[Effect of multiple micronutrients supplementation on anti-oxidative activity and oxidized DNA damage of lymphocytes in children].

OBJECTIVE: To examine the effect of multiple micronutrients supplementation on anti-oxidative activity and decreasing oxidized DNA damage of lymphocytes in Chinese children.

METHODS: 82 healthy children in a rural areas, aged 9-11 years, were selected and randomized allocated into group receiving supplements and control group with each of them 41. 24-hour dietary recall was used to collect data on daily nutrient intakes of the research subjects. The subjects in the supplement group were given vitamin A (VA) 600 microg, beta-carotene (beta-C) 1.0 mg, vitamin E (VE) 100 mg, vitamin C (VC) 300 mg and Na2SeO3(Se) 200 microg in a tablet on daily base while those in the control group took a same-sized color placebo tablet. The trial lasted 8 weeks. 5 ml blood samples from each subject were taken during 7 to 9 o'clock in the morning. DNA damage of lymphocytes and levels of plasma VA, VE, VC, beta-C, Se, malondialdehyde (MDA), activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were then analyzed twice before and after the 8-week of trial.

RESULTS: The low intakes of VA, VC and Se only accounted for 50.6%, 65.6% and 67.3% of their recommended nutrient intake (RNI) respectively. After the trial, levels of plasma beta-C, VA, VE, VC and Se in the supplemented group increased by 13.4%, 32.8%, 11.5%, 46.9% and 24.6% respectively, compared with the control group, indicating that nutritional status regarding antioxidant nutrients had largely been improved. GSH-Px activity had a significant increase in the supplement group than before the supplement and in the control group (P < 0.01). GSH-Px before the trial (the 100.4 U/ml) also showed significant increase after the trial (161.7 U/ml) (P < 0.01). However, the values of SOD and MDA significantly decreased after the trial. Analysis of DNA damage indicated that there was no significant difference in the intrinsic damage of DNA (P > 0.05). Significant decreases of oxidized DNA damage induced by 5 micromol/L, 10 micromol/L and 25 micromol/L H2O2 were found more in peripheral lymphocytes of the supplemented group, than in pre-supplement and the control group after the trial (P < 0.01).

CONCLUSION: Supplementation of multiple micronutrients could effectively increase the levels of beta-C, VA, VE, VC and Se in plasma, and GSH-Px activity. In the meantime, MDA and oxidized DNA damage induced by a low level H2O2 decreased significantly after the trial. The reason accounted for the decrease of SOD activity after the trial needs to be further studied.