Zinc Deficiency in Autism: A Controlled Study

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterised by impaired socialisation and restricted and repetitive patterns of behaviour. Zinc deficiency has previously been reported in patients with ASD. A retrospective controlled trial of serum zinc levels in patients with ASD vs. non-ASD controls was undertaken to explore the potential presence of zinc deficiency in the ASD population. 72 patients with ASD were compared with 234 non-ASD controls. Serum zinc levels were compared between groups and correlations analysed for age, sex, supplement use and diet. Serum chromium and manganese levels were also compared between ASD and control groups to assess general micronutrient status. Further analysis was undertaken in the ASD group investigating potential correlations between serum zinc levels and immune function. 86% of patients with ASD were found to be zinc deficient versus 24% of the non-ASD control group. There was a mean difference of serum zinc levels between the ASD and non-ASD groups of 1·75 μmol/l (P<0·001, CI 1·2-2·1). There was no effect of age or sex on serum zinc levels in either the ASD or control groups. There was no significant difference in chromium or manganese levels between the ASD and control group. These results suggest zinc deficiency is likely to be common in ASD patients and is a potentially modifiable environmental factor associated with the condition. Zinc’s potential role in the aetio-pathogenesis and disease evolution is discussed, and the need to consider zinc status in patients with ASD is highlighted.