A systematic review and meta-analysis of the benefits of a gluten-free diet and/or casein-free diet for children with autism spectrum disorder

Nutritional Approaches in Autism Spectrum Disorder: A Scoping Review

PURPOSE OF REVIEW

This review was conducted to discuss the etiology of autism in the light of current information, to draw attention to the fact that defects in different biological mechanisms cause autism, and to examine the effectiveness of dietary interventions and supplements in relieving ASD symptoms.

RECENT FINDINGS

Autism spectrum disorder (ASD) is an extremely heterogeneous condition characterized by delays in reciprocal social interaction and communication skills, stereotyped behaviors, and a narrowed range of interests and limited activities. Comorbid conditions such as cognitive impairment, epilepsy, psychiatric diseases, and behavioral symptoms such as impaired social communication, repetitive behaviors, lack of interest in the environment, nutritional disorders, gastrointestinal diseases and abnormal (dysbiotic) states, sleep disorders, and dysmorphism are frequently encountered in individuals with ASD. Although nutrition is one of the environmental factors affecting ASD, it can also be effective in alleviating the behavioral and gastrointestinal symptoms of ASD. Various dietary models (GFCF diet, low glycemic index diet, ketogenic diet, specific carbohydrate diet, Mediterranean diet, GAPS, Feingold, Candida body ecology, allergy elimination diets, etc.) and supplements (vitamin D, polyunsaturated fatty acids, probiotics and prebiotics, phytochemicals) can be used to alleviate symptoms in individuals with ASD. The effectiveness and reliability of dietary interventions in individuals with ASD are a matter of significant debate, and the evidence for these practices is limited. Furthermore, there is no consensus on establishing an ideal nutritional model for individuals with ASD.

The Gut-Brain-Microbiota Connection and Its Role in Autism Spectrum Disorders

Autism spectrum disorder (ASD) is a group of complex neurodevelopmental conditions with a heterogeneous and multifactorial etiology that is not yet fully understood. Among the various factors that may contribute to ASD development, alterations in the gut microbiota have been increasingly recognized. Microorganisms in the gastrointestinal tract play a crucial role in the gut-brain axis (GBA), affecting nervous system development and behavior. Dysbiosis, or an imbalance in the microbiota, has been linked to both behavioral and gastrointestinal (GI) symptoms in individuals with ASD. The microbiota interacts with the central nervous system through mechanisms such as the production of short-chain fatty acids (SCFAs), the regulation of neurotransmitters, and immune system modulation. Alterations in its composition, including reduced diversity or an overabundance of specific bacterial taxa, have been associated with the severity of ASD symptoms. Dietary modifications, such as gluten-free or antioxidant-rich diets, have shown potential for improving gut health and alleviating behavioral symptoms. Probiotics, with their anti-inflammatory properties, may support neural health and reduce neuroinflammation. Fecal microbiota transplantation (FMT) is being considered, particularly for individuals with persistent GI symptoms. It has shown promising outcomes in enhancing microbial diversity and mitigating GI and behavioral symptoms. However, its limitations should be considered, as discussed in this narrative review. Further research is essential to better understand the long-term effects and safety of these therapies. Emphasizing the importance of patient stratification and phenotype characterization is crucial for developing personalized treatment strategies that account for individual microbiota profiles, genetic predispositions, and coexisting conditions. This approach could lead to more effective interventions for individuals with ASD. Recent findings suggest that gut microbiota may play a key role in innovative therapeutic approaches to ASD management.

Critical Appraisal of Systematic Reviews Assessing Gut Microbiota and Effect of Probiotic Supplementation in Children with ASD-An Umbrella Review

Given the significance of gut microbiota in autism spectrum disorder (ASD), we aimed to assess the quality of systematic reviews (SRs) of studies assessing gut microbiota and effects of probiotic supplementation in children with ASD. PubMed, EMBASE, PsycINFO, Medline, and Cochrane databases were searched from inception to November 2024. We included SRs of randomised or non-randomized studies reporting on gut microbiota or effects of probiotics in children with ASD. A total of 48 SRs (probiotics: 21, gut microbiota: 27) were included. The median (IQR) number of studies and participants was 7 (5) and 328 (362), respectively, for SRs of probiotic intervention studies and 18 (18) and 1083 (1201), respectively, for SRs of gut microbiota studies in children with ASD. The quality of included SRs was low (probiotics: 12, gut microbiota: 14) to critically low (probiotics: 9, gut microbiota: 13) due to lack of reporting of critical items including prior registration, deviation from protocol, and risk of bias assessment of included studies. Assuring robust methodology and reporting of future studies is important for generating robust evidence in this field.

The Role of Nutrition, Oxidative Stress, and Trace Elements in the Pathophysiology of Autism Spectrum Disorders

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by deficits in social communication and interaction, alongside repetitive behaviors, and atypical sensory-motor patterns. The growing prevalence of ASD has driven substantial advancements in research aimed at understanding its etiology, preventing its onset, and mitigating its impact. This ongoing effort necessitates continuous updates to the body of knowledge and the identification of previously unexplored factors. The present study addresses this need by examining the roles of nutrition, oxidative stress, and trace elements in the pathophysiology of ASD. In this review, an overview is provided of the key dietary recommendations for individuals with ASD, including gluten-free and casein-free (GFCF) diets, ketogenic diets (KDs), and other nutritional interventions. Furthermore, it explores the involvement of oxidative stress in ASD and highlights the significance of trace elements in maintaining neuropsychiatric health. The impact of these factors on molecular and cellular mechanisms was discussed, alongside therapeutic strategies and their efficacy in managing ASD.

Pain, dietary habits and physical activity of children with developmental disabilities in Croatia, North Macedonia and Serbia: a cross-sectional study

BACKGROUND

Multiple studies have shown that children with developmental disabilities (CDD) often live with unrecognized and untreated pain, consume inadequate diet and have inadequate levels of physical activity. This study aimed to analyze pain, dietary habits and physical activity of CDD in Croatia, North Macedonia and Serbia.

METHODS

A cross-sectional study was conducted in Croatia, North Macedonia and Serbia in March-April 2023 within the Erasmus+ SynergyEd project. The study included parents and caregivers of CDD. Data were collected via online survey.

RESULTS

We included 954 participants from Croatia (N=543; 57%), North Macedonia (N=205; 21%) and Serbia (N=206; 22%). Participants reported that 16% of children suffered from chronic pain related to their condition. The main findings of our study are that chronic pain is prevalent in CDD (16%). Almost half (48%) of participants avoid certain foods for their children. The majority of children (86%) were not on a special diet. Among those that were on a special diet, they were most commonly (60%) on a gluten-free diet. Most (54%) participants stated that their children used nutritional supplements. Less than half participants (45%) stated that the child is involved in some kind of physical activity. Only 17% of CDD engaged in physical activities 5 h or more per week.

CONCLUSION

Our findings indicate that chronic pain, inadequate dietary patterns and insufficient physical activity are common in CDD from Croatia, Macedonia and Serbia. Education of parents and caregivers can mitigate their use of interventions that have not been proven effective, such as for example the use of gluten-free diets in CDD.

An Update on Microbial Interventions in Autism Spectrum Disorder with Gastrointestinal Symptoms

In the United States, autism spectrum disorder (ASD) affects 1 in 33 children and is characterized by atypical social interactions, communication difficulties, and intense, restricted interests. Microbial dysbiosis in the gastrointestinal (GI) tract is frequently observed in individuals with ASD, potentially contributing to behavioral manifestations and correlating with worsening severity. Moreover, dysbiosis may contribute to the increased prevalence of GI comorbidities in the ASD population and exacerbate immune dysregulation, further worsening dysbiosis. Over the past 25 years, research on the impact of microbial manipulation on ASD outcomes has gained substantial interest. Various approaches to microbial manipulation have been preclinically and clinically tested, including antibiotic treatment, dietary modifications, prebiotics, probiotics, and fecal microbiota transplantation. Each method has shown varying degrees of success in reducing the severity of ASD behaviors and/or GI symptoms and varying long-term efficacy. In this review, we discuss these microbiome manipulation methods and their outcomes. We also discuss potential microbiome manipulation early in life, as this is a critical period for neurodevelopment.

Maternal insulinemic and inflammatory dietary patterns and risk of child neurodevelopmental delay

PURPOSE

Our aim was to assess the risk of higher insulinemic, inflammatory, and hyperglycemia potential in the diet during pregnancy with child neurodevelopmental delay.

METHODS

We enrolled 7,438 pregnant women participating in a prospective cohort study. The food frequency questionnaire was used to evaluate the empirical dietary index for hyperinsulinemia (EDIH), empirical dietary inflammatory pattern (EDIP), glycemic index (GI), and glycemic load (GL) during mid-pregnancy. Child neurodevelopmental assessment was conducted at 6-36 months postpartum using the Denver Developmental Screening Test-II (DDST-II) scale, and the Gesell Developmental Diagnosis Scale (GDDS) was administered to assess children who did not meet the criteria for passing the DDST-II screening.

RESULTS

We documented 540 incident child neurodevelopmental delay cases over 7,438 pregnant women (median follow-up: 2 years). Pregnant women exhibiting the high levels of hyperinsulinemic or proinflammatory components, or GI encountered an elevated risk of child neurodevelopmental delay; HRs (95% CI) comparing highest to lowest dietary index quintiles were EDIH 1.48 (1.07,2.04; P trend = 0.017), EDIP 1.39 (1.05,1.84; P trend = 0.019) and GI 1.36 (1.02,1.81; P trend = 0.038). In sex-stratified analyses, these results remained significant only in boys (P trend = 0.018 for EDIH, P trend = 0.028 for EDIP, P trend = 0.029 for GI). The performance of combined model of EDIH and EDIP for boys is comparable to that of the combined model of EDIH, EDIP, and GI to assess the risk of neurodevelopmental delay (AUC [area under curve] 0.801 vs. AUC 0.830). Both values are higher than the AUC values achieved by models using either set of indicators individually.

CONCLUSION

Our findings suggest that maternal consumption of diets with high insulinemic, inflammatory, or glycemic index properties may be associated with neurodevelopmental delays in children, particularly in boys. Higher insulinemic and inflammatory potentials in maternal diet may forecast neurodevelopmental delay in boys.

UHT Cow's Milk Supplementation Affects Cell Niches and Functions of the Gut-Brain Axis in BALB/c Mice

BACKGROUND/OBJECTIVES

Cow's milk is a bioactive cocktail with essential nutritional factors that is widely consumed during early childhood development. However, it has been associated with allergic responses and immune cell activation. Here, we investigate whether cow's milk consumption regulates gut-brain axis functions and affects patterns of behaviors in BALB/c mice, previously described by present low sociability, significant stereotypes, and restricted interest features. The major objectives consist of to investigate cow's milk supplementation as possible triggers interfering with cellular niches of the gut-brain axis and behavioral patterns.

METHODS

Male BALB/c at 6 weeks were randomly divided into two groups, one supplemented with cow's milk processed at ultra-high temperature (UHT) and another group receiving water (controls) three times per day (200 μL per dose) for one week.

RESULTS

Milk consumption disturbed histological compartments of the small intestine, including niches of KI67+-proliferating cells and CD138+ Ig-secreting plasma cells. In the liver, milk intake was associated with pro-inflammatory responses, oxidative stress, and atypical glycogen distribution. Milk-supplemented mice showed significant increase in granulocytes (CD11b+SSChigh cells) and CD4+ T cells in the blood. These mice also had neuroinflammatory signals, including an enhanced number of cortical Iba-1+ microglial cells in the brain and significant cerebellar expression of nitric oxide synthase 2 by Purkinje cells. These phenotypes and tissue disorders in milk-supplemented mice were associated with atypical behaviors, including low sociability, high restricted interest, and severe stereotypies. Moreover, synaptic niches were also disturbed after milk consumption, and Shank-3+ and Drebrin+ post-synaptic cells were significantly reduced in the brain of these mice.

CONCLUSIONS

Together, these data suggest that milk consumption interfered with the gut-brain axis in BALB/c mice and increased atypical behaviors, at least in part, linked to synapse dysfunctions, neuroinflammation, and oxidative stress regulation.

The Role of Dietary Peptides Gluten and Casein in the Development of Autism Spectrum Disorder: Biochemical Perspectives

This paper examines the role of dietary peptides gluten and casein in modulating brain function in individuals with autism spectrum disorder (ASD) from a biochemical perspective. Neurotransmitter systems and neural networks are crucial for brain function, and alterations at the biochemical level can contribute to the characteristic symptoms and behaviors of ASD. The paper explores how dietary peptides influence neurotransmitter systems and neural networks, highlighting their potential as interventions to improve brain function in ASD. The evidence suggests that dietary peptides can impact neurotransmitter synthesis, release, and receptor interactions, disrupting the balance of neurotransmitter systems and affecting neural network function. The findings underscore the potential of dietary interventions in modulating brain function in ASD and call for further research to elucidate the underlying mechanisms and optimize clinical practice. Considering individual dietary sensitivities and preferences, personalized dietary approaches may be necessary for optimal outcomes. Dietary interventions' timing, duration, and integration with other evidence-based treatments are crucial considerations. Safety considerations and regular monitoring are important to ensure the implementation of dietary interventions safely and effectively.

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.

Dietary Factors Impact Developmental Trajectories in Young Autistic Children

PURPOSE

The purpose of this research was to investigate the impact of dietary factors on developmental trajectories in young autistic children.

METHODS

A gluten-free and casein-free diets, as well as six types of food (meat and eggs, vegetables, uncooked vegetables, sweets, bread, and "white soft bread that never molds") were investigated observationally for up to three years in 5,553 children 2 to 5 years of age via parent-report measures completed within a mobile application. Children had a parent-reported diagnosis of Autism Spectrum Disorder (ASD); 78% were males; the majority of participants resided in the USA. Outcome was monitored on five orthogonal subscales: Language Comprehension, Expressive Language, Sociability, Sensory Awareness, and Health, assessed by the Autism Treatment Evaluation Checklist (ATEC) (Rimland & Edelson, 1999) and Mental Synthesis Evaluation Checklist (MSEC) (Arnold & Vyshedskiy, 2022; Braverman et al., 2018).

RESULTS

Consumption of fast-acting carbohydrates - sweets, bread, and "white soft bread that never molds" - was associated with a significant and a consistent Health subscale score decline. On the contrary, a gluten-free diet, as well as consumption of meat, eggs, and vegetables were associated with a significant and consistent improvement in the Language Comprehension score. Consumption of meat and eggs was also associated with a significant and consistent improvement in the Sensory Awareness score.

CONCLUSION

The results of this study demonstrate a strong correlation between a diet and developmental trajectories and suggest possible dietary interventions for young autistic children.

Dietary interventions in autism: a critical appraisal and commentary on the findings of a systematic review

An estimated 1% of the global population is believed to be autistic. Clinical focus is often on interventions that target social functioning, sensory processing and communication. Dietary interventions are often explored as a means of targeting these core symptoms. However, research findings are often inconclusive due to small sample sizes. This commentary critically examines a meta-analysis focused on dietary interventions - including omega-3, vitamins, and other supplements - in the treatment of autism. It evaluates the study's findings and contextualizes their implications for neurological nursing practice.

The Role of Dietary Patterns and Nutritional Supplements in the Management of Mental Disorders in Children and Adolescents: An Umbrella Review of Meta-Analyses: Le rôle des habitudes alimentaires et des suppléments nutritionnels dans la prise en charge des troubles mentaux chez les enfants et les adolescents : une méta-revue de méta-analyses

OBJECTIVE

In recent years, the relationship between nutrition and mental health has gained considerable interest. We identified, synthesized, and appraised all meta--analyses of randomized controlled trials (RCTs) and observational studies reporting on the efficacy of dietary patterns and nutrient supplements in the prevention and treatment of mental disorders in children and adolescents.

METHODS

Systematic research in MEDLINE, PsycINFO, Scopus, and Cochrane Database of Systematic Reviews was completed on 8 January 2024.

RESULTS

Our research found 24 meta-analyses: 14 on RCTs, 8 on observational studies, and 2 combining both. Emerging evidence suggests that omega-3, in particular eicosapentaenoic acid, and Vitamin D may have adjunctive benefits in the treatment of attention deficit hyperactivity disorder (ADHD), while no evidence was found for autism spectrum disorder (ASD). Observational data also indicated that prenatal folic acid supplementation (>400 μg daily) was associated with a reduced risk of ASD in offspring. In terms of dietary habits, several meta-analyses of observational data revealed that healthy dietary patterns (rich in fruits, vegetables, and fibre, low in saturated fats) during the prenatal period, childhood, and adolescence were linked to a significantly reduced risk of internalizing disorders and externalizing disorders. Conversely, unhealthy dietary habits (high in sugars, saturated animal fats, and industrial foods, low in fruits, vegetables, and fibre) are associated with an elevated risk of these mental health issues. However, the number of available studies on dietary interventions for the treatment of depression, ASD, and ADHD was limited, and the results obtained were either nonsignificant or contradictory.

CONCLUSION

Our findings emphasize the need to establish clear causal relationships between dietary habits and the risk of mental illness in children and adolescents. Moreover, further investigation of the benefits observed with some nutrient supplements (such as omega-3 and vitamin D for ADHD) through larger-scale RCTs is imperative to establish more robust conclusions.

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.

Reversal of Autism Symptoms among Dizygotic Twins through a Personalized Lifestyle and Environmental Modification Approach: A Case Report and Review of the Literature

The prevalence of autism has been increasing at an alarming rate. Even accounting for the expansion of autism spectrum disorder diagnostic (ASD) criteria throughout the 1990's, there has been an over 300% increase in ASD prevalence since the year 2000. The often debilitating personal, familial, and societal sequelae of autism are generally believed to be lifelong. However, there have been several encouraging case reports demonstrating the reversal of autism diagnoses, with a therapeutic focus on addressing the environmental and modifiable lifestyle factors believed to be largely underlying the condition. This case report describes the reversal of autism symptoms among dizygotic, female twin toddlers and provides a review of related literature describing associations between modifiable lifestyle factors, environmental exposures, and various clinical approaches to treating autism. The twins were diagnosed with Level 3 severity ASD "requiring very substantial support" at approximately 20 months of age following concerns of limited verbal and non-verbal communication, repetitive behaviors, rigidity around transitions, and extensive gastrointestinal symptoms, among other common symptoms. A parent-driven, multidisciplinary, therapeutic intervention involving a variety of licensed clinicians focusing primarily on addressing environmental and modifiable lifestyle factors was personalized to each of the twin's symptoms, labs, and other outcome measures. Dramatic improvements were noted within several months in most domains of the twins' symptoms, which manifested in reductions of Autism Treatment Evaluation Checklist (ATEC) scores from 76 to 32 in one of the twins and from 43 to 4 in the other twin. The improvement in symptoms and ATEC scores has remained relatively stable for six months at last assessment. While prospective studies are required, this case offers further encouraging evidence of ASD reversal through a personalized, multidisciplinary approach focusing predominantly on addressing modifiable environmental and lifestyle risk factors.

The Effect of a Casein and Gluten-Free Diet on the Epigenetic Characteristics of FoxP3 in Patients With Hashimoto's Thyroiditis

Background Hashimoto's thyroiditis (HT) is an autoimmune thyroid disease characterized by inflammation and dysfunction of the thyroid gland, resulting in hypothyroidism, it results in impaired thyroid hormone generation and mimics hypothyroidism. The disease involves complex interactions among genetic, environmental, and epigenetic factors, particularly affecting the regulation of T regulatory (Treg) cells, including CD4 + foxp3 + T cells. Treg cells, defined as CD4 + T cells, rely on the expression of the foxp3 transcription factor, which is crucial for their development and differentiation. Disruptions in this regulation can lead to immune dysregulation and potential proinflammatory responses. The study focuses on investigating the impact of dietary patterns on the epigenetic changes in the foxp3 gene, a key player in the development of HT. The primary aim was to evaluate how eliminating gluten and casein proteins from dietary regimens may influence the methylation levels of the foxp3 gene, considering the potential link between these dietary components and the triggering of autoimmune diseases. Methods An epigenetic analysis of the foxp3 gene in HT patients who were strictly following a dietary plan compared with the control group. For the epigenetic study, a methylation analysis experiment was conducted.  Results Our findings revealed a notable reduction in foxp3 gene methylation levels among HT patients who adhered to a diet excluding casein and gluten. The control maintained normal dietary guidelines and showed no significant alterations in methylation levels. Discussion The laboratory values showed a decrease in methylation levels of the foxp3 gene, with statistical significance indicated as *p<0.005, **p<0.001, ***p<0.0001, suggesting a potential enhancement in its expression which could have profound implications for immune system regulation. Disruptions in the foxp3 pathway are crucial in the development of autoimmune disorders, where altered activity hinders the regulation of T cell (Treg) development, ultimately contributing to conditions like HT disease. These findings imply that nutritional interventions, especially for individuals with HT, could potentially be a strategy for mitigating autoimmunity through epigenetic mechanisms.

Autism spectrum disorders and the gastrointestinal tract: insights into mechanisms and clinical relevance

Autism spectrum disorders (ASDs) are recognized as central neurodevelopmental disorders diagnosed by impairments in social interactions, communication and repetitive behaviours. The recognition of ASD as a central nervous system (CNS)-mediated neurobehavioural disorder has led most of the research in ASD to be focused on the CNS. However, gastrointestinal function is also likely to be affected owing to the neural mechanistic nature of ASD and the nervous system in the gastrointestinal tract (enteric nervous system). Thus, it is unsurprising that gastrointestinal disorders, particularly constipation, diarrhoea and abdominal pain, are highly comorbid in individuals with ASD. Gastrointestinal problems have also been repeatedly associated with increased severity of the core symptoms diagnostic of ASD and other centrally mediated comorbid conditions, including psychiatric issues, irritability, rigid-compulsive behaviours and aggression. Despite the high prevalence of gastrointestinal dysfunction in ASD and its associated behavioural comorbidities, the specific links between these two conditions have not been clearly delineated, and current data linking ASD to gastrointestinal dysfunction have not been extensively reviewed. This Review outlines the established and emerging clinical and preclinical evidence that emphasizes the gut as a novel mechanistic and potential therapeutic target for individuals with ASD.

Branched-chain amino acids as adjunctive-alternative treatment in patients with autism: a pilot study

The branched-chain amino acid (BCAA) is a group of essential amino acids that are involved in maintaining the energy balance of a human being as well as the homoeostasis of GABAergic, glutamatergic, serotonergic and dopaminergic systems. Disruption of these systems has been associated with the pathophysiology of autism while low levels of these amino acids have been discovered in patients with autism. A pilot open-label, prospective, follow-up study of the use of BCAA in children with autistic behaviour was carried out. Fifty-five children between the ages of 6 and 18 participated in the study from May 2015 to May 2018. We used a carbohydrate-free BCAA-powdered mixture containing 45·5 g of leucine, 30 g of isoleucine and 24·5 g of valine in a daily dose of 0·4 g/kg of body weight which was administered every morning. Following the initiation of BCAA administration, children were submitted to a monthly psychological examination. Beyond the 4-week mark, BCAA were given to thirty-two people (58·18 %). Six of them (10·9 %) discontinued after 4-10 weeks owing to lack of improvement. The remaining twenty-six children (47·27 %) who took BCAA for longer than 10 weeks displayed improved social behaviour and interactions, as well as improvements in their speech, cooperation, stereotypy and, principally, their hyperactivity. There were no adverse reactions reported during the course of the treatment. Although these data are preliminary, there is some evidence that BCAA could be used as adjunctive treatment to conventional therapeutic methods for the management of autism.

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.

Ratings of the Effectiveness of 13 Therapeutic Diets for Autism Spectrum Disorder: Results of a National Survey

This study presents the results of the effectiveness of 13 therapeutic diets for autism spectrum disorder from 818 participants of a national survey, including benefits, adverse effects, and symptom improvements. The average Overall Benefit of diets was 2.36 (0 = no benefit, 4 = great benefit), which was substantially higher than for nutraceuticals (1.59/4.0) and psychiatric/seizure medications (1.39/4.0), p < 0.001. The average Overall Adverse Effects of diets was significantly lower than psychiatric/seizure medications (0.10 vs. 0.93, p < 0.001) and similar to nutraceuticals (0.16). Autism severity decreased slightly over time in participants who used diet vs. increasing slightly in those that did not (p < 0.001). Healthy and Feingold diets were the two top-rated diets by Overall Benefit; the ketogenic diet was the highest for nine symptoms (though had fewer respondents); and the gluten-free/casein-free diet was among the top for overall symptom improvements. Different diets were reported to affect different symptoms, suggesting that an individual's symptoms could be used to guide which diet(s) may be the most effective. The results suggest that therapeutic diets can be safe and effective interventions for improving some ASD-related symptoms with few adverse effects. We recommend therapeutic diets that include healthy foods and exclude problematic foods. Therapeutic diets are inexpensive treatments that we recommend for consideration by most people with ASD.

Role of gastrointestinal health in managing children with autism spectrum disorder

Children with autism spectrum disorders (ASD) or autism are more prone to gastrointestinal (GI) disorders than the general population. These disorders can significantly affect their health, learning, and development due to various factors such as genetics, environment, and behavior. The causes of GI disorders in children with ASD can include gut dysbiosis, immune dysfunction, food sensitivities, digestive enzyme deficiencies, and sensory processing differences. Many studies suggest that numerous children with ASD experience GI problems, and effective management is crucial. Diagnosing autism is typically done through genetic, neurological, functional, and behavioral assessments and observations, while GI tests are not consistently reliable. Some GI tests may increase the risk of developing ASD or exacerbating symptoms. Addressing GI issues in individuals with ASD can improve their overall well-being, leading to better behavior, cognitive function, and educational abilities. Proper management can improve digestion, nutrient absorption, and appetite by relieving physical discomfort and pain. Alleviating GI symptoms can improve sleep patterns, increase energy levels, and contribute to a general sense of well-being, ultimately leading to a better quality of life for the individual and improved family dynamics. The primary goal of GI interventions is to improve nutritional status, reduce symptom severity, promote a balanced mood, and increase patient independence.

A Spectrum of Solutions: Unveiling Non-Pharmacological Approaches to Manage Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a developmental disorder that causes difficulty while socializing and communicating and the performance of stereotyped behavior. ASD is thought to have a variety of causes when accompanied by genetic disorders and environmental variables together, resulting in abnormalities in the brain. A steep rise in ASD has been seen regardless of the numerous behavioral and pharmaceutical therapeutic techniques. Therefore, using complementary and alternative therapies to treat autism could be very significant. Thus, this review is completely focused on non-pharmacological therapeutic interventions which include different diets, supplements, antioxidants, hormones, vitamins and minerals to manage ASD. Additionally, we also focus on complementary and alternative medicine (CAM) therapies, herbal remedies, camel milk and cannabiodiol. Additionally, we concentrate on how palatable phytonutrients provide a fresh glimmer of hope in this situation. Moreover, in addition to phytochemicals/nutraceuticals, it also focuses on various microbiomes, i.e., gut, oral, and vaginal. Therefore, the current comprehensive review opens a new avenue for managing autistic patients through non-pharmacological intervention.

Understanding the link between gut microbiota, dietary intake, and nutritional status in children with autism and typical development

Background

Gut microbiota plays a potential role in human health and different disorders such as autism spectrum disorder (ASD). Therefore, we analyzed gut bacteria composition in children with ASD and typical development (TD), and its relationship with nutritional status and dietary intake.

Methods

A descriptive cross-sectional study was carried out in 3- to 12-year-old children (ASD = 30, TD = 28). Dietary intake (applying food frequency questionnaires) and body mass index-for-age (expressed in z-score) were determined. Children were divided into normal weight and excess weight (risk of overweight + overweight + obesity), and the ASD group was categorized into gluten- and casein-free diet (ASD-diet) or no diet (ASD-no diet). The relative abundance of gut bacteria was analyzed in fecal samples by 16S rRNA sequencing.

Results

Children with excess weight had lower Roseburia than normal weight. Fewer Bifidobacterium longum and higher Clostridium glycolicum were found in the ASD group compared with TD one. Participants with excess weight and ASD had lower Roseburia and Faecalibacterium prausnitzii and higher Eubacterium ventricosum and Flavonifractor plautii than the TD group with the same nutritional status. Positive and negative associations were found between the bacteria genus and species, and the intake of dairy, vegetable drinks, cereals with and without gluten, food source of proteins, fish, food source of fat, and coconut oil, in unadjusted models and after adjustment for age, diet/no diet, ASD/TD.

Conclusion

Significant differences in microbial community composition were found between children with ASD and TD, considering their nutritional status and dietary intake.

Dysregulated phosphate metabolism in autism spectrum disorder: associations and insights for future research

Studies of autism spectrum disorder (ASD) related to exposure to toxic levels of dietary phosphate are lacking. Phosphate toxicity from dysregulated phosphate metabolism can negatively impact almost every major organ system of the body, including the central nervous system. The present paper used a grounded theory-literature review method to synthesise associations of dysregulated phosphate metabolism with the aetiology of ASD. Cell signalling in autism has been linked to an altered balance between phosphoinositide kinases, which phosphorylate proteins, and the counteracting effect of phosphatases in neuronal membranes. Glial cell overgrowth in the developing ASD brain can lead to disturbances in neuro-circuitry, neuroinflammation and immune responses which are potentially related to excessive inorganic phosphate. The rise in ASD prevalence has been suggested to originate in changes to the gut microbiome from increasing consumption of additives in processed food, including phosphate additives. Ketogenic diets and dietary patterns that eliminate casein also reduce phosphate intake, which may account for many of the suggested benefits of these diets in children with ASD. Dysregulated phosphate metabolism is causatively linked to comorbid conditions associated with ASD such as cancer, tuberous sclerosis, mitochondrial dysfunction, diabetes, epilepsy, obesity, chronic kidney disease, tauopathy, cardiovascular disease and bone mineral disorders. Associations and proposals presented in this paper offer novel insights and directions for future research linking the aetiology of ASD with dysregulated phosphate metabolism and phosphate toxicity from excessive dietary phosphorus intake.

The importance of comprehensive support based on the three pillars of exercise, nutrition, and sleep for improving core symptoms of autism spectrum disorders

Autism spectrum disorder (ASD) is classified as a neurodevelopmental disorder. The Diagnostic and Statistical Manual of Mental Disorders (DSM)-V, which first described ASD, lists persistent deficits in social communication and interrelationships, as well as limited and recurrent modes of behavior, interests, and activities as diagnostic items. Until recently, understanding the pathophysiology of ASD has been mostly from a neurophysiological perspective, and interventions have been mostly behavioral and psychological. In recent years, however, it has become clear that ASD also affects many bodily systems, including the immune system, the sensorimotor system, and the gut-brain axis, and that these factors simultaneously influence it. In light of this background, a new "connectivome theory" has been proposed as a hypothesis for understanding ASD. "Exercise," "nutrition," and "sleep," which are discussed in this mini-review, have a particularly strong relationship with the immune, musculoskeletal, and gut systems among the pathologies mentioned in the "connectivome theory," furthermore, many reports suggest improvements in stereo-responsive behavior and social and communication skills, which are the core symptoms of ASD. In addition, these interventions are characterized by being less subject to location and cost limitations and excel in the continuity of therapeutic intervention, and the three interventions may have a reciprocal positive impact and may function as three pillars to support ASD.

Dietary Approaches and Nutritional Complexities of Autism Spectrum Disorder

Background:

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by poor social interaction, repetitive behavior, learning difficulties, cognitive issues, and unusual eating patterns. Different factors including genetic and environmental variables have been identified to increase the risk of developing ASD.

Objective:

The main objective of the present review is to investigate the dietary approaches and modifications to reduce the intricacies related to ASD.

Results:

Studies included in this review suggested that abnormalities in the gut microbiota are involved in the pathogenesis and severity of the disease. Medical nutrition therapy for ASD consists of excluding harmful food components such as gluten, casein, processed foods, and excessive sugars and increasing the consumption of omega-3 fats, vitamins and minerals, probiotics, and antioxidants. Furthermore, awareness regarding food labels might help to avoid food allergens in diet.

Conclusion:

Active dietary treatments including the use of dietary supplements and elimination of processed foods appear to reduce the complexities of ASD. Furthermore, support of health care professionals and adopting public health approaches might help to prevent adverse outcomes related to ASD. Future research is required to determine the prevalence of ASD and related outcomes in low/middle income countries as this area is highly neglected.

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.

Efficacy and Safety of Diet Therapies in Children With Autism Spectrum Disorder: A Systematic Literature Review and Meta-Analysis

Objective

Autism Spectrum Disorder is a neurodevelopmental disorder, with a rapid increase in recognition over the past decade. Interest in alternative therapies is growing annually, such as dietary therapies including gluten-free and/or casein-free diet, and the ketogenic diet. However, there is no consensus on the efficacy and safety of dietary therapy in children with ASD up to now. This study aimed to assess the efficacy and safety of these diet interventions for children with ASD based on a meta-analysis of global data.

Methods

Seven databases (Cochrane Library, PubMed, EMBASE, Web of Science, VIP, CNKI, and Wanfang) were searched according to the established inclusion criteria, from the inception of the databases to August 18, 2021. The Cochrane Bias risk assessment tool was intended to assess the quality of the included studies. Review Manager 5.4 software was used as an efficacy analysis tool of the included studies, taking the core autistic symptoms and scales of ASD as therapeutic efficacy evaluations.

Results

In total, 7 RCTs with 338 participants were finally obtained. All studies assessed the association between core autistic symptoms and therapeutic diet, showing a statistically significant effect (standard mean difference (SMD) of −0.51, 95% confidence interval (Cl): −0.81 to −0.21), in which two studies which followed the GFD diet reported significant reductions in social behaviors (SMD of−0.41, 95% Cl: −0.75 to −0.06), showing no correlation with the length of the interventions (P < 0.05). Two studies were performed in KD diet suggested a significant effect in core symptoms (SMD of −0.67, 95% Cl: −1.04 to −0.31). No statistically significant changes were observed in the GFCF diet, GFD diet, cognition, communication, and stereotypical behaviors subgroups (all P > 0.05).

Conclusion

The results of a meta-analysis suggest that diet therapies can significantly ameliorate core symptoms of ASD, and GFD diets are conducive to improving social behaviors. Although the results suggest the effectiveness of dietary therapy for ASD, limited by the small sample size of RCTs, more well-designed, and high-quality clinical trials are needed to validate the above conclusions.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42021277565.