in plasma vitamin C, beta-carotene, and TBARS levels between two groups, but plasma vitamin A, E and TAS levels were significantly higher in diabetes than those in control group. Plasma vitamin A and TAS levels of diabetic subjects using diet therapy were higher than those of control using diet therapy, and plasma vitamin E, beta-carotene and TAS levels of diabetic subjects using vitamin supplements were significantly higher than those of controls using vitamin supplements. These results suggested that diabetic mellitus could enhance antioxidant defences against reactive oxygen species and interest in healthy eating such as consumption of more antioxidant nutrients.

• Keywords: diabetes; elderly; TAS; vitamin A; vitamin C; vitamin E