Effects of consumption of selenium biofortified milk on antioxidant and inflammatory biomarkers in children with autism spectrum disorder: A controlled, single-blind intervention study

Children with Autism Spectrum Disorder (ASD) often exhibit food selectivity, which may be associated with inadequate Selenium (Se) intake and imbalances in serum levels of enzymatic and non-enzymatic antioxidants as well as inflammatory cytokines. Several studies suggest an association between autism and increased oxidative stress. However, clinical studies in this population remain scarce due to methodological challenges, as do studies assessing Se status and the effects of Se biofortified foods. In this context, the present study aimed to quantify serum levels of Se, zinc (Zn), vitamin E (VitE), antioxidant enzymes, and pro-inflammatory cytokines in children with ASD before and after dietary intervention with Se biofortified cow's milk. Seventeen children with ASD aged between 3 and 10 years were selected and allocated into a conventional milk ( n = 8), and the Se biofortification group ( n = 9), which received cow's milk containing 190 μg/L of Se for 12 weeks (84 days). Serum levels of enzymatic and non-enzymatic antioxidants and gene expression of pro-inflammatory cytokines were measured at baseline and the end of the study. Following the intervention, serum Se levels were significantly higher in the biofortified group (62.97 vs 102.82 μg/dL, p < 0.05). No significant differences were observed in antioxidant enzyme expression; although not statistically significant, greater glutathione peroxidase 1 (GPx1) and catalase (CAT) levels were observed post-intervention, as well as a tendency toward lower VitE and Zn levels. Among the measured pro-inflammatory cytokines, only interleukin 8 (IL-8) significantly increased. Tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ) showed a positive correlation with antioxidant enzymes ( p < 0.05). These findings suggest that Se biofortification of milk may serve as a potential nutritional strategy for children with ASD.