The present study aimed to determine the effect of taking antioxidant vitamins including vitamins E and C in reducing oxidative stress levels and improving blood parameters. This double-blind randomized controlled trial study was conducted among the employees working in different parts of a power plant in Semnan, Iran, in 2017. A total of 91 employees were randomly allocated to four groups including vitamin E (400 units per day), vitamin C (1000 mg per day), vitamin E + C for 90 days, and control. The levels of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (Cat), and total antioxidant capacity (TAC) in plasma, and hematological parameters were measured in the participants before and after the intervention. A significant increase was seen in the mean level of SOD, Cat, and TAC in the vitamin-treated groups as well as a significant decrease in mean MOD in vitamin C and vitamin E groups after the intervention. In the intervention groups, the number of red blood cells, hematocrit, and the level of mean corpuscular hemoglobin (MCH) and MCH concentration significantly increased. After the intervention, the mean levels of MDA, SOD, and Cat in vitamin E group were significantly lower than the control group. The mean level of TAC decreased only in the vitamin C group compared to the control group. Taking vitamins E and C as nonenzymatic scavengers of free radicals appears to decrease lipid peroxidation and increase the level of antioxidant enzymes, which can be imbalanced by exposure to extremely low-frequency electromagnetic fields in power plant employees. Furthermore, some hematological parameters can be improved by consuming these vitamins.
Keywords: Catalase; malondialdehyde; red blood cell; superoxide dismutase; total antioxidant capacity.