BACKGROUND: Down syndrome (DS) is the most common human chromosomal abnormality. It is characterized by mental retardation and several metabolic disturbances, including elevated oxidative stress, which may be causally linked. Treatment with dietary antioxidants has been suggested as a potential method to alleviate the oxidative damage and retardation of DS patients, but prior supplementation work has been equivocal.
AIM: To evaluate the effects of supplementation with antioxidants α-tocopherol and α-lipoic acid (ALA) on oxidative stress biomarkers in DS children.
METHODS: Ninety-three DS children aged 7-15 years from both sexes were randomly allocated to three groups: α-tocopherol (400 IU/day), ALA (100 mg/day) and placebo. The intervention period was 4 months. A healthy control group consisted 26 non-DS siblings. Serum thiobarbituric acid reactive substances (TBARS) and urinary 8-hydroxy-2'-deoxyguanosine (8OHdG) were used as biomarkers of oxidative stress.
RESULTS: DS children had greater levels of baseline oxidative stress than their siblings. Moreover, males had greater levels of 8OHdG than females (P<0.001) but there was no significant association between age and biomarkers of oxidative stress. Serum levels of TBARS did not change significantly over time, or relative to placebo. Although urinary 8OHdG concentrations decreased significantly in both α-tocopherol and ALA, groups compared with the baseline levels (P<0.001), mean final levels of urinary 8OHdG concentrations differed significantly only between α-tocopherol and placebo groups (P<0.01).
CONCLUSIONS: α-Tocopherol supplementation of the diets of DS children may attenuate oxidative stress at the DNA level.
We thank the families and children involved in our study. We also thank Dr Ahmad Reza Dorosti, Dr Reza Mahdavi, Dr Majid Hajifaraji, Dr Mehdi Hedaiati, Dr Mansoor Rezaei and Mrs Nasrin Shariatzadeh for their valuable contributions. This study was supported in part by National Nutrition and Food Technology Research Institute (NNFTRI). The α-tocopherol was a generous unrestricted gift from DSM Ltd (Netherlands). The trial was given ethical approval by the Ethics committee of the Tehran University of Medical Sciences and registered with the Iranian Clinical Trials Registry (registration number IRCT2013102215111N1).