The effect of dietary supplements on clinical aspects of autism spectrum disorder: A systematic review of the literature.

BACKGROUND: Autism spectrum disorder is associated with significant social and financial burden and no definite treatment for this entity has been identified, yet. In recent years there has been an increasing interest in the use of dietary interventions as a complementary therapeutic option for these patients.

OBJECTIVE: The aim of this systematic review is to provide high evidence level literature data about the effect of dietary supplements on clinical aspects of children with autism.

METHODS: A comprehensive literature search was conducted using Pubmed as the medical database source. Randomized controlled trials conducted in pediatric populations and including measures of clinical outcomes were considered.

RESULTS: A total of 17 eligible prospective studies were selected. Types of dietary supplements evaluated in these studies included amino acids, fatty acids and vitamins/minerals. N-acetylcysteine was shown to exert a beneficial effect on symptoms of irritability. On the other hand, literature data about the efficacy of d-cycloserine and pyridoxine-magnesium supplements was controversial. No significant effect was identified for fatty acids, N,N-dimethylglycine and inositol. Literature data about ascorbic acid and methyl B12 was few, although some encouraging results were found. No serious adverse events were reported in the vast majority of the studies, while the prevalence of adverse reactions was similar between treatment and placebo groups.

CONCLUSIONS: The use of dietary supplements in children with autism seems to be a safe practice with encouraging data about their clinical efficacy. More studies are needed to further investigate this issue.