Autism Spectrum Disorder: A Systematic Review About Nutritional Interventions

Abstract

Objective: To identify and analyze the scientific evidence of nutritional interventions performed in children and adolescents with Autism Spectrum Disorder. Data sources: A systematic review was conducted in the MEDLINE, Cochrane Library, Embase, LILACS, Google Scholar, PubMed, PsycINFO and Periódicos CAPES databases, using a search strategy to identify studies published between January 2003 and March 2018, in Portuguese, English and Spanish. Were included studies that described nutritional interventions in children and adolescents with autism spectrum disorders and assessed autistic behavior and/or gastrointestinal symptoms. We excluded other review articles and studies that did not include a control group in the research design. The studies were reviewed for descriptive information, and the quality of evidence was assessed through the GRADE system. Data synthesis: 18 studies were included in the review, being 16 randomized clinical trials, 1 case-control study and 1 open-label trial. As a result, the implementation of a gluten-free and casein-free diet was the most used intervention among the studies. Of the total, 10 studies showed a positive association of intervention with the evaluated results, while 8 did not find of a significant association. Conclusions: Although some authors report progress in the symptoms associated with autism in individuals with Autistic Spectrum Disorder undergoing nutritional interventions, there is little scientific evidence to support the use of nutritional supplements or dietary therapies in children and adolescents with autism.

Gastrointestinal Symptoms and Feeding Problems and Their Associations with Dietary Interventions, Food Supplement Use, and Behavioral Characteristics in a Sample of Children and Adolescents with Autism Spectrum Disorders

“…Evidence shows that in a sizeable proportion of individuals with ASD, the dietary intervention is a form of complementary and alternative medicine, i.e., practices and products that are not part of conventional Western medical care [ 51 ]. Implementation of a GFCF (gluten-free/casein-free) diet is the most used dietary intervention in ASD [ 23 , 52 ]. It is based on the “opioid excess hypothesis”.…”

“…It postulates that ASD results from a metabolic disorder in which opioid peptides produced by metabolism of gluten and casein pass through an abnormally permeable intestinal wall into blood, and exert harmful effects on processes in the brain [ 52 ]. Although scientific evidence shows some improvements in behavior on GFCF diet, there is insufficient data to support its broader use [ 23 , 53 ]. Several caregivers of our ASD subjects reported that they rather reduced than fully eliminated either gluten or casein, which raises questions about efficacy of such “partial” dietary treatment.…”

“…However, nutritional interventions in subjects with ASD are commonly introduced as an alternative treatment method of behavioral symptoms. Elimination diets are believed to reduce the deleterious effects caused by the improper metabolism of some food substances contributing to symptoms of ASD [ 23 ]. At present time there is no cure for ASD, and the available interventions for improving core symptoms are limited and often not satisfactory [ 3 , 24 ].…”

Efficacy of gluten- and casein-free diets on autism spectrum disorders in children

“…These 2 RCT demonstrated significant improvements in social isolation, and the overall ability to communicate and interact among ASD children. 31 However, the number of studies were insufficient to conclude the effect of a GCFD. The most recent review included studies between 2003 and 2019 with a total of 9 RCT with ages ranging between 2 to 18 years and the duration ranging from a week to 2 years.…”

Educational interventions used to improve the cognitive and social development of children and adolescents with autism

“…Autism Spectrum Disorder (ASD), considered one of the psychiatric or mental disorders, is characterized by an early onset neurological development disorder, impairment of social and communication skills. ASD covers autistic disorder (autism), Rett syndrome, Asperger's disorder, childhood disintegrative disorder, and pervasive developmental disorder not otherwise specified (Monteiro et al, 2020). ASD has a multifactorial cause, that is, genetic and environmental factors are involved.…”