ABSTRACT
Aims: The purpose of this study was to evaluate the effect of vitamin E supplementation on oxidant-antioxidant balance in chronic renal failure patients treated by hemodialysis. Study Design: The study utilized a randomized experimental design. The experimental intervention consisted of vitamin E supplementation Place and Duration of Study: 40 patients on hemodialysis (M/W=22/18; 36±12 years) received nutritional councils based on the NKF K/DOQI (National Kidney Foundation- Kidney Disease Outcomes Quality Initiative) guidelines. Patients were randomized into 2 groups:one was used as control and the second group was treated by vitamin E supplementation (100mg/day=146IU/d) during 30 days. Methodology: Pro-oxidant status was assessed by thiobarbituric acid reactive substances, hydroperoxides and carbonyls analysis. Antioxidant defence was performed by the analysis of Superoxide dismutase, Catalase, Glutathione reductase activities and Vitamin E amounts. Results: At 30 days of supplementation, in treated patients compared to controls, levels of triacylglycerols and total cholesterol were unchanged. Hydroperoxides concentrations were decreased (p<0.001) while thiobarbituric acid reactive substances concentrations were unchanged. Carbonyls levels were decreased (p<0.001). High concentrations of vitamin E were noted in treated group (p<0.01). Similar superoxide dismutase activity was noted. However, an increase in vitamin E concentrations, catalase and glutathione reductase activities were observed in treated group (p<0.01). Conclusion: In conclusion, in hemodialysis patients, vitamin E supplementation was without effect on lipid profile. However, vitamin E exerts a protective effect on cardiovascular diseases by decreasing radical attack of biological molecules and increasing antioxidant defense.
ABSTRACT
To study antioxidant role of zinc, the effects of dietary zinc deficiency and vitamin E supplementation on lipid peroxidation were studied. Levels of zinc and vitamin E in blood and liver were also measured. Forty Sprague-Dawley male rats aging 8 weeks old were used as experimental animals. Zinc deficient diet (Zn, 0 ppm), zinc normal diet (Zn, 36.5 ppm), and vitamin E supplemented diet (1,000 IU alpha-tocopherol/kg of diet) were used as experimental diet. During the first three weeks, rats were divided into zinc normal (ZnN, 8 animals) and zinc deficient (ZnD, 32 animals) group. Eight rats from each group were sacrificed to get blood and liver after 3 weeks of experiment. The remaining 24 zinc deficient rat were then divided into zinc normal (ZnDN), zinc deficient (ZnDD), vitamin E supplemented (ZnDE) diet groups. After another 3 weeks of experiment, all animals were sacrificed as well. Thiobarbituric acid reactive substance (TBARS) levels in plasma and liver, conjugated diene levels in liver were measured as lipid peroxidation index. There were no significant differences in food intake, body weight gain, and food efficiency ratio among groups. Weights of liver per 100 g body weight were not significantly different. There were no significant differences in Zn levels in serum. Plasma and liver TBARS level, and liver conjugated diene level were significantly lower in ZnDE than in ZnDN or ZnDD, and significantly higher in ZnDD than in ZnDN. Therefore, it seems that lipid peroxidation is accelerated by dietary zinc deficiency and recovered partly by vitamin E supplementation.