Dietary Considerations in Autism Spectrum Disorders: The Potential Role of Protein Digestion and Microbial Putrefaction in the Gut-Brain Axis

Associations between genetically determined dietary factors and risk of autism spectrum disorder: a Mendelian randomization study

Background

Existing studies confirm the importance of dietary factors in developing autism spectrum disorder (ASD) and disease progression. Still, these studies are primarily observational, and their causal relationship is unknown. Moreover, due to the extensive diversity of food types, the existing research remains somewhat limited in comprehensiveness. The inconsistency of the results of some studies is very disruptive to the clinic. This study infers a causal relationship between dietary factors on the risk of developing ASD from a genetic perspective, which may lead to significant low-cost benefits for children with ASD once the specificity of dietary factors interfering with ASD is confirmed.

Methods

We performed a two-sample Mendelian randomization (MR) analysis by selecting single nucleotide polymorphisms (SNPs) for 18 common dietary factors from the genome-wide association study (GWAS) database as instrumental variables (IVs) and obtaining pooled data for ASD (Sample size = 46,351) from the iPSYCH-PGC institution. Inverse variance weighted (IVW) was used as the primary analytical method to estimate causality, Cochran's Q test to assess heterogeneity, the Egger-intercept test to test for pleiotropy and sensitivity analysis to verify the reliability of causal association results.

Results

The MR analysis identified four dietary factors with potential causal relationships: poultry intake (fixed-effects IVW: OR = 0.245, 95% CI: 0.084-0.718, P < 0.05), beef intake (fixed-effects IVW: OR = 0.380, 95% CI: 0.165-0.874, P < 0.05), cheese intake (random-effects IVW: OR = 1.526, 95% CI: 1.003-2.321, P < 0.05), and dried fruit intake (fixed-effects IVW: OR = 2.167, 95% CI: 1.342-3.501, P < 0.05). There was no causal relationship between the remaining 14 dietary factors and ASD (P > 0.05).

Conclusion

This study revealed potential causal relationships between poultry intake, beef intake, cheese intake, dried fruit intake, and ASD. Poultry and beef intake were associated with a reduced risk of ASD, while cheese and dried fruit intake were associated with an increased risk. Other dietary factors included in this study were not associated with ASD.

Assessment of Technological and Sensory Properties, Digestibility, and Bioactive Compounds in Polentas from Different Maize Genotypes

The sensory profile of polenta and the connections between technological attributes and varieties of maize have not been extensively studied. Thus, it is necessary to understand the possible effect of its consumption on consumers' health in terms of postprandial glucose levels and molecules associated with healthy activities. This work aims to study polenta's technological and sensory properties from different maize genotypes and evaluate their digestibility and the potential contribution of bioactive compounds on health. A commercial hybrid, two open-pollinated varieties, and three inbred lines were used. Grain physical determinations and physical-chemical semolina traits were determined. Polenta's technological quality was evaluated after simulated cooking. In vitro digestion was performed for polentas, and a sensory evaluation test was conducted. A significant correlation was found between semolina polyphenols and rapidly digestible starch (r = -0.6). Panellists characterised the genotype C6006 as having a good flavour, sandier mouthfeel, and low consistency. Also, the polenta from the hybrid exhibited sensory attributes more closely resembling commercial polenta in terms of maize odour, flavour, and consistency. The higher content of polyphenols presents in semolina affected the digestion of polenta, showing a lower proportion of rapidly digestible starch and a lower amount of bioaccessible protein fraction.

Advances in the Treatment of Autism Spectrum Disorder: Current and Promising Strategies

Autism spectrum disorder (ASD) is an umbrella term for developmental disorders characterized by social and communication impairments, language difficulties, restricted interests, and repetitive behaviors. Current management approaches for ASD aim to resolve its clinical manifestations based on the type and severity of the disability. Although some medications like risperidone show potential in regulating ASD-associated symptoms, a comprehensive treatment strategy for ASD is yet to be discovered. To date, identifying appropriate therapeutic targets and treatment strategies remains challenging due to the complex pathogenesis associated with ASD. Therefore, a comprehensive approach must be tailored to target the numerous pathogenetic pathways of ASD. From currently viable and basic treatment strategies, this review explores the entire field of advancements in ASD management up to cutting-edge modern scientific research. A novel systematic and personalized treatment approach is suggested, combining the available medications and targeting each symptom accordingly. Herein, summarize and categorize the most appropriate ways of modern ASD management into three distinct categories: current, promising, and prospective strategies.

Microbiota in Autism Spectrum Disorder: A Systematic Review

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition characterized by several core symptoms: restricted interests, communication difficulties, and impaired social interactions. Many ASD children experience gastrointestinal functional disorders, impacting their well-being. Emerging evidence suggests that a gut microbiota imbalance may exacerbate core and gastrointestinal symptoms. Our review assesses the gut microbiota in children with ASD and interventions targeting microbiota modulation. The analysis of forty-four studies (meta-analyses, reviews, original research) reveals insights into the gut microbiota-ASD relationship. While specific microbiota alterations are mixed, some trends emerge. ASD children exhibit increased Firmicutes (36-81%) and Pseudomonadota (78%) and decreased Bacteroidetes (56%). The Bacteroidetes to Firmicutes ratio tends to be lower (56%) compared to children without ASD, which correlates with behavioral and gastrointestinal abnormalities. Probiotics, particularly Lactobacillus, Bifidobacterium, and Streptococcus strains, show promise in alleviating behavioral and gastrointestinal symptoms (66%). Microbiota transfer therapy (MTT) seems to have lasting benefits for the microbiota and symptoms in one longitudinal study. Prebiotics can potentially help with gastrointestinal and behavioral issues, needing further research for conclusive efficacy due to different interventions being used. This review highlights the gut microbiota-ASD interplay, offering potential therapeutic avenues for the gut-brain axis. However, study heterogeneity, small sample sizes, and methodological variations emphasize the need for comprehensive, standardized research. Future investigations may unveil complex mechanisms linking the gut microbiota to ASD, ultimately enhancing the quality of life for affected individuals.

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.

Dietary pattern in autism increases the need for probiotic supplementation: A comprehensive narrative and systematic review on oxidative stress hypothesis

Autism spectrum disorders (ASDs) are associated with specific dietary habits, including limited food selection and gastrointestinal problems, resulting in an altered gut microbiota. Autistic patients have an elevated abundance of certain gut bacteria associated with increased oxidative stress in the gastrointestinal tract. Probiotic supplementation has been shown to decrease oxidative stress in a simulated gut model, but the antioxidant effects of probiotics on the oxidative stress of the gut in autistic patients have not been directly studied. However, it is speculated that probiotic supplementation may help decrease oxidative stress in the gastrointestinal tract of autistic patients due to their specific dietary habits altering the microbiota. PubMed, Scopus and Web of Science databases and Google Scholar were searched up to May 2023. This systematic-narrative review aims to present the latest evidence regarding the changes in eating habits of autistic children which may further increase the gut microbiota induced oxidative stress. Additionally, this review will assess the available literature on the effects of probiotic supplementation on oxidative stress parameters.

Integrative analysis of γδT cells and dietary factors reveals predictive values for autism spectrum disorder in children

BACKGROUND

Autism spectrum disorder (ASD) includes a range of multifactorial neurodevelopmental disabilities characterized by a variable set of neuropsychiatric symptoms. Immunological abnormalities have been considered to play important roles in the pathogenesis of ASD, but it is still unknown which abnormalities are more prominent.

METHODS

A total of 105 children with ASD and 105 age and gender-matched typically developing (TD) children were recruited. An eating and mealtime behavior questionnaire, dietary habits, and the Bristol Stool Scale were investigated. The immune cell profiles in peripheral blood were analyzed by flow cytometry, and cytokines (IFN-γ, IL-8, IL-10, IL-17A, and TNF-α) in plasma were examined by Luminex assay. The obtained results were further validated using an external validation cohort including 82 children with ASD and 51 TD children.

RESULTS

Compared to TD children, children with ASD had significant eating and mealtime behavioral changes and gastrointestinal symptoms characterized by increased food fussiness and emotional eating, decreased fruit and vegetable consumption, and increased stool astriction. The proportion of γδT cells was significantly higher in children with ASD than TD children (β: 0.156; 95% CI: 0.888 ∼ 2.135, p < 0.001) even after adjusting for gender, eating and mealtime behaviors, and dietary habits. In addition, the increased γδT cells were evident in all age groups (age < 48 months: β: 0.288; 95% CI: 0.420 ∼ 4.899, p = 0.020; age ≥ 48 months: β: 0.458; 95% CI: 0.694 ∼ 9.352, p = 0.024), as well as in boys (β: 0.174; 95% CI: 0.834 ∼ 2.625, p < 0.001) but not in girls. These findings were also confirmed by an external validation cohort. Furthermore, IL-17, but not IFN-γ, secretion by the circulating γδT cells was increased in ASD children. Machine learning revealed that the area under the curve in nomogram plots for increased γδT cells combined with eating behavior/dietary factors was 0.905, which held true in both boys and girls and in all the age groups of ASD children. The decision curves showed that children can receive significantly higher diagnostic benefit within the threshold probability range from 0 to 1.0 in the nomogram model.

CONCLUSIONS

Children with ASD present with divergent eating and mealtime behaviors and dietary habits as well as gastrointestinal symptoms. In peripheral blood, γδT cells but not αβT cells are associated with ASD. The increased γδT cells combined with eating and mealtime behavior/dietary factors have a high value for assisting in the diagnosis of ASD.

An Overview on Fecal Profiles of Amino Acids and Related Amino-Derived Compounds in Children with Autism Spectrum Disorder in Tunisia

Autism spectrum disorder (ASD) is a neurodevelopmental pathology characterized by the impairment of social interaction, difficulties in communication, and repetitive behaviors. Alterations in the metabolism of amino acids have been reported. We performed a chromatographic analysis of fecal amino acids, ammonium, biogenic amines, and gamma aminobutyric acid (GABA) in Tunisian autistic children from 4 to 10 years, and results were compared with their siblings (SIB) and children from the general population (GP). ASD presented significantly higher levels of fecal amino acids than SIB and GP; differences being more pronounced in younger (4–7 years) than in older (8–10 years) individuals whereas no changes were found for the remaining compounds. Lower levels of histidine were the only difference related with severe symptoms of autism (CARS scale). A linear discriminant analysis (LDA) based on fecal amino acid profiles clearly separated ASD, SIB, and GP at 4 to 7 years but not at more advanced age (8–10 years), evidencing more pronounced alterations in younger children. The relationship of fecal amino acids with autism needs deeper research integrating blood analytical parameters, brain metabolism, and intestinal microbiota. Fecal amino acids could be targeted for designing personalized diets to prevent or minimize cognitive impairments associated with ASD.

Epigenetics and the role of nutraceuticals in health and disease

In the post-genomic era, the data provided by complete genome sequencing could not answer several fundamental questions about the causes of many noninfectious diseases, diagnostic biomarkers, and novel therapeutic approaches. The rapidly expanding understanding of epigenetic mechanisms, as well as widespread acceptance of their hypothesized role in disease induction, facilitated the development of a number of novel diagnostic markers and therapeutic concepts. Epigenetic aberrations are reversible in nature, which enables the treatment of serious incurable diseases. Therefore, the interest in epigenetic modulatory effects has increased over the last decade, so about 60,000 publications discussing the expression of epigenetics could be detected in the PubMed database. Out of these, 58,442 were published alone in the last 10 years, including 17,672 reviews (69 historical articles), 314 clinical trials, 202 case reports, 197 meta-analyses, 156 letters to the editor, 108 randomized controlled trials, 87 observation studies, 40 book chapters, 22 published lectures, and 2 clinical trial protocols. The remaining publications are either miscellaneous or a mixture of the previously mentioned items. According to the species and gender, the publications included 44,589 human studies (17,106 females, 14,509 males, and the gender is not mentioned in the remaining papers) and 30,253 animal studies. In the present work, the role of epigenetic modulations in health and disease and the influencing factors in epigenetics are discussed.

Purine signaling pathway dysfunction in autism spectrum disorders: Evidence from multiple omics data

Introduction

Previous studies have suggested that the dysregulation of purine metabolism may be associated with autism spectrum disorder (ASD). Here, we adopted metabolomics and transcriptomics to verify and explore the underlying molecular mechanism of purine metabolism dysfunction in ASD and identify potential biomarkers within the purine metabolism pathway.

Methods

Ultra-high-performance liquid chromatography-mass spectrometry was used to obtain the plasma metabolic profiles of 12 patients with ASD and 12 typically developing (TD) children. RNA sequencing was used to screen differentially expressed genes related to the purine metabolic pathway and purine receptor-coding genes in 24 children with ASD and 21 healthy controls. Finally, serum uric acid levels were compared in 80 patients with ASD and 174 TD children to validate the omics results.

Results

A total of 66 identified metabolites showed significant between-group differences. Network analysis showed that purine metabolism was the most strongly enriched. Uric acid was one of the most highlighted nodes within the network. The transcriptomic study revealed significant differential expression of three purine metabolism-related genes (adenosine deaminase, adenylosuccinate lyase, and bifunctional enzyme neoformans 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) transformylase/inosine monophosphate (IMP) cyclohydrolase) (p < 0.01) and five purinergic receptor genes (P2X7, P2Y2, P2Y6, P2Y8, and P2Y10) (p < 0.05). In the validation sample, there was a significant difference in serum uric acid levels between the two groups (p < 0.001), and the area under the curve for uric acid was 0.812 (sensitivity, 82.5%; specificity, 63.8%).

Discussion

Patients with ASD had dysfunctional purine metabolic pathways, and blood uric acid may be a potential biomarker for ASD.

Nutrient intake and adequacy in children with autism spectrum disorder: EPINED epidemiological study

LAY ABSTRACT

Children with autism spectrum disorder (ASD) have a fivefold elevated risk of developing eating problems, which predisposes them to nutritional deficiencies. This study assesses nutritional intake and adequacy in children with ASD, subdiagnostic autistic symptoms and typically developing (TD) children. Preschool children with ASD and subdiagnostic symptoms had slightly lower intake of monounsaturated fatty acids (MUFA), vitamin D and vitamin B12. Primary school children with ASD and subdiagnostic symptoms had slightly higher intake of protein, cholesterol, thiamine and niacin, and a higher percentage of obesity than children with TD. All children had a high intake in sugars, fats and saturated fatty acids; a very highly inadequate intake of vitamins (vitamins D and E), fibre, b-carotene, calcium and magnesium; and a moderately inadequate intake of vitamin C, folate and iron. However, although all children need nutrition advice, children with ASD and subdiagnostic autistic symptoms had a poorer quality diet than those with TD.

Altered gut microbiota correlates with behavioral problems but not gastrointestinal symptoms in individuals with autism

BACKGROUND

Despite inconsistent results across studies, emerging evidence suggests that the microbial micro-environment may be associated with autism spectrum disorder (ASD). Geographical and cultural factors highly impact microbial profiles, and there is a shortage of data from East Asian populations. This study aimed to comprehensively characterize microbial profiles in an East Asian sample and explore whether gut microbiota contributes to clinical symptoms, emotional/behavioral problems, and GI symptoms in ASD.

METHODS

We assessed 82 boys and young men with ASD and 31 typically developing controls (TDC), aged 6-25 years. We analyzed the stool sample of all participants with 16S V3-V4 rRNA sequencing and correlated its profile with GI symptoms, autistic symptoms, and emotional/behavioral problems.

RESULTS

Autistic individuals, compared to TDC, had worse GI symptoms. There were no group differences in alpha diversity of species richness estimates (Shannon-wiener and Simpson diversity indices). Participants with ASD had an increased relative abundance of Fusobacterium, Ruminococcus torques group (at the genus level), and Bacteroides plebeius DSM 17135 (at the species level), while a decreased relative abundance of Ruminococcaceae UCG 013, Ervsipelotrichaceae UCG 003, Parasutterella, Clostridium sensu stricto 1, Turicibacter (at the genus level), and Clostridium spiroforme DSM 1552 and Intestinimonas butyriciproducens (at the species level). Altered taxonomic diversity in ASD significantly correlated with autistic symptoms, thought problems, delinquent behaviors, self dysregulation, and somatic complaints. We did not find an association between gut symptoms and gut microbial dysbiosis.

CONCLUSIONS

Our findings suggest that altered microbiota are associated with behavioral phenotypes but not GI symptoms in ASD. The function of the identified microbial profiles mainly involves the immune pathway, supporting the hypothesis of a complex relationship between altered microbiome, immune dysregulation, and ASD that may advance the discovery of molecular biomarkers for ASD.

Potential natural products for the management of autism spectrum disorder

Autism in a broader sense is a neurodevelopmental disorder, which frequently occurs during early childhood and can last for a lifetime. This condition is primarily defined by difficulties with social engagement, with individuals displaying repetitive and stereotyped behaviors. Numerous neuroanatomical investigations on autistic children have revealed that their brains grow atypically, resulting in atypical neurogenesis, neuronal migration, maturation, differentiation, and degeneration. Special education programs, speech therapy, and occupational therapy have all been used to address autism-related behavioral problems. While widely prescribed antidepressant drugs, antipsychotics, anticonvulsants, and stimulants have demonstrated response in autistic individuals. However, these medications do not fully reverse the core symptoms associated with autism spectrum disorder (ASD). The adverse reactions of ASD medicines and an increased risk of developing various other problems, such as obesity, dyslipidemia, diabetes mellitus, and thyroid disorders, prompted the researchers to investigate herbal medicines for the treatment of autistic individuals. Clinical trials are now being done to establish the efficacy of alternative techniques based on natural substances and to understand better the context in which they may be used to treat autism. This review of literature will look at crucial natural compounds derived from animals and plants that have shown promise as safe and effective autism treatment strategies.

[Functional feeding to alleviate gastrointestinal disorders associated with autism spectrum disorders: A systematic review]

BACKGROUND

gastrointestinal disorders (GIDs) are common comorbidities in patients with autism spectrum disorders (ASD); treatments with gluten- and casein-free (LGLC) diets or prebiotic/probiotic supplements may reduce the severity of GIDs.

OBJECTIVE

to integrate and discuss the evidence on the effectiveness of LGLC diet therapies and prebiotic/probiotic supplements on GIDs in patients with ASD.

METHODOLOGY

the guidelines for the publication of systematic reviews and meta-analyses (PRISMA) were used. Participant characteristics, dietary interventions, prebiotic/prebiotic supplementation, effects of interventions on GIDs, risk of bias, and safety of treatments were analyzed.

RESULTS

fifteen investigations were analyzed; the prevalence of GIDs among patients with ASD was high (58 %; range, 27-83 %). In more than 20 % of the patients managed with LGLC diets or supplements GID severity decreased (mainly constipation, diarrhea, and abdominal pain). Increases in the counts of beneficial bacteria and a decrease in the proportion of pathogenic bacteria were reported after supplement use. However, all these investigations had significant methodological biases.

CONCLUSIONS

although reductions in the frequency and severity of some GIDs have been found, the effectiveness of these treatments has not been proven yet. Given the methodological differences in the investigations, the design of rigorous studies to evaluate the therapeutic effects of these treatments on gastrointestinal health in patients with ASD is warranted.

The Gut Microbiome in Depression and Potential Benefit of Prebiotics, Probiotics and Synbiotics: A Systematic Review of Clinical Trials and Observational Studies

An emerging body of literature demonstrates differences in the gut microbiome (GMB) of patients with major depressive disorder (MDD) compared to healthy controls (HC), as well as the potential benefits of prebiotic, probiotic, and synbiotic treatment. We conducted a systematic review of 24 observational studies (n = 2817), and 19 interventional trials (n = 1119). We assessed alpha diversity, beta diversity, and taxa abundance changes in patients with MDD relative to HC, as well as the effect of prebiotics, probiotics, and synbiotics on depressive symptoms in individuals with clinical or subclinical depression. We observed no significant differences in alpha diversity but a significant difference in beta diversity between patients with MDD and HC. There were fluctuations in the abundance of specific taxa in patients with MDD relative to HC. Probiotic and synbiotic, but not prebiotic, treatment showed a modest benefit in reducing depressive symptoms in patients with MDD over four to nine weeks. The GMB profiles of patients with MDD differ significantly from HC, but further studies are needed to elucidate the benefits of prebiotic, probiotic and synbiotic treatments relative to antidepressants and over longer follow-up before these therapies are implemented into clinical practice.

Docosahexaenoic and Eicosapentaenoic Intervention Modifies Plasma and Erythrocyte Omega-3 Fatty Acid Profiles But Not the Clinical Course of Children With Autism Spectrum Disorder: A Randomized Control Trial

Background

The pathogenesis of autism spectrum disorder (ASD) is under investigation and one of the main alterations relates to the metabolic and inflammatory system dysfunctions. Indeed, based on a possible deficit of omega-3 fatty acids (FAs) of patients with ASD and looking for an anti-inflammatory effect, dietary supplements with omega-3 fatty acids have been proposed. We aimed to evaluate differences in plasma and erythrocyte FA profiles and plasma cytokines in patients with infantile ASD after supplementation with docosahexaenoic (DHA) and eicosapentaenoic (EPA) acids or placebo and both compared at baseline with a reference healthy group.

Methods

A double-blind, randomized placebo-controlled intervention with DHA/EPA for 6 months was carried out in 54 children between 2 and 6 years diagnosed with ASD. They were selected and randomly assigned into two groups: 19 children received 800 mg/day of DHA and 25 mg/day of EPA, or placebo. In addition, another reference group of 59 healthy children of the same age was included. Plasma lipids and cytokines, and FA profiles in plasma and erythrocytes were measured at baseline and after 6 months of treatment in ASD children, and at baseline in the reference group.

Results

There were no differences in demographic, anthropometric characteristics, and omega-3 intake between the healthy reference group and the ASD children at baseline. Children with ASD showed the higher plasma percentages of palmitic acid and total saturated FA and lower total omega-6 polyunsaturated FA (PUFA) compared with healthy children. An increased level of DHA and reduced EPA level in erythrocytes were detected in the ASD group vs. the reference group. After 6 months of treatment, the ASD group that received DHA enriched product significantly increased the plasma and erythrocyte percentages of DHA, but no differences were observed in the clinical test scores and other parameters as plasma cytokines between the two groups of ASD related to the intervention.

Conclusion

Spanish children with ASD exhibit an appropriate omega-3 FA status in plasma and erythrocytes. Neither a clinical improvement of ASD children nor a better anti-inflammatory or fatty acid state has been found after an intervention with DHA/EPA for 6 months. So, the prescription of n-3 LC-PUFA and other dietary supplements in ASD should be only indicated after a confirmed alteration of FA metabolism or omega-3 LC-PUFA deficiency evaluated by specific erythrocyte FA.

Clinical Trial Registration

[www.ClinicalTrials.gov], identifier [NCT03620097].

An anxious relationship between Autism Spectrum Disorder and Gut Microbiota: A tangled chemistry?

Autism spectrum disorder (ASD) is a serious multifactorial neurodevelopmental disorder often accompanied by strained social communication, repetitive behaviour, immune dysregulation, and gastrointestinal (GI) issues. Recent studies have recorded a link between dysbiosis in the gut microbiota (gm) and the primary stages of ASD. A bidirectional connection (also called microbiota-gut-brain-axis) exchanges information between the gut bacteria and central nervous system. When the homeostasis of the microenvironment of the gut is dysregulated, it causes oxidative stress, affecting neuronal cells and neurotransmitters, thereby causing neurodevelopmental disorders. Studies have confirmed a difference in the constitution of gut bacteria among ASD cases and their controls. Numerous studies on animal models of ASD have shown altered gm and its association with abnormal metabolite profile and altered behaviour phenotype. This process happens due to an abnormal metabolite production in gm, leading to changes in the immune system, especially in ASD. Hence, this review aims to question the current knowledge on gm dysbiosis and its related GI discomforts and ASD behavioural symptoms and shed light on the possible therapeutic approaches available to deal with this situation. Thereby, though it is understood that more research might be needed to prove an association or causal relationship between gm and ASD, therapy with the microbiome may also be considered as an effective strategy to combat this issue.

Intergeneration transfer of diet patterns? Parental self-report of diet and their report of their young adult children with ASD

Autism Spectrum Disorder (ASD) affects two percent of American children and often results in neophobia, hypersensitivity to foods, and firmly set food preferences, leading to higher proportions of individuals suffering from diet-related chronic diseases. Our objective was to conduct an explorative pilot study to examine parents’ perception of food intake for themselves and their young adult children with ASD. We employed comparative analysis to discover potential pathways to improve diet quality and lower the risk for chronic disease in individuals with ASD. Data from an online survey in n = 493 parent-child dyads on parentally reported intake patterns, food group, and food consumption was analyzed using kappa statistics to determine the level of agreement between reported parental and child intake patterns, body weight status and activity level. Average age was 48 years for parents and 22 years for their children, respectively. Parent-child agreement for obesity was high. We found very strong agreement between the reported diet variety (kappa = 0.82) and changing daily intake (kappa = 0.63) and strong agreement for some vegetable intake patterns (kappa = 0.61 for orange, white, and starchy vegetables) but not in meat intake (no agreement). Results of this study indicate evidence for perceived intergenerational transfer of dietary intake patterns, which may offer effective approaches to change parental diet, to subsequently improve diet quality in young adults with ASD and prevent diet-related chronic diseases in individuals with ASD.

Paving Plant-Food-Derived Bioactives as Effective Therapeutic Agents in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a neurodevelopmental disorder, where social and communication deficits and repetitive behaviors are present. Plant-derived bioactives have shown promising results in the treatment of autism. In this sense, this review is aimed at providing a careful view on the use of plant-derived bioactive molecules for the treatment of autism. Among the plethora of bioactives, curcumin, luteolin, and resveratrol have revealed excellent neuroprotective effects and can be effectively used in the treatment of neuropsychological disorders. However, the number of clinical trials is limited, and none of them have been approved for the treatment of autism or autism-related disorder. Further clinical studies are needed to effectively assess the real potential of such bioactive molecules.

Perspective on prenatal polychlorinated biphenyl exposure and the development of the progeny nervous system (Review)

The developmental origins of health and disease concept illustrates that exposure in early life to various factors may affect the offspring's long-term susceptibility to disease. During development, the nervous system is sensitive and vulnerable to the environmental insults. Polychlorinated biphenyls (PCBs), which are divided into dioxin-like (DL-PCBs) and non-dioxin-like PCBs (NDL-PCBs), are synthetic persistent environmental endocrine-disrupting chemicals. The toxicological mechanisms of DL-PCBs have been associated with the activation of the aryl hydrocarbon receptor and NDL-PCBs have been associated with ryanodine receptor-mediated calcium ion channels, which affect neuronal migration, promote dendritic growth and alter neuronal connectivity. In addition, PCB accumulation in the placenta destroys the fetal placental unit and affects endocrine function, particularly thyroid hormones and the dopaminergic system, leading to neuroendocrine disorders. However, epidemiological investigations have not achieved a consistent result in different study cohorts. The present review summarizes the epidemiological differences and possible mechanisms of the effects of intrauterine PCB exposure on neurological development.

Fecal Microbiome Transplantation from Children with Autism Spectrum Disorder Modulates Tryptophan and Serotonergic Synapse Metabolism and Induces Altered Behaviors in Germ-Free Mice

To determine the relationship of the gut microbiota and its metabolites with autism spectrum disorder (ASD)-like behaviors and preliminarily explore the potential molecular mechanisms, the fecal microbiota from donors with ASD and typically developing (TD) donors were transferred into germ-free (GF) mice to obtain ASD-FMT mice and TD-FMT mice, respectively. Behavioral tests were conducted on these mice after 3 weeks. 16S rRNA gene sequencing of the cecal contents and untargeted metabolomic analysis of the cecum, serum, and prefrontal cortex were performed. Untargeted metabolomics was also used to analyze fecal samples of TD and ASD children. Western blotting detected the protein expression levels of tryptophan hydroxylase 1 (TPH1), serotonin transporter (SERT), and serotonin 1A receptor (5-HT1AR) in the colon and TPH2, SERT, and 5-HT1AR in the prefrontal cortex of mice. ASD-FMT mice showed ASD-like behavior and a microbial community structure different from that of TD-FMT mice. Tryptophan and serotonin metabolisms were altered in both ASD and TD children and ASD-FMT and TD-FMT mice. Some microbiota may be related to tryptophan and serotonin metabolism. Compared with TD-FMT mice, ASD-FMT mice showed low SERT and 5-HT1AR and high TPH1 expression levels in the colon. In the prefrontal cortex, the expression levels of TPH2 and SERT were increased in the ASD-FMT group relative to the TD-FMT group. Therefore, the fecal microbiome of ASD children can lead to ASD-like behaviors, different microbial community structures, and altered tryptophan and serotonin metabolism in GF mice. These changes may be related to changes in some key proteins involved in the synthesis and transport of serotonin.

IMPORTANCE The relationship between the gut microbiota and ASD is not yet fully understood. Numerous studies have focused on the differences in intestinal microbial and metabolism profiles between TD and ASD children. However, it is still not clear if these microbes and metabolites cause the development of ASD symptoms. Here, we collected fecal samples from TD and ASD children, transplanted them into GF mice, and found that the fecal microbiome of ASD children can lead to ASD-like behaviors, different microbial community structures, and altered tryptophan and serotonin metabolism in GF mice. We also demonstrated that tryptophan and serotonin metabolism was also altered in ASD and TD children. Together, these findings confirm that the microbiome from children with ASD may lead to ASD-like behavior of GF mice through metabolites, especially tryptophan and serotonin metabolism.

High animal protein diet and gut microbiota in human health

The role of the intestinal flora in health and disease has become a research hotspot. Compared with carbohydrates and fats, proteins are metabolized primarily by microbial fermentation in the intestine. The production of protein fermentation products and metabolites depends on the composition, diversity, and metabolism of the gut microbiota. Several protein fermentation products, including indoles, phenols, polyamines, hydrogen sulfide (H₂S), amines, and carnitine, are toxic. This study analyzes the relationship between high-protein diets (HPDs), the intestinal microbiota, and human health and disease. Long-term HPDs increase the risk of intestinal diseases, type 2 diabetes (T2DM), obesity, central nervous system (CNS) diseases, and cardiovascular diseases (CVD) by producing toxic metabolites in the colon, including amines, H₂S, and ammonia. Short-term HPDs have little effect on the metabolism of healthy individuals under 65 years old. However, meeting the protein requirements of individuals over 65 years old using HPDs is more challenging. The adverse effects of HPDs on athletes are minimal. Natural compounds (plant extracts, whose main constituents are polysaccharides and polyphenols), prebiotics, probiotics, and regular physical exercise improve gut dysbiosis and reduce disease risk.

The interplay between gut microbiota and autism spectrum disorders: A focus on immunological pathways

Autism spectrum disorders (ASD) are a group of neurodevelopmental disorders characterized by impairments in social and cognitive activities, stereotypical and repetitive behaviors and restricted areas of interest. A remarkable proportion of ASD patients represent immune dysregulation as well as gastrointestinal complications. Hence, a novel concept has recently emerged, addressing the possible intercommunication between the brain, the immune system, the gut and its commensals. Here, we provide an overview of how gut microbes and their metabolites are associated with neurobehavioral features of ASD through various immunologic mechanisms. Moreover, we discuss the potential therapeutic options that could modify these features.

Plasma and Fecal Metabolite Profiles in Autism Spectrum Disorder

BACKGROUND

Autism spectrum disorder (ASD) is a neurodevelopmental condition with hallmark behavioral manifestations including impaired social communication and restricted repetitive behavior. In addition, many affected individuals display metabolic imbalances, immune dysregulation, gastrointestinal dysfunction, and altered gut microbiome compositions.

METHODS

We sought to better understand nonbehavioral features of ASD by determining molecular signatures in peripheral tissues through mass spectrometry methods (ultrahigh performance liquid chromatography-tandem mass spectrometry) with broad panels of identified metabolites. Herein, we compared the global metabolome of 231 plasma and 97 fecal samples from a large cohort of children with ASD and typically developing control children.

RESULTS

Differences in amino acid, lipid, and xenobiotic metabolism distinguished ASD and typically developing samples. Our results implicated oxidative stress and mitochondrial dysfunction, hormone level elevations, lipid profile changes, and altered levels of phenolic microbial metabolites. We also revealed correlations between specific metabolite profiles and clinical behavior scores. Furthermore, a summary of metabolites modestly associated with gastrointestinal dysfunction in ASD is provided, and a pilot study of metabolites that can be transferred via fecal microbial transplant into mice is identified.

CONCLUSIONS

These findings support a connection between metabolism, gastrointestinal physiology, and complex behavioral traits and may advance discovery and development of molecular biomarkers for ASD.

2D:4D Ratio and Autism Spectrum Disorder in Brunei Darussalam

Background

Despite the global increase in the prevalence of autism spectrum disorders (ASD), relevant research studies are lacking in Brunei Darussalam. Various studies have shown a significant association between a lowered 2D:4D ratio (ratio of second digit/index finger to the fourth digit/ring finger) and ASD, making it one of the potential phenotypic biomarkers for early detection of autism, which is important for early intervention and management.

Objective

The objective of this study is to explore the association between 2D:4D ratio and ASD in Brunei Darussalam, as a potential tool to complement early ASD diagnosis.

Methods

We conducted a case–control study comprising 28 ASD and 62 typically developing (TD) children in the case and control group, respectively (age range: 3–11 years old; median age: 6 years old). Median 2D:4D ratios were measured, compared and analysed between the two groups. Logistic regression models were used to explore potential associations between the median 2D:4D ratio and ASD in respective gender, for both left and right hands, independently.

Results

Our study shows that the median 2D:4D ratio of left hand in ASD males is significantly lower than those in TD males, after adjusting for ethnicity and age [Odds Ratio (OR) = 0.57 (95% Confidence Interval (CI): 0.31–0.96); p = 0.044]. For females, there is no association of ASD with the median left hand 2D:4D ratio [OR = 3.09 (95% CI: 0.98–19.86); p = 0.144] or the median right hand 2D:4D ratio [OR = 1.23 (95% CI: 0.42–3.88); p = 0.702]. Our study also shows a significant positive correlation and/or a reduced asymmetry between the average 2D:4D ratio of left hands and right hands in ASD males (Pearson’s correlation (r) = 0.48; 95% CI: 0.076–0.75, p = 0.023).

Conclusions

There is significant association between a lowered median 2D:4D ratio of the left hand (in males only) and ASD diagnosis. Once validated in a larger sample size, a lowered median 2D:4D ratio on the left hand may be a potential tool to complement ASD diagnosis for males in our study population. There is no association between the median 2D:4D ratio (left or right hands) and ASD in females, which could be due to the small female sample size and/or the possibility of different aetiology for ASD in females. Reduced asymmetry between the average 2D:4D ratio of left and right hands observed in ASD males only (not in ASD females) also suggests the importance of considering gender-specific biomarkers for ASD diagnosis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10803-021-04899-9.

Gut microbiota metabolites in autistic children: An epigenetic perspective

Gut microbiota has become an issue of great importance recently due to its major role in autism spectrum disorder (ASD). Over the past three decades, there has been a sustained research activity focused to explain the actual mechanism by which gut microbiota triggers/develops autism. Several genetic and epigenetic factors are involved in this disorder, with epigenetics being the most active area of research. Although the constant investigation and advancements, epigenetic implications in ASD still need a deeper functional/causal analysis. In this review, we describe the major gut microbiota metabolites and how they induce epigenetic changes in ASD along with interactions through the gut-brain axis.

The Gut-Brain-Immune Axis in Autism Spectrum Disorders: A State-of-Art Report

The interest elicited by the large microbial population colonizing the human gut has ancient origins and has gone through a long evolution during history. However, it is only in the last decades that the introduction of high-throughput technologies has allowed to broaden this research field and to disentangle the numerous implications that gut microbiota has in health and disease. This comprehensive ecosystem, constituted mainly by bacteria but also by fungi, parasites, and viruses, is proven to be involved in several physiological and pathological processes that transcend the intestinal homeostasis and are deeply intertwined with apparently unrelated body systems, such as the immune and the nervous ones. In this regard, a novel speculation is the relationship between the intestinal microbial flora and the pathogenesis of some neurological and neurodevelopmental disorders, including the clinical entities defined under the umbrella term of autism spectrum disorders. The bidirectional interplay has led researchers to coin the term gut-brain-immune system axis, subverting the theory of the brain as an immune-privileged site and underscoring the importance of this reciprocal influence already from fetal life and especially during the pre- and post-natal neurodevelopmental process. This revolutionary theory has also unveiled the possibility to modify the gut microbiota as a way to treat and even to prevent different kinds of pathologies. In this sense, some attempts have been made, ranging from probiotic administration to fecal microbiota transplantation, with promising results that need further elaboration. This state-of-art report will describe the main aspects regarding the human gut microbiome and its specific role in the pathogenesis of autism and its related disorders, with a final discussion on the therapeutic and preventive strategies aiming at creating a healthy intestinal microbial environment, as well as their safety and ethical implications.

Gut Biofactory-Neurocompetent Metabolites within the Gastrointestinal Tract. A Scoping Review

The gut microbiota have gained much scientific attention recently. Apart from unravelling the taxonomic data, we should understand how the altered microbiota structure corresponds to functions of this complex ecosystem. The metabolites of intestinal microorganisms, especially bacteria, exert pleiotropic effects on the human organism and contribute to the host systemic balance. These molecules play key roles in regulating immune and metabolic processes. A subset of them affect the gut brain axis signaling and balance the mental wellbeing. Neurotransmitters, short chain fatty acids, tryptophan catabolites, bile acids and phosphatidylcholine, choline, serotonin, and L-carnitine metabolites possess high neuroactive potential. A scoping literature search in PubMed/Embase was conducted up until 20 June 2020, using three major search terms "microbiota metabolites" AND "gut brain axis" AND "mental health". This review aimed to enhance our knowledge regarding the gut microbiota functional capacity, and support current and future attempts to create new compounds for future clinical interventions.

Engineered probiotic and prebiotic nutraceutical supplementations in combating non-communicable disorders: A review

Nutritional supplementations are a form of nutrition sources that may help in improving health complexities throughout the life span of a person. Under the umbrella of food supplementations, nutraceuticals are products extracted from edible sources that provide medical benefits along with primary nutritional value, these can be considered as functional foods. These nutraceutical supplementations are also evidenced in altering the commensal gut microbiota and help to prevent or fight against chronic non-communicable degenerative diseases in adults including neurological disorders (Autism Spectrum Disorder [ASD], Parkinson's disease [PD] and Multiple sclerosis [MS]) and metabolic disorder (Type-II Diabetes, Obesity and non-alcoholic fatty liver disease). Even the complexities of preterm babies like extra-uterine growth restriction, necrotizing enterocolitis, infant eczema and allergy (during pregnancy) and bronchopulmonary dysplasia, etc. could also be lessened up by providing proper nutrition. Molecular perceptive of inflammatory and apoptotic modulators regulating the pathogenesis of these health risks, their control and management by probiotics and prebiotics could further emphasize the scientific overview of their utility. The pivotal role of nutraceutical supplementations in regulating or modulating molecular pathways coupled with the above mentioned non-communicable diseases are briefly described. Lastly, an overall introduction to the sophisticated genome-editing techniques and advanced delivery systems in therapeutic activities applicable under these health risks are also emphasized in this paper.

Microbiota, Immune System and Autism Spectrum Disorders: An Integrative Model towards Novel Treatment Options

BACKGROUND

Autism Spectrum Disorder (ASD) is a condition strongly associated with genetic predisposition and familial aggregation. Among ASD patients, different levels of symptoms severity are detectable, while the presence of intermediate autism phenotypes in close relatives of ASD probands is also known in literature. Recently, increasing attention has been paid to environmental factors that might play a role in modulating the relationship between genomic risk and development and severity of ASD. Within this framework, an increasing body of evidence has stressed a possible role of both gut microbiota and inflammation in the pathophysiology of neurodevelopment. The aim of this paper is to review findings about the link between microbiota dysbiosis, inflammation and ASD.

METHODS

Articles ranging from 1990 to 2018 were identified on PUBMED and Google Scholar databases, with keyword combinations as: microbiota, immune system, inflammation, ASD, autism, broad autism phenotype, adult.

RESULTS

Recent evidence suggests that microbiota alterations, immune system and neurodevelopment may be deeply intertwined, shaping each other during early life. However, results from both animal models and human samples are still heterogeneous, while few studies focused on adult patients and ASD intermediate phenotypes.

CONCLUSION

A better understanding of these pathways, within an integrative framework between central and peripheral systems, might not only shed more light on neural basis of ASD symptoms, clarifying brain pathophysiology, but it may also allow to develop new therapeutic strategies for these disorders, still poorly responsive to available treatments.

Gastrointestinal problems are associated with increased repetitive behaviors but not social communication difficulties in young children with autism spectrum disorders

LAY ABSTRACT

Individuals with autism spectrum disorder are more likely than typically developing individuals to experience a range of gastrointestinal abnormalities, including chronic diarrhea, constipation, food sensitivities, and abdominal pain. These gastrointestinal symptoms have been associated with higher levels of irritability and aggressive behavior, but less is known about their relationship with core autism spectrum disorder symptoms. We investigated the relationship between autism spectrum disorder symptom severity and gastrointestinal symptoms while accounting for three associated behavioral symptom domains (Irritability, Aggressiveness, and Specific Fears), in a sample of 176 children (140 males and 36 females) ages 2-7 years old with autism spectrum disorder. A large majority (93.2%) of the sample had at least one reported gastrointestinal symptom, and most (88.1%) participants had more than one gastrointestinal symptom. Various types of gastrointestinal symptoms were reported; the most common symptoms reported were constipation, food limits, gas/bloating, and stomach pain. After accounting for each associated behavioral symptom domain, repetitive behaviors and stereotypies were significantly associated with gastrointestinal symptom severity. Increased severity of autism spectrum disorder symptoms was correlated with increased gastrointestinal symptom severity. Social and communication difficulties were not significantly associated with gastrointestinal symptom severity after accounting for associated behavioral symptoms. Our findings replicate a previously described association between irritability and aggression and gastrointestinal symptoms. Furthermore, we found that repetitive behaviors, but not social or communication symptoms, are associated with gastrointestinal symptom severity, even after accounting for associated behavioral symptoms. This suggests that gastrointestinal symptoms may exacerbate repetitive behaviors, or vice versa, independent from other associated behavioral symptoms.

Assessment of Changes over Time of Lipid Profile, C-Reactive Protein Level and Body Mass Index in Teenagers and Young Adults on Different Diets Belonging to Autism Spectrum Disorder

Background: Numerous scientific studies on patients with autism spectrum disorder (ASD) suggest a significant role of inflammation processes or lipid disorders in this spectrum of neurodevelopmental disorders. Unfortunately, there is a lack of assessments of changes over time regarding level of lipids and inflammatory markers in people diagnosed with ASD using different diets. The aim of this study was to evaluate changes in lipid profile, high sensitivity C-reactive protein (hs-CRP) and body mass index (BMI) in individuals diagnosed with ASD and healthy controls. Variables were assessed at two time points (2015/17 and 2017/20) for each subject. Methods: After applying the selection criteria, for the first assessment period, 96 participants were qualified (the group consisted of 59 males with ASD and 37 healthy volunteers, i.e., age-matched control group—CG). The final assessment included 93 participants (57 from ASD group and 36 from CG). Subjects were on low-fat diet (LFD), gluten–casein-free diet (GF–CF) and regular diet (RD), respectively. All members of CG were on regular diet. A fasting lipid profile and hs-CRP level were analyzed. BMI and percentiles were calculated. Eating habits were checked by analyzing data from questionnaires. Principal component analysis (PCA) was used separately for every assessment. The Mann–Whitney U test was used to compare the medians of variables in the scheme of pairwise comparisons between control and ASD groups on different diets for separate assessment, while differences over time between variables were tested by Wilcoxon signed-rank test. Results: Statistically significant differences between BMI, CRP, triglycerides (TG), total cholesterol (TC), high-density lipoprotein (HDL), non-HDL-C and TC/HDL ratio were found in ASD group in comparison to healthy volunteers (increased BMI, CRP and TC/HDL and decreased HDL-C for all types of diets, increased TG in the group of LFD and RD individual and increased non-HDL-C in the group of GF–CF and RD individuals) during the first assessment period. The second assessment over time also showed increased levels of TC, non HDL-C and TC/HDL and decreased level of HDL-C for all ASD individuals regardless of diets used, while BMI and CRP increased only for individuals on LFD and RD. No statistically significant correlations between age of participants and other variables comparing with CG were found. Conclusions: Our studies suggest that targeted, individualized nutritional pattern and periodic screening for lipid and immune disorders would be beneficial for teenagers and adults diagnosed with ASD.

The Promising Role of Probiotics in Managing the Altered Gut in Autism Spectrum Disorders

Gastrointestinal symptoms (GIS) have been reported repeatedly in people with autism spectrum disorder (ASD) and studies have reported interesting correlations between severity of behavioral and gastrointestinal symptoms. Growing evidence indicates that the gut microbiota in ASD is altered with various shifts described at different taxonomic levels, pointing to the importance of considering the gut-brain axis in treatment of these disorders. Probiotics are live beneficial bacteria that are ingested as food or customized pills. These beneficial bacteria, when added in sufficient amounts, can correct the dysbiosis. Because probiotics have shown success in treating irritable bowel syndrome (IBS), it is plausible to investigate whether they can induce alleviation of behavioral symptoms as well. Probiotics show, in some clinical studies, their potential benefits (1) in improving gastrointestinal dysfunction, (2) in correcting dysbiosis, (3) in consequently reducing the severity of ASD symptoms. This review compiles data from selected studies that investigate these benefits and the mechanisms that mediate these effects, which include the production of metabolites, hormones, and neurotransmitters and the regulation of pro-inflammatory and regulatory cytokines. Future research based on more randomized, controlled studies with a larger population size and standardized use of strains, concentration of probiotics, duration of treatments, and methods of DNA extraction is still needed in this area, which may lead to more robust results.

Specialized Diet Therapies: Exploration for Improving Behavior in Autism Spectrum Disorder (ASD)

As a major neurodevelopmental disorder, Autism Spectrum Disorder (ASD) encompasses deficits in communication and repetitive and restricted interests or behaviors in childhood and adolescence. Its etiology may come from either a genetic, epigenetic, neurological, hormonal, or an environmental cause, generating pathways that often altogether play a synergistic role in the development of ASD pathogenesis. Furthermore, the metabolic origin of ASD should be important as well. A balanced diet consisting of the essential and special nutrients, alongside the recommended caloric intake, is highly recommended to promote growth and development that withstand the physiologic and behavioral challenges experienced by ASD children. In this review paper, we evaluated many studies that show a relationship between ASD and diet to develop a better understanding of the specific effects of the overall diet and the individual nutrients required for this population. This review will add a comprehensive update of knowledge in the field and shed light on the possible nutritional deficiencies, metabolic impairments (particularly in the gut microbiome), and malnutrition in individuals with ASD, which should be recognized in order to maintain the improved socio-behavioral habit and physical health.

The Regulation of Reactive Neuroblastosis, Neuroplasticity, and Nutraceuticals for Effective Management of Autism Spectrum Disorder

Autism spectrum disorder (ASD) encompasses a cluster of neurodevelopmental and genetic disorders that has been characterized mainly by social withdrawal, repetitive behavior, restricted interests, and deficits in language processing mainly in children. ASD has been known to severely impair behavioral patterns and cognitive functions including learning and memory due to defects in neuroplasticity. The biology of the ASD appears to be highly complex and heterogeneous, and thus, finding a therapeutic target for autism remains obscure. There has been no complete prevention or disease-modifying cure for this disorder. Recently, individuals with autism have been characterized by reactive neurogenesis, obstructions in axonal growth, heterotopia, resulting from dysplasia of neuroblasts in different brain regions. Therefore, it can be assumed that the aforementioned neuropathological correlates seen in the autistic individuals might originate from the defects mainly in the regulation of neuroblasts in the developing as well as adult brain. Nutrient deficiencies during early brain development and intake of certain allergic foods have been proposed as main reasons for the development of ASD. However, the integrated understanding of neurodevelopment and functional aspects of neuroplasticity working through neurogenesis in ASD is highly limited. Moreover, neurogenesis at the level of neuroblasts can be regulated by nutrition. Hence, defects in neuroblastosis underlying the severity of autism potentially could be rectified by appropriate implementation of nutraceuticals.

Assessments of Amino Acids, Ammonia and Oxidative Stress Among Cohort of Egyptian Autistic Children: Correlations with Electroencephalogram and Disease Severity

OBJECTIVE

The current study aimed to assess the profiles of plasma amino acids, serum ammonia and oxidative stress status among autistic children in terms of electroencephalogram findings and clinical severity among the cohort of autistic Egyptian children.

PATIENTS AND METHODS

The present study included 118 Egyptian children categorized into 54 children with autism who were comparable with 64 healthy controls. Clinical assessments of cases were performed using CARS in addition to EEG records. Plasma amino acids were measured using high-performance liquid chromatography (HPLC), while, serum ammonia and oxidative stress markers were measured using colorimetric methods for all included children.

RESULTS

The overall results revealed that 37.04% of cases had abnormal EEG findings. Amino acid profile in autistic children showed statistically significant lower levels of aspartic acid, glycine, β-alanine, tryptophan, lysine and proline amino acids with significantly higher asparagine amino acid derivative levels among autistic patients versus the control group (p˂0.05). There were significantly higher serum ammonia levels with significantly higher total oxidant status (TOS) and oxidative stress index (OSI) values among the included autistic children vs controls (p˂0.05). There were significantly negative correlations between CARS with aspartic acid (r=-0.269, P=0.049), arginine (r= - 0.286, p= 0.036), and TAS (r= -0.341, p= 0.012), and significantly positive correlations between CARS with TOS (r=0.360, p= 0.007) and OSI (r= 0.338, p= 0.013).

CONCLUSION

Dysregulated amino acid metabolism, high ammonia and oxidative stress were prevalent among autistic children and should be considered in autism management. Still EEG records were inconclusive among autistic children, although may be helpful in assessment autism severity.

Functional Neuroimaging in Psychiatry-Aiding in Diagnosis and Guiding Treatment. What the American Psychiatric Association Does Not Know

While early efforts in psychiatry were focused on uncovering the neurobiological basis of psychiatric symptoms, they made little progress due to limited ability to observe the living brain. Today, we know a great deal about the workings of the brain; yet, none of this neurobiological awareness has translated into the practice of psychiatry. The categorical system which dominates psychiatric diagnosis and thinking fails to match up to the real world of genetics, sophisticated psychological testing, and neuroimaging. Nevertheless, the American Psychiatric Association (APA) recently published a position paper stating that neuroimaging provided no benefit to the diagnosis and treatment of psychiatric disorders. Using the diagnosis of depression as a model, we illustrate how setting aside the unrealistic expectation of a pathognomonic "fingerprint" for categorical diagnoses, we can avoid missing the biological and, therefore, treatable contributors to psychopathology which can and are visualized using functional neuroimaging. Infection, toxicity, inflammation, gut-brain dysregulation, and traumatic brain injury can all induce psychiatric manifestations which masquerade as depression and other psychiatric disorders. We review these and provide illustrative clinical examples. We further describe situations for which single photon emission computed tomography (SPECT) and positron emission tomography (PET) functional neuroimaging already meet or exceed the criteria set forth by the APA to define a neuroimaging biomarker, including the differential diagnosis of Alzheimer's disease and other dementias, the differential diagnosis of ADHD, and the evaluation of traumatic brain injury. The limitations, both real and perceived, of SPECT and PET functional neuroimaging in the field of psychiatry are also elaborated. An important overarching concept for diagnostic imaging in all its forms, including functional neuroimaging, is that imaging allows a clinician to eliminate possibilities, narrow the differential diagnosis, and tailor the treatment plan. This progression is central to any medical diagnostic process.

Protein Nutrition in Autism

Autism is a developmental disorder that affects communication and behavior. Although autism can be diagnosed at any age, it is said to be a "developmental disorder" because symptoms generally appear in the first 2 years of life. The primary cause of autism is still not clear and therapy is currently restricted to controlling behavioral abnormalities. However, emerging studies have shown a link between mitochondrial dysfunction and autism. Dietary supplements that promote mitochondrial biogenesis and inhibit the production of oxidative stress have been used to treat autism patients. Dietary adjustments in treating autism is a novel approach to suppress autistic symptoms. Supplementation with antioxidants has been found to not only inhibit cognitive decline but also improve behavioral symptoms in autism. Dietary supplements fortified with vitamins should only be given under the supervision of a physician. A wide range of nutraceuticals are under clinical trials to understand whether they physiologically target mitochondrial pathways and improve the quality of life in autism.

Developmental exposure to polychlorinated biphenyls (PCBs) in the maternal diet causes host-microbe defects in weanling offspring mice

The gut microbiota is important for maintaining homeostasis of the host. Gut microbes represent the initial site for toxicant processing following dietary exposures to environmental contaminants. The diet is the primary route of exposure to polychlorinated biphenyls (PCBs), which are absorbed via the gut, and subsequently interfere with neurodevelopment and behavior. Developmental exposures to PCBs have been linked to increased risk of neurodevelopmental disorders (NDD), including autism spectrum disorder (ASD), which are also associated with a high prevalence of gastrointestinal (GI) distress and intestinal dysbiosis. We hypothesized that developmental PCB exposure impacts colonization of the gut microbiota, resulting in GI pathophysiology, in a genetically susceptible host. Mouse dams expressing two heritable human mutations (double mutants [DM]) that result in abnormal Ca²⁺ dynamics and produce behavioral deficits (gain of function mutation in the ryanodine receptor 1 [T4826I-RYR1] and a human CGG repeat expansion [170-200 CGG repeats] in the fragile X mental retardation gene 1 [FMR1 premutation]). DM and congenic wild type (WT) controls were exposed to PCBs (0-6 mg/kg/d) in the diet starting 2 weeks before gestation and continuing through postnatal day 21 (P21). Intestinal physiology (Ussing chambers), inflammation (qPCR) and gut microbiome (16S sequencing) studies were performed in offspring mice (P28-P30). Developmental exposure to PCBs in the maternal diet caused significant mucosal barrier defects in ileum and colon (increased secretory state and tight junction permeability) of juvenile DM mice. Furthermore, PCB exposure increased the intestinal inflammatory profile (Il6, Il1β, and Il22), and resulted in dysbiosis of the gut microbiota, including altered β-diversity, in juvenile DM mice developmentally exposed to 1 mg/kg/d PCBs when compared to WT controls. Collectively, these findings demonstrate a novel interaction between PCB exposure and the gut microbiota in a genetically susceptible host that provide novel insight into environmental risk factors for neurodevelopmental disorders.

Gut-brain axis in the executive function of austism spectrum disorder

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impaired communication and social interactions, and repetitive behavioural patterns. These patterns are believed to be dysfunctional symptoms in executive processing, which impact other cognitive functions such as attention or cognitive flexibility. In recent years, several studies have shown that certain intestinal bacteria may play a role in shaping cognitive networks encompassing emotional and social domains. A microbiota-gut-brain axis is known to exist, establishing several mechanisms by which microbiota may modulate brain development, function and behaviour, including immune, endocrine and neural pathways. As the aetiology of ASD is largely unknown, some studies have shown that intestinal bacteria may be involved in its pathogenesis. The aim of this review was to focus on the role of the gut-brain axis in ASD and, specifically, on its role in executive functions. First, we summarize the relationship between the gastrointestinal and cognitive symptoms of ASD patients. In addition, we highlight the evidence that supports and emphasizes the involvement of gut microbiota, and the putative underlying mechanisms in this population. Finally, we present evidence from preclinical and clinical studies on the modulation of microbiota and their effects on cognitive symptoms, specifically in relation to executive function. In conclusion, manipulation of microbiota could be a positive intervention to improve ASD symptoms. However, more research evaluating the role of microbiota in the cognitive symptoms ASD is needed.

Can we reduce autism-related gastrointestinal and behavior problems by gut microbiota based dietary modulation? A review

Introduction: Autism is a neurodevelopmental disorder that negatively affects a child's interaction and communication with the environment. The signals between intestine, brain, and microbiota change in autism. Altering the composition of microbiota may contribute to the development of clinical symptoms. Diet is one of the most important factors influencing intestinal microbiota.Aim: This study aimed to investigate the role of intestinal microbiota in gastrointestinal (GI) and behavioral problems seen in children with autism and discuss the potential effect of diet on intestinal microbiota in reducing these problems.Methods: The database Web of Science was searched for relevant studies. The combinations of the following terms were used for the search: 'autism' or 'autistic' and 'microbiome' or 'microbiota' or 'gut bacteria' or 'gut microbiota' or 'gut microbiome.' The analysis included human studies evaluating the relationship between GI problems and/or behavioral problems and intestinal microbiota in autism in the English language with no time limitation.Results: The initial search resulted in 691 studies, with 14 studies fully meeting the inclusion criteria. In these studies, high growth rates of Clostridium histolyticum, C. perfringens, and Sutterella; high ratio of Escherichia/Shigella; and low ratio of Bacteroidetes/Firmicutes were generally related to GI problems, while relative abundance of Desulfovibrio, Clostridium spp., and Bacteroides vulgatus were associated with behavior disorders.Conclusions: Published studies on the relationship of gastrointestinal and behavioral problems with gut microbiota in autism are very limited and contradictory. The fact that the results of the studies are not consistent with each other may be explained by the differences in the age of participants, geographical region, sample size, presence of GI problems in the selected control group, and feces or biopsy samples taken from different regions of GI system. With the available information, it is not yet possible to develop a gut microbiota-based nutritional intervention to treat GI symptoms for people with autism.

Protein Supplements and Their Relation with Nutrition, Microbiota Composition and Health: Is More Protein Always Better for Sportspeople?

Sports nutrition products are developed and targeted mainly for athletes to improve their nutrient intake, performance, and muscle growth. The fastest growing consumer groups for these products are recreational sportspeople and lifestyle users. Although athletes may have elevated physiological protein requirements and they may benefit from dietary supplements, the evidence regarding the role of dietary protein and supplements in the nutrition of recreational sportspeople and sedentary populations is somewhat complex and contradictory. In high-protein diets, more undigested protein-derived constituents end up in the large intestine compared to moderate or low-protein diets, and hence, more bacterial amino acid metabolism takes place in the colon, having both positive and negative systemic and metabolic effects on the host. The aim of the present review is to summarize the impact of the high-protein products and diets on nutrition and health, in sportspeople and in sedentary consumers. We are opening the debate about the current protein intake recommendations, with an emphasis on evidence-based effects on intestinal microbiota and personalized guidelines regarding protein and amino acid supplementation in sportspeople and lifestyle consumers.

Autism Spectrum Disorders and the Gut Microbiota

In recent years, there has been an emerging interest in the possible role of the gut microbiota as a co-factor in the development of autism spectrum disorders (ASDs), as many studies have highlighted the bidirectional communication between the gut and brain (the so-called “gut-brain axis”). Accumulating evidence has shown a link between alterations in the composition of the gut microbiota and both gastrointestinal and neurobehavioural symptoms in children with ASD. The aim of this narrative review was to analyse the current knowledge about dysbiosis and gastrointestinal (GI) disorders in ASD and assess the current evidence for the role of probiotics and other non-pharmacological approaches in the treatment of children with ASD. Analysis of the literature showed that gut dysbiosis in ASD has been widely demonstrated; however, there is no single distinctive profile of the composition of the microbiota in people with ASD. Gut dysbiosis could contribute to the low-grade systemic inflammatory state reported in patients with GI comorbidities. The administration of probiotics (mostly a mixture of Bifidobacteria, Streptococci and Lactobacilli) is the most promising treatment for neurobehavioural symptoms and bowel dysfunction, but clinical trials are still limited and heterogeneous. Well-designed, randomized, placebo-controlled clinical trials are required to validate the effectiveness of probiotics in the treatment of ASD and to identify the appropriate strains, dose, and timing of treatment.

Systematic Review of Gut Microbiota and Major Depression

Background: Recently discovered relationships between the gastrointestinal microbiome and the brain have implications for psychiatric disorders, including major depressive disorder (MDD). Bacterial transplantation from MDD patients to rodents produces depression-like behaviors. In humans, case-control studies have examined the gut microbiome in healthy and affected individuals. We systematically reviewed existing studies comparing gut microbial composition in MDD and healthy volunteers. Methods: A PubMed literature search combined the terms "depression," "depressive disorder," "stool," "fecal," "gut," and "microbiome" to identify human case-control studies that investigated relationships between MDD and microbiota quantified from stool. We evaluated the resulting studies, focusing on bacterial taxa that were different between MDD and healthy controls. Results: Six eligible studies were found in which 50 taxa exhibited differences (p < 0.05) between patients with MDD and controls. Patient characteristics and methodologies varied widely between studies. Five phyla-Bacteroidetes, Firmicutes, Actinobacteria, Fusobacteria, and Protobacteria-were represented; however, divergent results occurred across studies for all phyla. The largest number of differentiating taxa were within phylum Firmicutes, in which nine families and 12 genera differentiated the diagnostic groups. The majority of these families and genera were found to be statistically different between the two groups in two identified studies. Family Lachnospiraceae differentiated the diagnostic groups in four studies (with an even split in directionality). Across all five phyla, nine genera were higher in MDD (Anaerostipes, Blautia, Clostridium, Klebsiella, Lachnospiraceae incertae sedis, Parabacteroides, Parasutterella, Phascolarctobacterium, and Streptococcus), six were lower (Bifidobacterium, Dialister, Escherichia/Shigella, Faecalibacterium, and Ruminococcus), and six were divergent (Alistipes, Bacteroides, Megamonas, Oscillibacter, Prevotella, and Roseburia). We highlight mechanisms and products of bacterial metabolism as they may relate to the etiology of depression. Conclusions: No consensus has emerged from existing human studies of depression and gut microbiome concerning which bacterial taxa are most relevant to depression. This may in part be due to differences in study design. Given that bacterial functions are conserved across taxonomic groups, we propose that studying microbial functioning may be more productive than a purely taxonomic approach to understanding the gut microbiome in depression.

Pilot study of probiotic/colostrum supplementation on gut function in children with autism and gastrointestinal symptoms

Over half of all children with autism spectrum disorders (ASD) have gastrointestinal (GI) co-morbidities including chronic constipation, diarrhea, and irritable bowel syndrome. The severity of these symptoms has been correlated with the degree of GI microbial dysbiosis. The study objective was to assess tolerability of a probiotic (Bifidobacterium infantis) in combination with a bovine colostrum product (BCP) as a source of prebiotic oligosaccharides and to evaluate GI, microbiome and immune factors in children with ASD and GI co-morbidities. This pilot study is a randomized, double blind, controlled trial of combination treatment (BCP + B. infantis) vs. BCP alone in a cross-over study in children ages 2-11 with ASD and GI co-morbidities (n = 8). This 12-week study included 5 weeks of probiotic-prebiotic supplementation, followed by a two-week washout period, and 5 weeks of prebiotic only supplementation. The primary outcome of tolerability was assessed using validated questionnaires of GI function and atypical behaviors, along with side effects. Results suggest that the combination treatment is well-tolerated in this cohort. The most common side effect was mild gassiness. Some participants on both treatments saw a reduction in the frequency of certain GI symptoms, as well as reduced occurrence of particular aberrant behaviors. Improvement may be explained by a reduction in IL-13 and TNF-α production in some participants. Although limited conclusions can be drawn from this small pilot study, the results support the need for further research into the efficacy of these treatments.

The Gut-Immune-Brain Axis in Autism Spectrum Disorders; A Focus on Amino Acids

Autism spectrum disorder (ASD) is a range of neurodevelopmental conditions that affect communication and social behavior. Besides social deficits, systemic inflammation, gastrointestinal immune-related problems, and changes in the gut microbiota composition are characteristic for people with ASD. Animal models showed that these characteristics can induce ASD-associated behavior, suggesting an intimate relationship between the microbiota, gut, immune system and the brain in ASD. Multiple factors can contribute to the development of ASD, but mutations leading to enhanced activation of the mammalian target of rapamycin (mTOR) are reported frequently. Hyperactivation of mTOR leads to deficits in the communication between neurons in the brain and to immune impairments. Hence, mTOR might be a critical factor linking the gut-brain-immune axis in ASD. Pharmacological inhibition of mTOR is shown to improve ASD-associated behavior and immune functions, however, the clinical use is limited due to severe side reactions. Interestingly, studies have shown that mTOR activation can also be modified by nutritional stimuli, in particular by amino acids. Moreover, specific amino acids are demonstrated to inhibit inflammation, improve gut barrier function and to modify the microbiota composition. In this review we will discuss the gut-brain-immune axis in ASD and explore the potential of amino acids as a treatment option for ASD, either via modification of mTOR activity, the immune system or the gut microbiota composition.

Whole Fruits and Fruit Fiber Emerging Health Effects

Less than 10% of most Western populations consume adequate levels of whole fruits and dietary fiber with typical intake being about half of the recommended levels. Evidence of the beneficial health effects of consuming adequate levels of whole fruits has been steadily growing, especially regarding their bioactive fiber prebiotic effects and role in improved weight control, wellness and healthy aging. The primary aim of this narrative review article is to examine the increasing number of health benefits which are associated with the adequate intake of whole fruits, especially fruit fiber, throughout the human lifecycle. These potential health benefits include: protecting colonic gastrointestinal health (e.g., constipation, irritable bowel syndrome, inflammatory bowel diseases, and diverticular disease); promoting long-term weight management; reducing risk of cardiovascular disease, type 2 diabetes and metabolic syndrome; defending against colorectal and lung cancers; improving odds of successful aging; reducing the severity of asthma and chronic obstructive pulmonary disease; enhancing psychological well-being and lowering the risk of depression; contributing to higher bone mineral density in children and adults; reducing risk of seborrheic dermatitis; and helping to attenuate autism spectrum disorder severity. Low whole fruit intake represents a potentially more serious global population health threat than previously recognized, especially in light of the emerging research on whole fruit and fruit fiber health benefits.