Is there place for nutrition in the treatment of children with autism spectrum disorder?

Abstract

Autism is a neurodevelopmental disorder associated with significant social and financial burden. In recent years there has been an increasing interest in the use of dietary interventions as a complementary therapeutic option for these patients. The aim of this systematic review is to provide literature data about the effect of specific dietary interventions on clinical aspects of children with autism. For this reason, a literature search was conducted using Pubmed as the medical database source. No year-of-publication restriction was placed. Prospective studies conducted in pediatric populations and evaluating changes in clinical aspects of autism were considered. Types of dietary interventions evaluated in these studies included amino acids, fatty acids, vitamins/minerals, as well as specific diets (free of gluten/casein, ketogenic). The underlying mechanism of action of nutritional interventions in this pediatric population mainly includes regulation of neurotransmitters levels, as well as modification of gut microbiota. More specifically, Ν-acetylcysteine was shown to exert a beneficial effect on symptoms of irritability. This beneficial effect could be attributed to its antiglutamergic and antioxidative properties. With regards to fatty acids, it is known that they are involved in dopamine and serotonin metabolism, while low values of fatty acids have been reported in serum of patients with various neuropsychiatric disorders. However, their administration in children with autism did not make any difference in terms of clinical aspects of the disease. On the other hand, available literature data about effect of D-cycloserine, dimethylglycine and vitamins/minerals was either few or controversial. In parallel, we were able to identify in literature clinical studies showing a beneficial effect of gluten/casein-free and ketogenic diet on clinical phenotype of autism. Finally, it should be highlighted that no moderate or serious adverse events were reported in any of the above nutritional interventions. In general, current literature data is encouraging. Nevertheless, more randomized clinical trials are needed to more clearly confirm the effect of specific dietary interventions on clinical aspects of autism.