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

Exploring Dietary Interventions in Autism Spectrum Disorder

Autism spectrum disorder (ASD) involves social communication difficulties and repetitive behaviors, and it has a growing prevalence worldwide. Symptoms include cognitive impairments, gastrointestinal (GI) issues, feeding difficulties, and psychological problems. A significant concern in ASD is food selectivity, leading to nutrient deficiencies. Common GI issues in ASD, such as constipation and irritable bowel syndrome, stem from abnormal gut flora and immune system dysregulation. Sensory sensitivities and behavioral challenges exacerbate these problems, correlating with neurological symptom severity. Children with ASD also exhibit higher oxidative stress due to low antioxidant levels like glutathione. Therapeutic diets, including ketogenic, high-antioxidant, gluten-free and casein-free, and probiotic-rich diets, show potential in managing ASD symptoms like behavior, communication, GI issues, and oxidative stress, though the evidence is limited. Various studies have focused on different populations, but there is increasing concern about the impact among children. This review aims to highlight the food preferences of the ASD population, analyze the effect of the physicochemical and nutritional properties of foods on the selectivity in its consumption, GI problems, and antioxidant deficiencies in individuals with ASD, and evaluate the effectiveness of therapeutic diets, including diets rich in antioxidants, gluten-free and casein-free, ketogenic and essential fatty acids, and probiotic-rich diets in managing these challenges.

Impact of Gluten-Free and Casein-Free Diet on Behavioural Outcomes and Quality of Life of Autistic Children and Adolescents: A Scoping Review

BACKGROUND

Gluten- and casein-containing foods could aggravate the symptoms of children and adolescents with autism spectrum disorder (ASD), and subsequently impact their quality of life. However, there is a mixed opinion among researchers concerning the impact of alternative diet on reducing ASD symptoms.

OBJECTIVE

This scoping review aimed at examining the impact of the "gluten-free, casein-free" (GFCF) diet on health outcomes and the quality of life among autistic children and adolescents.

METHODS

A scoping review of the literature was performed following the Joanna Briggs Institute (JBI) guidelines. Four databases, including EbscoHost, Medline, CINAHL, and ProQuest, were used to obtain subject-specific studies relevant to the research question and published between July 2013 and March 2024. A comprehensive search using keywords such as "autism spectrum disorder", "gluten-free diet", and "casein-free diet" was conducted to obtain articles related to the research focus area. Only full-text, peer-reviewed, written in English articles were selected. Data extraction and data analysis were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses-extension to Scoping Review (PRISMA-ScR) protocol.

RESULTS

From the initial 586 studies, a total of 27 articles were included in the final analysis of the review. The thematic analysis included "GFCF diet and improvement of the core autistic symptoms", "the gut-brain link", "dietary interventions and autism", "possible side effects due to the GCFC diet", and "inconclusive studies and mixed opinions". A majority of the studies showed a positive effect of the GFCF diet on a variety of autistic symptoms, including positive changes in cognitive skills, behaviour, and gastrointestinal symptoms, while some showed conflicting evidence.

CONCLUSIONS

The currently available evidence on the impact of the "GFCF" diet on the quality of life of autistic children and adolescents may warrant potentially effective interventions for alleviating symptoms of autism spectrum disorders. However, this scoping review highlights the need for more research to provide more reliable evidence on the health outcomes and quality of life of ASD sufferers to guide practice.

Protocol for a randomized clinical trial comparing the efficacy of Structured Diet (SD) and Regular Therapy (RT) for adolescents with malnutrition having Autism Spectrum Disorder (ASD)

BACKGROUND

Autism spectrum disorders (ASD) have a lifelong impact on behavior, communication, cognitive function, education, physical functioning, and personal, or social life. Separate studies suggest, Therapeutic and dietary interventions are effective to some extent in managing these issues. No study integrated the nutrition and therapeutic approaches and examined the outcome on disease severity, overall health, and behavioral status in ASD. The proposed study is designed to evaluate the combined effect of regular therapy (RT) and structured diet (SD) compared to the usual diet (UD) for Adolescents with ASD.

METHODS

The proposed study will be a randomized clinical trial (RCT) with the assessor, therapist, and participants blinded to group allocation. Seventy ASD children with malnutrition will be enrolled in two different facilities of the Centre for the Rehabilitation of the Paralysed (CRP) between January 2023 and June 2023. Participants will be enrolled through a hospital-based randomization process from a population-based screening dataset, and with a concealed group allocation to either RT+ SD or RT+ UD group with a 1:1 ratio. The outcome measures are the Childhood Autism Rating Scale as per DSM-5 to determine the severity of ASD, Mid-upper arm circumference (MUAC), and BMI for nutritional status, and Gilliam Autism Rating Scale (GARS-2) to assess the behavioral status. Post-test will be performed after 12 weeks of intervention, and Follow-up will be taken after 6 months of post-test.

PERSPECTIVES

The result of the study will contribute to the provision of a comprehensive approach to malnourished Adolescents with ASD, and manage the issues related to the severity of ASD, stereotypical behavior, and anticipated health hazards.

CLINICAL TRIAL IDENTIFIER

CTRI/2022/11/047653.

Dietary Intake, Nutritional Status and Sensory Profile in Children with Autism Spectrum Disorder and Typical Development

Children with autism spectrum disorder (ASD) may consume a restricted diet, whether due to sensory sensitivities or an adherence to a gluten and casein free (GCF) diet. Our objective was to analyze dietary intake, nutritional status, and sensory profile in children with and without ASD. A descriptive, cross-sectional study was carried out in 65 children (3−12 years, ASD = 35, typical development (TD) = 30). Short Sensory Profile and food frequency questionnaires were applied. All participants were categorized into normal weight and excess weight, typical sensory performance (TP), and probable + definite difference (PD + DD); and ASD group into GCF dieters (ASD-diet) and non-dieters (ASD-no diet). Children with ASD had a higher intake (gr or ml/d) of vegetable drinks (p = 0.001), gluten-free cereals (p = 0.003), and a lower intake of fish (p < 0.001) than TD ones. The ASD group showed a lower score in total sensory profile score (p < 0.001) than TD group. In the ASD group, those who had PD + DD in their sensory profile consumed fewer dairies (p = 0.019), and more cereals (p = 0.036) and protein foods (p = 0.034) than those with TP. These findings confirm the need to consider the neurodevelopment, sensory profile, and type of diet to improve the ASD child’s nutrition. Further long-term research is needed to explore their impact on health.

The opioid excess theory in autism spectrum disorders - is it worth investigating further?

Autism spectrum disorders (ASD) are defined as neurodevelopmental disorders, which are highly variable in nature and do not form a uniform picture, either in terms of symptomatology or depth of the disturbance. Diagnosis of ASD is made for children who show signs of impairment in social interaction, communication and cognitive skills. The exact cause of autism spectrum disorders has not been determined to date. Although there is no cure for ASD, a variety interventions have been proposed. The most commonly used restrictive dietary intervention is the gluten-free casein-free diet (GFCF), which is based on the opioid excess theory. This paper summarizes and discusses research on the core elements of the opioid excess theory in ASD: increased levels of opioid peptides in body fluids in ASD patients, increased intestinal permeability, altered peptidase activity and the effectiveness of GFCF diet in alleviating symptoms of ASD. Furthermore, we discuss the difficulties and their causes in conducting research with ASD patients. The assumptions of the opioid excess theory have neither been definitively confirmed nor disproved. Research in this area should continue, taking into account the highest possible quality standards and the specific needs and abilities of patients with ASD and their families.

Dietary Patterns, Eating Behavior, and Nutrient Intakes of Spanish Preschool Children with Autism Spectrum Disorders

Eating behavior problems are characteristic of children with autism spectrum disorders (ASD) with a highly restricted range of food choices, which may pose an associated risk of nutritional problems. Hence, detailed knowledge of the dietary patterns (DPs) and nutrient intakes of ASD patients is necessary to carry out intervention strategies if required. The present study aimed to determine the DPs and macro-and micronutrient intakes in a sample of Spanish preschool children with ASD compared to typically developing control children. Fifty-four children with ASD (two to six years of age) diagnosed with ASD according to the Diagnostic Manual-5 criteria), and a control group of 57 typically developing children of similar ages were recruited. A validated food frequency questionnaire was used, and the intake of energy and nutrients was estimated through three non-consecutive 24-h dietary registrations. DPs were assessed using principal component analysis and hierarchical clustering analysis. Children with ASD exhibited a DP characterized by high energy and fat intakes and a low intake of vegetables and fruits. Likewise, meat intake of any type, both lean and fatty, was associated with higher consumption of fish and dietary fat. Furthermore, the increased consumption of dairy products was associated with increased consumption of cereals and pasta. In addition, they had frequent consumption of manufactured products with poor nutritional quality, e.g., beverages, sweets, snacks and bakery products. The percentages of children with ASD complying with the adequacy of nutrient intakes were higher for energy, saturated fat, calcium, and vitamin C, and lower for iron, iodine, and vitamins of group B when compared with control children. In conclusion, this study emphasizes the need to assess the DPs and nutrient intakes of children with ASD to correct their alterations and discard some potential nutritional diseases.