Maternal Dietary Factors and the Risk of Autism Spectrum Disorders: A Systematic Review of Existing Evidence

The Association of Prenatal Dietary Factors with Child Autism Diagnosis and Autism-Related Traits Using a Mixtures Approach: Results from the Environmental influences on Child Health Outcomes Cohort

BACKGROUND

Previous research on the role of maternal diet in relation to autism has focused on examining individual nutrient associations. Few studies have examined associations with multiple nutrients using mixtures approaches, which may better reflect true exposure scenarios.

OBJECTIVES

This study aims to examine associations of nutrient mixtures with children's autism diagnosis and trait scores within a large, diverse population.

METHODS

Participants were drawn from the United States Environmental influences on Child Health Outcomes (ECHO) consortium. Maternal prenatal diet was reported via validated food frequency questionnaires. Children's autism-related traits were measured using the Social Responsiveness Scale (SRS) and autism diagnoses were from parent reports of physician diagnosis. Bayesian kernel machine regression was used to examine the overall mixture effect and interactions between a set of 5 primary nutrients (folate, vitamin D, omega 3 and omega 6 fatty acids, and iron), adjusted for potential confounders, in relationship to child outcomes. Secondary analyses were conducted in a subset of cohorts with an expanded set of 14 nutrients. Traditional linear and logistic regression models were also analyzed for comparison of results to mixture models.

RESULTS

A total of 2614 participants drawn from 7 ECHO cohorts were included in primary analysis. Mixture analyses suggested that increasing the overall 5-nutrient mixture was associated with lower SRS scores. Individual U-shaped associations and bivariate interactions between folate and omega 3 fatty acids were suggested. In the subset included in the secondary analyses of the 14-nutrient mixture, a modest inverse trend remained, but individual nutrient associations were altered, with vitamin D demonstrating higher relative importance than other nutrients. Strong associations with autism diagnosis were not observed.

CONCLUSIONS

In this large sample, we found evidence for combined nutrient effects with broader autism-related traits. Because results for individual nutrients were sensitive to mixture components, replication of combined associations between nutrients and autism-related outcomes is needed.

Folic acid and autism: updated evidences

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition that impairs communication, socialization, and behavior. The association of ASD with folic acid has been investigated due to the importance of this vitamin for neurological health. This study is an update of the publication 'Folic acid and autism: What do we know?' and aims to systematically review studies examining the relationship between folic acid and ASD. The search resulted in 2,389 studies on folic acid and ASD, which were selected by two reviewers based on their titles and abstracts. Studies meeting the inclusion criteria were fully read. The 52 included studies involved 10,429 individuals diagnosed with ASD and assessed the intake of vitamin B6, folic acid, and vitamin B12; serum levels of these vitamins, homocysteine, and methionine; therapeutic interventions using folic acid; and the association between maternal exposure to this vitamin and the risk of ASD. The evidence of insufficient folic acid intake in most individuals with ASD remains consistent in this update. No association was found between maternal exposure to folic acid and the risk of ASD in their children. Despite observed improvements in communication, socialization, and behavior in individuals with ASD following folic acid interventions, it is crucial to consider the individuality and complexity of ASD. Given the relevance of the topic, there remains a need for more high-quality research and clinical trials characterized by rigorous methodological designs.

Prenatal Exposure to Tobacco and Childhood Cognition and Behavior: Effect Modification by Maternal Folate Intake and Breastfeeding Duration

In this exploratory analysis, we assessed whether nutrition modified the association between prenatal exposure to tobacco and childhood cognition/behavior among 366 Colorado-based mothers and their offspring (born ≥ 37 weeks with birthweights ≥ 2500 g). Interaction by folate ( 5 months, but not for shorter durations. Our findings support the need for smoking cessation campaigns throughout pregnancy and throughout the postpartum period breastfeeding to reduce neurobehavioral risks in the offspring.

Unveiling the influences of prenatal and maternal factors on the journey of an autistic child

Background

Autism Spectrum Disorder (ASD) is a complex lifelong neurodevelopmental disorder with a high and increasing global prevalence. Although the precise causes are unknown, both genetic and environmental factors, including maternal ones during pregnancy, significantly influence its development. Therefore, this study endeavors to explore the potential causes of autism, including maternal and paternal prenatal risk factors, as well as antenatal and natal maternal risk factors, and their associations with the severity of ASD in mothers of children with ASD, from February to May 2024.

Methods

At an autism center in Saudi Arabia, this cross-sectional study enrolled 168 mothers of children diagnosed with ASD. The web-based survey employs a structured questionnaire to gather comprehensive prenatal, natal, and demographic data. The collected data was coded and analyzed using suitable tests.

Results

The majority of the surveyed 168 mothers with autistic children reported having autism spectrum disorder (43.8%), moderate autism (31.9%), mild autism (15.6%), and severe autism (8.8%). Most autistic children had a history of one or both maternal and/or paternal antenatal exposures: 79.2% had soft drink consumption, 35.1% smoked, 24.4% had chronic physical diseases, and 20.8% had psychological disease. Regarding maternal antenatal conditions, 37% had a history of recurrent infection, 29.2% had anemia, 15.5% had a history of threatened abortion or bleeding, as well as exposure to air pollution, and 22 (13.1%) had a history of gestational diabetes. Significant (p <0.05) predictors of severe autism were gestational diabetes aOR 4.553 (95% CI: [1.518, 14.25], birth oxygen desaturation 4.142 (95% CI: [1.437, 12.45]. Furthermore, the likelihood of classifying a child's ASD as severe increases by 7.1% with each year of age1.071 (95% CI: [1.002, 1.15].

Conclusion

ASD is a prevalent health condition that has many interrelationships with prenatal, maternal (medical, environmental, and psychosocial factors), and natal conditions. Prospective studies are essential for understanding and addressing these ASD risk factors.

Folate prevents the autism-related phenotype caused by developmental pyrethroid exposure in prairie voles

Neurodevelopmental disorders (NDDs) have dramatically increased in prevalence to an alarming one in six children, and yet both causes and preventions remain elusive. Recent human epidemiology and animal studies have implicated developmental exposure to pyrethroid pesticides, one of the most common classes of pesticides in the US, as an environmental risk factor for autism and neurodevelopmental disorders. Our previous research has shown that low-dose chronic developmental pyrethroid exposure (DPE) changes folate metabolites in the adult mouse brain. We hypothesize that DPE acts directly on molecular targets in the folate metabolism pathway, and that high-dose maternal folate supplementation can prevent or reduce the biobehavioral effects of DPE. We exposed pregnant prairie vole dams chronically to vehicle or low-dose deltamethrin (3 mg/kg/3 days) with or without high-dose folate supplementation (methylfolate, 5 mg/kg/3 days). The resulting DPE offspring showed broad deficits in five behavioral domains relevant to neurodevelopmental disorders (including the social domain); increased plasma folate concentrations; and increased neural expression of SHMT1, a folate cycle enzyme. Maternal folate supplementation prevented most of the behavioral phenotypes (except for repetitive behaviors) and caused potentially compensatory changes in neural expression of FOLR1 and MTHFR, two folate-related proteins. We conclude that DPE causes neurodevelopmental disorder-relevant behavioral deficits; DPE directly alters aspects of folate metabolism; and preventative interventions targeting folate metabolism are effective in reducing, but not eliminating, the behavioral effects of DPE.

Maternal Dietary Patterns During Pregnancy and Child Autism-Related Traits in the Environmental Influences on Child Health Outcomes Consortium

We examined relationships between prenatal dietary patterns and child autism-related outcomes, including parent-reported clinician diagnoses of autism spectrum disorder (ASD) and Social Responsiveness Scale (SRS-2) scores, in up to 6084 participants (with analytic samples ranging from 1671 to 4128 participants) from 14 cohorts in the Environmental Influences on Child Health Outcomes (ECHO) consortium. Associations between quartiles of the Healthy Eating Index (HEI-2015), the Alternative Healthy Eating Index modified for Pregnancy (AHEI-P), and the Empirical Dietary Inflammatory Pattern (EDIP), calculated based on reported prenatal diet, and outcomes were examined using crude and multivariable regression (quantile for SRS scores and logistic for diagnosis). In adjusted models, the higher quartile of prenatal HEI score was associated with lower SRS scores (Q4 vs. Q1 β for median quantile = -3.41 95% CI = -5.15, -1.26). A similar association was observed for the AHEI-P score when adjusting for total calories (Q4 vs. Q1 β = -2.52 95% -4.59, -0.45). There were no significant associations of prenatal diet with ASD diagnosis. Findings from this large U.S.-based study do not suggest strong associations between prenatal dietary patterns and ASD-related outcomes, although subtle associations with broader traits suggest the need to further consider how prenatal diet may relate to ASD-related phenotypes.

Dysregulation of miR-146a in human milk of mothers having children with autism

Autism spectrum disorder (ASD) is a set of neurobehavioral manifestations that impose poor social interaction and stereotyped repetitive patterns. Several mircoRNA (miRNA) dysregulations underpin ASD pathophysiology via impairing the neurogenic niches. For instance, miR-146a and miR-106 differential expressions are linked to deregulation of ASD-related genes and the severity of clinical symptoms, respectively. Breastfeeding provides newborns with many bioactive compounds that support their neurodevelopment including miRNA. Our pilot study evaluated the expression pattern of miR-106a and miR-146a in human milk (HM) of nursing mothers (n = 36) having autistic children compared to age-matched counterparts (n = 36) with neurotypical children as controls. Under sterile conditions, breast milk samples were collected using manual sucking pumps and centrifuged to separate the fat layer. Total RNA was extracted from the lipid fraction, and the expression profiles of both miR-106a and miR-146a were evaluated using quantitative real-time polymerase chain reaction. Among the test group, we reported some factors that were previously linked to HM miRNA perturbations: gestational diabetes, hypertension, and cesarean delivery. HM miR-106a showed comparable expression levels in both mother groups (p = 0.8681), whereas HM miR-146a was significantly downregulated in mothers with autistic children compared to controls (p = 0.0399). Alternatively, HM miR-106 levels were positively associated with two ASD clinical parameters: Childhood Autism Rating Scale (CARS) and communication and language domain of Autism Diagnostic Interview-Revised (ADI-R) (r = 0.6452, p = 0.0003 and r = 0.3958, p = 0.0410, respectively). The receiver operating characteristic (ROC) curves of both maternal HM miR-106a and miR-146a showed poor fitness as predictive biomarkers for ASD. Our findings suggest that the miR-146a differential expression in ASD children may originate at infancy during the lactation period. Thus, maternal pre- and postnatal health care is critical to maintain optimal miRNome in breast milk.

Disrupted Prenatal Metabolism May Explain the Etiology of Suboptimal Neurodevelopment: A Focus on Phthalates and Micronutrients and their Relationship to Autism Spectrum Disorder

Pregnancy is a time of high metabolic coordination, as maternal metabolism adapts to support the growing fetus. Many of these changes are coordinated by the placenta, a critical fetal endocrine organ and the site of maternal-fetal crosstalk. Dysregulation in maternal and placental metabolism during pregnancy has been linked to adverse outcomes, including altered neurodevelopment. Autism spectrum disorder (ASD) is a neurodevelopmental disorder linked to metabolic alterations in both children and their mothers. Prenatal environmental exposures have been linked to risk of ASD through dysregulated maternal, placental, and fetal metabolism. In this review, we focus on recent studies investigating the associations between prenatal metabolism in the maternal-placental-fetal unit and the impact of prenatal environmental exposures to phthalates and micronutrients on ASD risk. By identifying the mechanisms through which phthalates and other ubiquitous endocrine disrupting chemicals influence development, and how nutritional interventions can impact those mechanisms, we can identify promising ways to prevent suboptimal neurodevelopment.

Maternal high-fat or low-protein diets promote autism-related behavior and altered social behavior within groups in offspring male mice

Maternal malnutrition has been associated with neurodevelopmental deficits and long-term implications on the offspring's health and behavior. Here, we investigated the effects of maternal low-protein diet (LPD) or obesity-inducing maternal high-fat diet (HFD) on dyadic social interactions, group organization and autism-related behaviors in mice. We found that maternal HFD induced an autism-related behavioral phenotype in the male offspring, including a robust decrease in sociability, increased aggression, cognitive rigidity and repetitive behaviors. Maternal LPD led to a milder yet significant effect on autism-related symptoms, with no effects on olfactory-mediated social behavior. Under naturalistic conditions in a group setting, this manifested in altered behavioral repertoires, increased magnitude in dominance relations, and reduced interactions with novel social stimuli in the HFD male offspring, but not in the LPD offspring. Finally, we found HFD-induced transcriptomic changes in the olfactory bulbs of the male offspring. Together, our findings show that maternal malnutrition induces long-lasting effects on aggression and autism-related behaviors in male offspring, and potential impairments in brain regions processing chemosensory signals.

Prenatal air pollution and children's autism traits score: Examination of joint associations with maternal intake of vitamin D, methyl donors, and polyunsaturated fatty acids using mixture methods

Background

Maternal nutrient intake may moderate associations between environmental exposures and children's neurodevelopmental outcomes, but few studies have assessed joint effects. We aimed to evaluate whether prenatal nutrient intake influences the association between air pollutants and autism-related trait scores.

Methods

We included 126 participants from the EARLI (Early Autism Risk Longitudinal Investigation, 2009-2012) cohort, which followed US pregnant mothers who previously had a child with autism. Bayesian kernel machine regression and traditional regression models were used to examine joint associations of prenatal nutrient intake (vitamins D, B12, and B6; folate, choline, and betaine; and total omega 3 and 6 polyunsaturated fatty acids, reported via food frequency questionnaire), air pollutant exposure (particulate matter <2.5 μm [PM2.5], nitrogen dioxide [NO2], and ozone [O3], estimated at the address level), and children's autism-related traits (measured by the Social Responsiveness Scale [SRS] at 36 months).

Results

Most participants had nutrient intakes and air pollutant exposures that met US standards. Bayesian kernel machine regression mixture models and traditional regression models provided little evidence of individual or joint associations of nutrients and air pollutants with SRS scores or of an association between the overall mixture and SRS scores.

Conclusion

In this cohort with a high familial likelihood of autism, we did not observe evidence of joint associations between air pollution exposures and nutrient intake with autism-related traits. Future work should examine the use of these methods in larger, more diverse samples, as our results may have been influenced by familial liability and/or relatively high nutrient intakes and low air pollutant exposures.

Food, nutrition, and autism: from soil to fork

Food and nutrition-related factors have the potential to impact development of autism spectrum disorder (ASD) and quality of life for people with ASD, but gaps in evidence exist. On 10 November 2022, Tufts University's Friedman School of Nutrition Science and Policy and Food and Nutrition Innovation Institute hosted a 1-d meeting to explore the evidence and evidence gaps regarding the relationships of food and nutrition with ASD. This meeting report summarizes the presentations and deliberations from the meeting. Topics addressed included prenatal and child dietary intake, the microbiome, obesity, food-related environmental exposures, mechanisms and biological processes linking these factors and ASD, food-related social factors, and data sources for future research. Presentations highlighted evidence for protective associations with prenatal folic acid supplementation and ASD development, increases in risk of ASD with maternal gestational obesity, and the potential for exposure to environmental contaminants in foods and food packaging to influence ASD development. The importance of the maternal and child microbiome in ASD development or ASD-related behaviors in the child was reviewed, as was the role of discrimination in leading to disparities in environmental exposures and psychosocial factors that may influence ASD. The role of child diet and high prevalence of food selectivity in children with ASD and its association with adverse outcomes were also discussed. Priority evidence gaps identified by participants include further clarifying ASD development, including biomarkers and key mechanisms; interactions among psychosocial, social, and biological determinants; interventions addressing diet, supplementation, and the microbiome to prevent and improve quality of life for people with ASD; and mechanisms of action of diet-related factors associated with ASD. Participants developed research proposals to address the priority evidence gaps. The workshop findings serve as a foundation for future prioritization of scientific research to address evidence gaps related to food, nutrition, and ASD.

A case-control study on pre-, peri-, and neonatal risk factors associated with autism spectrum disorder among Armenian children

We aimed to investigate the role of pre-, peri- and neonatal risk factors in the development of autism spectrum disorder (ASD) among Armenian children with the goal of detecting and addressing modifiable risk factors to reduce ASD incidence. For this purpose a retrospective case-control study using a random proportional sample of Armenian children with ASD to assess associations between various factors and ASD was conducted. The study was approved by the local ethical committee, and parental written consent was obtained. A total of 168 children with ASD and 329 controls were included in the analysis. Multivariable logistic regression analysis revealed that male gender, maternal weight gain, use of MgB6, self-reported stress during the pregnancy, pregnancy with complications, as well as use of labor-inducing drugs were associated with a significant increase in the odds of ASD, whereas Duphaston use during pregnancy, the longer interpregnancy interval and birth height were associated with decreased odds of ASD. These findings are pertinent as many identified factors may be preventable or modifiable, underscoring the importance of timely and appropriate public health strategies aimed at disease prevention in pregnant women to reduce ASD incidence.

Striatal insights: a cellular and molecular perspective on repetitive behaviors in pathology

Animals often behave repetitively and predictably. These repetitive behaviors can have a component that is learned and ingrained as habits, which can be evolutionarily advantageous as they reduce cognitive load and the expenditure of attentional resources. Repetitive behaviors can also be conscious and deliberate, and may occur in the absence of habit formation, typically when they are a feature of normal development in children, or neuropsychiatric disorders. They can be considered pathological when they interfere with social relationships and daily activities. For instance, people affected by obsessive-compulsive disorder, autism spectrum disorder, Huntington's disease and Gilles de la Tourette syndrome can display a wide range of symptoms like compulsive, stereotyped and ritualistic behaviors. The striatum nucleus of the basal ganglia is proposed to act as a master regulator of these repetitive behaviors through its circuit connections with sensorimotor, associative, and limbic areas of the cortex. However, the precise mechanisms within the striatum, detailing its compartmental organization, cellular specificity, and the intricacies of its downstream connections, remain an area of active research. In this review, we summarize evidence across multiple scales, including circuit-level, cellular, and molecular dimensions, to elucidate the striatal mechanisms underpinning repetitive behaviors and offer perspectives on the implicated disorders. We consider the close relationship between behavioral output and transcriptional changes, and thereby structural and circuit alterations, including those occurring through epigenetic processes.

Eating disorder in children: Impact on quality of life, with a spotlight on autism spectrum disorder

Eating behavior, which includes eating habits and preferences, frequency of eating, and other features related to diet, is a major characteristic not only of a person's nutritional status, but also of health in general. In recent years, the prevalence of eating disorders in children has tended to increase; they also require cross-system approaches in diagnosis by a variety of specialists and correction requires appropriate selection of optimal methods. Maladaptive eating attitudes formed at an early age can contribute to the formation of eating disorders, which can lead to or worsen various neuropsychiatric diseases, digestive diseases, and other related conditions. In children with autism spectrum disorder (ASD), eating disorders often appear earlier than other major symptoms of the condition. However, the clinical manifestations of eating disorders in children with ASD are varied and differ in severity and duration, whereas these disorders in neurotypical children might present as short-lived and may not lead to serious consequences. Nevertheless, cases of progressive eating disorders accompanied by a child presenting as under- or overweight and/or with macronutrient and micronutrient deficiencies cannot be excluded. Given the high prevalence of eating disorders in children, many researchers have highlighted the lack of a valid and universally accepted instruments to assess atypical eating behaviors in this population. Therefore, in this review, we wanted to highlight the problems and causes of eating disorders in children, and also to analyze the existing approaches to the validation of these problems, taking into account the existing behavioral features in children with ASD.

Lack of Biological Plausibility and Major Methodological Issues Cast Doubt on the Association between Aspartame and Autism. Comment on Fowler et al. Daily Early-Life Exposures to Diet Soda and Aspartame Are Associated with Autism in Males: A Case-Control Study. Nutrients 2023, 15, 3772

The case-control study by Fowler et al [...].

Correlation analysis of maternal condition during pregnancy with head circumference and autism spectrum disorder: A propensity score-matched study

To determine whether health status during pregnancy is associated with autism spectrum disorder (ASD) and abnormal head circumference (HC) in the offspring. This study included 41 Han children with ASD who visited the Children's Health Clinic of the Second Hospital of Shandong University between March 2018 and February 2019, and 264 Han children with typical development (TD) who visited the clinic during the same period. Physical measurements were performed on the children. The questionnaire obtained information on maternal risk factors that may be related to the increased risk of ASD and folic acid (FA) supplementation. We designed an observational case-control study using propensity score matching and multivariate logistic regression analysis. The incidence of macrocephaly in the ASD group was 22.0%, significantly higher than that in the TD group (1.8%). The incidence of microcephaly in the ASD group was 17.1% (n = 7), significantly higher than that in the TD group (1.8%). The differences between the comparisons were statistically significant. Maternal FA supplementation during pregnancy was significantly associated with ASD (P < .05), with an odds ratio (95% confidence interval of 3.69 (1.76, 7.76)). Also was associated with macrocephaly (P < .05), odds ratio (95% confidence interval) were 8.13 (1.63, 40.61) and 4.16 (1.18, 14.60), respectively. The incidence of abnormal HC was higher in the ASD group than that in the TD group. Maternal FA supplementation during pregnancy may be negatively associated with the occurrence of ASD and abnormal HC in the offspring. Further examination of the role of maternal health status in the etiology of ASD is recommended.

Neurodevelopmental and Neuropsychiatric Disorders

This chapter will focus on microglial involvement in neurodevelopmental and neuropsychiatric disorders, particularly autism spectrum disorder (ASD), schizophrenia and major depressive disorder (MDD). We will describe the neuroimmune risk factors that contribute to the etiopathology of these disorders across the lifespan, including both in early life and adulthood. Microglia, being the resident immune cells of the central nervous system, could play a key role in triggering and determining the outcome of these disorders. This chapter will review preclinical and clinical findings where microglial morphology and function were examined in the contexts of ASD, schizophrenia and MDD. Clinical evidence points out to altered microglial morphology and reactivity, as well as increased expression of pro-inflammatory cytokines, supporting the idea that microglial abnormalities are involved in these disorders. Indeed, animal models for these disorders found altered microglial morphology and homeostatic functions which resulted in behaviours related to these disorders. Additionally, as microglia have emerged as promising therapeutic targets, we will also address in this chapter therapies involving microglial mechanisms for the treatment of neurodevelopmental and neuropsychiatric disorders.

Environmental Risk Factors in Autism Spectrum Disorder: A Narrative Review

Existing evidence indicates that environmental factors might contribute up to 50% of the variance in autism spectrum disorder (ASD) risk. This structured narrative review offers a comprehensive synthesis of current knowledge on environmental risk factors in ASD, including evaluation of conflicting evidence, exploration of underlying mechanisms, and suggestions for future research directions. Analysis of diverse epidemiological investigations indicates that certain environmental factors, including advanced parental age, preterm birth, delivery complications, and exposure to toxic metals, drugs, air pollutants, and endocrine-disrupting chemicals, are linked to an increased ASD risk through various mechanisms such as oxidative stress, inflammation, hypoxia, and its consequences, changes in neurotransmitters, disruption of signaling pathways and some others. On the other hand, pregnancy-related factors such as maternal diabetes, maternal obesity, and caesarian section show a weaker association with ASD risk. At the same time, other environmental factors, such as vaccination, maternal smoking, or alcohol consumption, are not linked to the risk of ASD. Regarding nutritional elements data are inconclusive. These findings highlight the significance of environmental factors in ASD etiology and emphasize that more focused research is needed to target the risk factors of ASD. Environmental interventions targeting modifiable risk factors might offer promising avenues for ASD prevention and treatment.

The early life exposome and autism risk: a role for the maternal microbiome?

Autism spectrum disorders (ASD) are highly heritable, heterogeneous neurodevelopmental disorders characterized by clinical presentation of atypical social, communicative, and repetitive behaviors. Over the past 25 years, hundreds of ASD risk genes have been identified. Many converge on key molecular pathways, from translational control to those regulating synaptic structure and function. Despite these advances, therapeutic approaches remain elusive. Emerging data unearthing the relationship between genetics, microbes, and immunity in ASD suggest an integrative physiology approach could be paramount to delivering therapeutic breakthroughs. Indeed, the advent of large-scale multi-OMIC data acquisition, analysis, and interpretation is yielding an increasingly mechanistic understanding of ASD and underlying risk factors, revealing how genetic susceptibility interacts with microbial genetics, metabolism, epigenetic (re)programming, and immunity to influence neurodevelopment and behavioral outcomes. It is now possible to foresee exciting advancements in the treatment of some forms of ASD that could markedly improve quality of life and productivity for autistic individuals. Here, we highlight recent work revealing how gene X maternal exposome interactions influence risk for ASD, with emphasis on the intrauterine environment and fetal neurodevelopment, host-microbe interactions, and the evolving therapeutic landscape for ASD.

Daily Early-Life Exposures to Diet Soda and Aspartame Are Associated with Autism in Males: A Case-Control Study

Since its introduction, aspartame-the leading sweetener in U.S. diet sodas (DS)-has been reported to cause neurological problems in some users. In prospective studies, the offspring of mothers who consumed diet sodas/beverages (DSB) daily during pregnancy experienced increased health problems. We hypothesized that gestational/early-life exposure to ≥1 DS/day (DSearly) or equivalent aspartame (ASPearly: ≥177 mg/day) increases autism risk. The case-control Autism Tooth Fairy Study obtained retrospective dietary recalls for DSB and aspartame consumption during pregnancy/breastfeeding from the mothers of 235 offspring with autism spectrum disorder (ASD: cases) and 121 neurotypically developing offspring (controls). The exposure odds ratios (ORs) for DSearly and ASPearly were computed for autism, ASD, and the non-regressive conditions of each. Among males, the DSearly odds were tripled for autism (OR = 3.1; 95% CI: 1.02, 9.7) and non-regressive autism (OR = 3.5; 95% CI: 1.1, 11.1); the ASPearly odds were even higher: OR = 3.4 (95% CI: 1.1, 10.4) and 3.7 (95% CI: 1.2, 11.8), respectively (p < 0.05 for each). The ORs for non-regressive ASD in males were almost tripled but were not statistically significant: DSearly OR = 2.7 (95% CI: 0.9, 8.4); ASPearly OR = 2.9 (95% CI: 0.9, 8.8). No statistically significant associations were found in females. Our findings contribute to the growing literature raising concerns about potential offspring harm from maternal DSB/aspartame intake in pregnancy.

Examining Prenatal Dietary Factors in Association with Child Autism-Related Traits Using a Bayesian Mixture Approach: Results from 2 United States Cohorts

Background

Prior work has suggested relationships between prenatal intake of certain nutrients and autism.

Objectives

We examined a broad set of prenatal nutrients and foods using a Bayesian modeling approach.

Methods

Participants were drawn from the Early Autism Risks Longitudinal Investigation (n = 127), a cohort following women with a child with autism through a subsequent pregnancy. Participants were also drawn from the Nurses' Health Study II (NHSII, n = 713), a cohort of United States female nurses, for comparison analyses. In both studies, information on prospectively reported prenatal diet was drawn from food frequency questionnaires, and child autism-related traits were measured by the Social Responsiveness Scale (SRS). Bayesian kernel machine regression was used to examine the combined effects of several nutrients with neurodevelopmental relevance, including polyunsaturated fatty acids (PUFAs), iron, zinc, vitamin D, folate, and other methyl donors, and separately, key food sources of these, in association with child SRS scores in crude and adjusted models.

Results

In adjusted analyses, the overall mixture effects of nutrients in Early Autism Risks Longitudinal Investigation and foods in both cohorts on SRS scores were not observed, though there was some suggestion of decreasing SRS scores with increasing overall nutrient mixture in NHSII. No associations were observed with folate within the context of this mixture, but holding other nutrients fixed, n-6 PUFAs were associated with lower SRS scores in NHSII. In both cohorts, lower SRS scores were observed with higher intake of some groupings of vegetables, though for differing types of vegetables across cohorts, and some vegetable groups were associated with higher SRS scores in NHSII.

Conclusions

Our work extends prior research and suggests the need to further consider prenatal dietary factors from a combined effects perspective. In addition, findings here point to potential differences in nutrient associations based on a family history of autism, which suggests the need to consider gene interactions in future work.

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.

Water-soluble vitamin insufficiency, deficiency and supplementation in children and adolescents with a psychiatric disorder: a systematic review and meta-analysis

Nutrition is fundamental for brain development, but relatively little is known about water-soluble vitamin (WSV) levels and the effect of supplementation on psychiatry symptoms in children and adolescents (CAD) with psychiatric disorders. Our team systematically reviewed all studies concerning WSV abnormalities or supplementation in CAD with any psychiatric disorder. We searched for original studies published between 1990 and 15/05/2020 which were not based on retrospective chart review and which included WSV blood level measurements or investigated the effect of WSV supplementation on psychiatric symptoms in psychiatric patients aged 18 or under. Forty-two articles were included, 69% of which (N = 29) examined Autism Spectrum Disorders (ASD), with most of these assessing folate or vitamin B₁₂ supplementation (N = 22, 75.9% of ASD studies). Meta-analyses showed significantly lower vitamin B₁₂ levels in ASD and ADHD patients vs. healthy controls (HC), while folate levels were higher in ADHD patients vs. HC. Most of the studies (9/10, 90%) showed a decrease in symptoms as measured by clinical scales after supplementation. There was significant heterogeneity between the studies, however many found different types of vitamin abnormalities in CAD with psychiatric disorders.

The Rationale for Vitamin, Mineral, and Cofactor Treatment in the Precision Medical Care of Autism Spectrum Disorder

Children with autism spectrum disorder may exhibit nutritional deficiencies due to reduced intake, genetic variants, autoantibodies interfering with vitamin transport, and the accumulation of toxic compounds that consume vitamins. Importantly, vitamins and metal ions are essential for several metabolic pathways and for neurotransmitter functioning. The therapeutic benefits of supplementing vitamins, minerals (Zinc, Magnesium, Molybdenum, and Selenium), and other cofactors (coenzyme Q10, alpha-lipoic acid, and tetrahydrobiopterin) are mediated through their cofactor as well as non-cofactor functions. Interestingly, some vitamins can be safely administered at levels far above the dose typically used to correct the deficiency and exert effects beyond their functional role as enzyme cofactors. Moreover, the interrelationships between these nutrients can be leveraged to obtain synergistic effects using combinations. The present review discusses the current evidence for using vitamins, minerals, and cofactors in autism spectrum disorder, the rationale behind their use, and the prospects for future use.

Distinct effects of interleukin-6 and interferon-γ on differentiating human cortical neurons

Translational evidence suggests that cytokines involved in maternal immune activation (MIA), such as interleukin-6 (IL-6) and interferon-γ (IFN-γ), can cross the placenta, injure fetal brain, and predispose to neuropsychiatric disorders. To elaborate developmental neuronal sequelae of MIA, we differentiated human pluripotent stem cells to cortical neurons over a two-month period, exposing them to IL-6 or IFN-γ. IL-6 impacted expression of genes regulating extracellular matrix, actin cytoskeleton and TGF-β signaling while IFN-γ impacted genes regulating antigen processing, major histocompatibility complex and endoplasmic reticulum biology. IL-6, but not IFN-γ, altered mitochondrial respiration while IFN-γ, but not IL-6, induced reduction in dendritic spine density. Pre-treatment with folic acid, which has known neuroprotective and anti-inflammatory properties, ameliorated IL-6 effects on mitochondrial respiration and IFN-γ effects on dendritic spine density. These findings suggest distinct mechanisms for how fetal IL-6 and IFN-γ exposure influence risk for neuropsychiatric disorders, and how folic acid can mitigate such risk.

Maternal Dietary Patterns during Pregnancy and Child Autism-Related Traits: Results from Two US Cohorts

We examined the relationship between maternal intake of established dietary patterns and child autism-related outcomes in two prospective cohorts in the United States. Participants were drawn from the Early Autism Risk Longitudinal Investigation (EARLI, n = 154) and the Nurses' Health Study II (NHSII, n = 727). Dietary information was collected via food frequency questionnaires (FFQs) and used to calculate the empirical dietary inflammatory pattern (EDIP), Alternative Healthy Eating Index (AHEI), Western and Prudent dietary patterns, and the alternative Mediterranean Diet (aMED) score. Primary analyses examined associations with continuous autism-related traits as measured by the Social Responsiveness Scale (SRS), and secondary analyses with autism spectrum disorder (ASD) diagnosis. We used crude and multivariable quantile regression fixed at the 50th percentile to examine associations between quartiles of dietary patterns and SRS scores, and logistic regression to examine associations with ASD diagnosis. There was suggestion of a positive association with the Western diet (Q4 vs. Q1, ß = 11.19, 95% CI: 3.30, 19.90) in EARLI, though the association was attenuated with adjustment for total energy intake, and no clear associations were observed with other dietary patterns and ASD diagnosis or SRS scores. Further work is needed to better understand the role of maternal dietary patterns in ASD and related outcomes.

Long-term health outcomes of children born to mothers with hyperemesis gravidarum: a systematic review and meta-analysis

OBJECTIVE

Hyperemesis gravidarum is characterized by severe nausea and vomiting in pregnancy, frequently resulting in severe maternal nutritional deficiency. Maternal undernutrition is associated with adverse offspring health outcomes. Whether hyperemesis gravidarum permanently affects offspring health remains unclear. This review aimed to evaluate the effects of maternal hyperemesis gravidarum on offspring health.

DATA SOURCES

MEDLINE and Embase were searched from inception to September 6, 2021.

STUDY ELIGIBILITY CRITERIA

Studies reporting on health at any age beyond the perinatal period of children born to mothers with hyperemesis gravidarum were included.

METHODS

Two reviewers independently selected studies and extracted data. The Newcastle-Ottawa Quality Assessment Scale was used to assess risk of bias. We conducted a narrative synthesis and meta-analysis where possible. In meta-analyses with high heterogeneity (I²>75%), we did not provide a pooled odds ratio.

RESULTS

Nineteen studies were included in this systematic review (n=1,814,785 offspring). Meta-analysis (n=619, 2 studies: 1 among adolescents and 1 among adults) showed that hyperemesis gravidarum was associated with anxiety disorder (odds ratio, 1.74; 95% confidence interval, 1.04-2.91; I², 0%) and sleep problems in offspring (odds ratio, 2.94; 95% confidence interval, 1.25-6.93; I², 0%). Hyperemesis gravidarum was associated with testicular cancer in male offspring aged up to 40 years on meta-analysis (5 studies, n=20,930 offspring), although heterogeneity was observed on the basis of a wide 95% prediction interval (odds ratio, 1.60; 95% confidence interval, 1.07-2.39; I², 0%; 95% prediction interval, 0.83-3.08). All 6 studies reporting on attention deficit (hyperactivity) disorder and autism spectrum disorder reported an increase among children of mothers with hyperemesis gravidarum in comparison with children of unaffected mothers. Meta-analysis showed high heterogeneity, precluding us from reporting a pooled odds ratio. Most studies reporting on cognitive and motor problems found an increase among hyperemesis gravidarum-exposed children. One study investigated brain structure and found smaller cortical volumes and areas among children from hyperemesis gravidarum-affected pregnancies than among those from unaffected pregnancies. Studies evaluating anthropometry and cardiometabolic disease risk of hyperemesis gravidarum-exposed children had inconsistent findings.

CONCLUSION

Our systematic review showed that maternal hyperemesis gravidarum is associated with small increases in adverse health outcomes among children, including neurodevelopmental disorders, mental health disorders, and possibly testicular cancer, although evidence is based on few studies of low quality.

Prenatal Diet as a Modifier of Environmental Risk Factors for Autism and Related Neurodevelopmental Outcomes

PURPOSE OF REVIEW

Environmental chemicals and toxins have been associated with increased risk of impaired neurodevelopment and specific conditions like autism spectrum disorder (ASD). Prenatal diet is an individually modifiable factor that may alter associations with such environmental factors. The purpose of this review is to summarize studies examining prenatal dietary factors as potential modifiers of the relationship between environmental exposures and ASD or related neurodevelopmental outcomes.

RECENT FINDINGS

Twelve studies were identified; five examined ASD diagnosis or ASD-related traits as the outcome (age at assessment range: 2-5 years) while the remainder addressed associations with neurodevelopmental scores (age at assessment range: 6 months to 6 years). Most studies focused on folic acid, prenatal vitamins, or omega-3 fatty acids as potentially beneficial effect modifiers. Environmental risk factors examined included air pollutants, endocrine disrupting chemicals, pesticides, and heavy metals. Most studies took place in North America. In 10/12 studies, the prenatal dietary factor under study was identified as a significant modifier, generally attenuating the association between the environmental exposure and ASD or neurodevelopment. Prenatal diet may be a promising target to mitigate adverse effects of environmental exposures on neurodevelopmental outcomes. Further research focused on joint effects is needed that encompasses a broader variety of dietary factors, guided by our understanding of mechanisms linking environmental exposures with neurodevelopment. Future studies should also aim to include diverse populations, utilize advanced methods to optimize detection of novel joint effects, incorporate consideration of timing, and consider both synergistic and antagonistic potential of diet.

Dynamic and Systemic Perspective in Autism Spectrum Disorders: A Change of Gaze in Research Opens to A New Landscape of Needs and Solutions

The first step for a harmonious bio-psycho-social framework in approaching autism spectrum disorders (ASD) is overcoming the conflict between the biological and the psychosocial perspective. Biological research can provide clues for a correct approach to clinical practice, assuming that it would lead to the conceptualization of a pathogenetic paradigm able to account for epidemiologic and clinical findings. The upward trajectory in ASD prevalence and the systemic involvement of other organs besides the brain suggest that the epigenetic paradigm is the most plausible one. The embryo-fetal period is the crucial window of opportunity for keeping neurodevelopment on the right tracks, suggesting that women's health in pregnancy should be a priority. Maladaptive molecular pathways beginning in utero, in particular, a vicious circle between the immune response, oxidative stress/mitochondrial dysfunction, and dysbiosis-impact neurodevelopment and brain functioning across the lifespan and are the basis for progressive multisystemic disorders that account for the substantial health loss and the increased mortality in ASD. Therefore, the biological complexity of ASD and its implications for health requires the enhancement of clinical skills on these topics, to achieve an effective multi-disciplinary healthcare model. Well-balanced training courses could be a promising starting point to make a change.

Plasma unmetabolized folic acid in pregnancy and risk of autistic traits and language impairment in antiseizure medication-exposed children of women with epilepsy

BACKGROUND

Fetal exposure to unmetabolized folic acid (UMFA) during pregnancy may be associated with adverse neurodevelopment. Antiseizure medication (ASM) may interact with folate metabolism. Women with epilepsy using ASM are often recommended high-dose folic acid supplement use during pregnancy.

OBJECTIVES

The aim was to determine the association between UMFA concentrations in pregnant women with epilepsy using ASM and risk of autistic traits or language impairment in their children aged 1.5-8 y.

METHODS

We included children of women with epilepsy using ASM and with plasma UMFA measurement enrolled in the Norwegian Mother, Father, and Child Cohort Study (MoBa). Data on ASM use, folic acid supplement use, autistic traits, and language impairment were obtained from parent-reported questionnaires during pregnancy and when the child was 1.5, 3, 5, and 8 y old. Plasma UMFA concentrations were measured during gestational weeks 17-19.

RESULTS

A total of 227 ASM-exposed children of 203 women with epilepsy were included. Response rates at ages 1.5, 3, 5, and 8 y were 67% (n = 151), 54% (n = 122), 36% (n = 82), and 37% (n = 85), respectively. For 208 (94%) children, the mother reported intake of folic acid supplement. There was no association between UMFA concentrations and autistic traits score in the adjusted multiple regression analyses at age 3 y (unstandardized B: -0.01; 95% CI: -0.03, 0.004) or 8 y (unstandardized B: 0.01; 95% CI: -0.02, 0.03). Children exposed to UMFA had no increased risk of autistic traits at age 3 y [adjusted OR (aOR): 0.98; 95% CI: 0.2, 4.2] or 8 y (aOR: 0.1; 95% CI: 0.01, 1.4) compared with unexposed children. We found no association between UMFA concentrations and language impairment in children aged 1.5-8 y.

CONCLUSIONS

Our findings do not support any adverse neurodevelopmental effects of UMFA exposure in utero in children of women with epilepsy using ASM.

Towards Tailored Gut Microbiome-Based and Dietary Interventions for Promoting the Development and Maintenance of a Healthy Brain

Mental health is determined by a complex interplay between the Neurological Exposome and the Human Genome. Multiple genetic and non-genetic (exposome) factors interact early in life, modulating the risk of developing the most common complex neurodevelopmental disorders (NDDs), with potential long-term consequences on health. To date, the understating of the precise etiology underpinning these neurological alterations, and their clinical management pose a challenge. The crucial role played by diet and gut microbiota in brain development and functioning would indicate that modulating the gut-brain axis may help protect against the onset and progression of mental-health disorders. Some nutritional deficiencies and gut microbiota alterations have been linked to NDDs, suggesting their potential pathogenic implications. In addition, certain dietary interventions have emerged as promising alternatives or adjuvant strategies for improving the management of particular NDDs, at least in particular subsets of subjects. The gut microbiota can be a key to mediating the effects of other exposome factors such as diet on mental health, and ongoing research in Psychiatry and Neuropediatrics is developing Precision Nutrition Models to classify subjects according to a diet response prediction based on specific individual features, including microbiome signatures. Here, we review current scientific evidence for the impact of early life environmental factors, including diet, on gut microbiota and neuro-development, emphasizing the potential long-term consequences on health; and also summarize the state of the art regarding the mechanisms underlying diet and gut microbiota influence on the brain-gut axis. Furthermore, we describe the evidence supporting the key role played by gut microbiota, diet and nutrition in neurodevelopment, as well as the effectiveness of certain dietary and microbiome-based interventions aimed at preventing or treating NDDs. Finally, we emphasize the need for further research to gain greater insight into the complex interplay between diet, gut microbiome and brain development. Such knowledge would help towards achieving tailored integrative treatments, including personalized nutrition.

Autism spectrum disorder and air pollution: A systematic review and meta-analysis

Despite the widely-known effects of air pollution, pollutants exposure surrounding pregnancy and the risk for autism spectrum disorder (ASD) in newborns remains controversial. The purpose of our study was to carry out a systematic review and meta-analyses of the risk of ASD in newborns following air pollution exposure during the perinatal period (preconception to second year of life). The PubMed, Cochrane Library, Embase and ScienceDirect databases were searched for articles, published up to July 2020, with the keywords "air pollution" and "autism". Three models were used for each meta-analysis: a global model based on all risks listed in included articles, a pessimistic model based on less favorable data only, and an optimistic model based on the most favorable data only. 28 studies corresponding to a total of 758 997 newborns were included (47190 ASD and 703980 controls). Maternal exposure to all pollutants was associated with an increased risk of ASD in newborns by 3.9% using the global model and by 12.3% using the optimistic model, while the pessimistic model found no change. Each increase of 5 μg/m³ in particulate matter <2.5 μm (PM2.5) was associated with an increased risk of ASD in newborns, regardless of the model used (global +7%, pessimistic +5%, optimistic +15%). This risk increased during preconception (global +17%), during pregnancy (global +5%, and optimistic +16%), and during the postnatal period (global +11% and optimistic +16%). Evidence levels were poor for other pollutants (PM10, NOx, O3, metals, solvents, styrene, PAHs, pesticides). PM2.5 was associated with a greater risk than PM10 (coefficient 0.20, 95CI -0.02 to 0.42), NOx (0.29, 0.08 to 0.50) or solvents (0.24, 0.04 to 0.44). All models revealed that exposure to pollutants, notably PM2.5 during pregnancy, was associated with an increased risk of ASD in newborns. Pregnancy and postnatal periods seem to be the most at-risk periods.

Mitochondria May Mediate Prenatal Environmental Influences in Autism Spectrum Disorder

We propose that the mitochondrion, an essential cellular organelle, mediates the long-term prenatal environmental effects of disease in autism spectrum disorder (ASD). Many prenatal environmental factors which increase the risk of developing ASD influence mitochondria physiology, including toxicant exposures, immune activation, and nutritional factors. Unique types of mitochondrial dysfunction have been associated with ASD and recent studies have linked prenatal environmental exposures to long-term changes in mitochondrial physiology in children with ASD. A better understanding of the role of the mitochondria in the etiology of ASD can lead to targeted therapeutics and strategies to potentially prevent the development of ASD.

A profile and review of findings from the Early Markers for Autism study: unique contributions from a population-based case-control study in California

BACKGROUND

The Early Markers for Autism (EMA) study is a population-based case-control study designed to learn more about early biologic processes involved in ASD.

METHODS

Participants were drawn from Southern California births from 2000 to 2003 with archived prenatal and neonatal screening specimens. Across two phases, children with ASD (n = 629) and intellectual disability without ASD (ID, n = 230) were ascertained from the California Department of Developmental Services (DDS), with diagnoses confirmed according to DSM-IV-TR criteria based on expert clinical review of abstracted records. General population controls (GP, n = 599) were randomly sampled from birth certificate files and matched to ASD cases by sex, birth month and year after excluding individuals with DDS records. EMA has published over 20 papers examining immune markers, endogenous hormones, environmental chemicals, and genetic factors in association with ASD and ID. This review summarizes the results across these studies, as well as the EMA study design and future directions.

RESULTS

EMA enabled several key contributions to the literature, including the examination of biomarker levels in biospecimens prospectively collected during critical windows of neurodevelopment. Key findings from EMA include demonstration of elevated cytokine and chemokine levels in maternal mid-pregnancy serum samples in association with ASD, as well as aberrations in other immune marker levels; suggestions of increased odds of ASD with prenatal exposure to certain endocrine disrupting chemicals, though not in mixture analyses; and demonstration of maternal and fetal genetic influence on prenatal chemical, and maternal and neonatal immune marker and vitamin D levels. We also observed an overall lack of association with ASD and measured maternal and neonatal vitamin D, mercury, and brain-derived neurotrophic factor (BDNF) levels.

LIMITATIONS

Covariate and outcome data were limited to information in Vital Statistics and DDS records. As a study based in Southern California, generalizability for certain environmental exposures may be reduced.

CONCLUSIONS

Results across EMA studies support the importance of the prenatal and neonatal periods in ASD etiology, and provide evidence for the role of the maternal immune response during pregnancy. Future directions for EMA, and the field of ASD in general, include interrogation of mechanistic pathways and examination of combined effects of exposures.