Omega-3 and -6 fatty acid supplementation and sensory processing in toddlers with ASD symptomology born preterm: A randomized controlled trial

Omega-3 fatty acids and health of auditory and vestibular systems: a comprehensive review

PURPOSE

The purpose of this study was to comprehensively review animal and human studies that explore the role of omega-3 PUFAs in maintaining the health of the auditory organ across all life stages.

METHODS

This narrative review involved searching Scopus, PubMed, Google Scholar, and Cochrane Library databases for relevant articles from December 1980 to July 2023.

RESULTS

some animal and human studies suggest that both deficiency and excessive intake of long-chain omega-3 PUFAs, particularly docosahexaenoic acid (DHA), can lead to auditory neural conduction impairment and reduced hearing acuity from fetal development to old age (presbycusis). These effects are likely to be dependent on the dosage. Some research indicates that an excessive intake of omega-3, rather than a deficiency, can result in nutritional toxicity and hearing impairments. Animal studies highlight the positive impact of omega-3 supplements with high DHA content in addressing hearing damage, but human research on this subject is limited. Furthermore, certain studies propose that omega-3 PUFAs may prevent or delay age-related hearing loss, with high plasma omega-3 concentration, particularly long-chain omega-3 PUFA, linked to reduced hearing loss. Additionally, consuming fish more than twice a week may be associated with a lower risk of hearing loss in adulthood, with these effects potentially influenced by age and gender. However, the majority of studies have been conducted on animals, and clinical trials are scarce. Research on the influence of omega-3 PUFAs on the peripheral and central vestibular systems remains limited.

CONCLUSION

This article delves into the impact of omega-3 on the auditory-vestibular system, exploring its influence on neurodevelopment, protection, and treatment. It not only highlights specific research gaps but also offers valuable insights for potential future studies.

A Comparison of the Clinical Presentation of Preterm Birth and Autism Spectrum Disorder: Commonalities and Distinctions in Children Under 3

Premature infants and infants later diagnosed with autism spectrum disorder (ASD) share many commonalities in clinical presentations. However, prematurity and ASD also have differences in clinical presentation. These overlapping phenotypes can lead to misdiagnoses of ASD or missing a diagnosis of ASD in preterm infants. We document these commonalities and differences in various developmental domains with the hope of aiding in the accurate early detection of ASD and timely intervention implementation in children born premature. Given the degree of similarities in presentation, evidence-based interventions designed specifically for preterm toddlers or toddlers with ASD may ultimately aid both populations.

How the placenta-brain lipid axis impacts the nutritional origin of child neurodevelopmental disorders: Focus on attention deficit hyperactivity disorder and autism spectrum disorder

Dietary fish is a rich source of omega-3 (n-3) fatty acids, and as such, is believed to have played an important role in the evolution of the human brain and its advanced cognitive function. The long chain polyunsaturated fatty acids, particularly the n-3 docosahexanoic acid (DHA), are critical for proper neurological development and function. Both low plasma DHA and obesity in pregnancy are associated with neurodevelopmental disorders such as attention deficit and hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) in childhood, and n-3 supplementation has been shown to improve symptoms, as reviewed herein. The mechanisms underlying the connection between maternal obesity, n-3 fatty acid levels and offspring's neurological outcomes are poorly understood, but we review the evidence for a mediating role of the placenta in this relationship. Despite promising data that n-3 fatty acid supplementation mitigates the effect of maternal obesity on placental lipid metabolism, few clinical trials or animal studies have considered the neurological outcomes of offspring of mothers with obesity supplemented with n-3 FA in pregnancy.

Non-specific effect of omega-3 fatty acid supplementation on autistic spectrum disorder: systematic review and meta-analysis

METHODS

We searched seven databases and found 13 eligible controlled trials that use omega-3 supplementation in children and adolescents with ASD.Data extraction: We collected details on study design, intervention time, supplement dosage, and the autism assessment scale. Meta-analyses and subgroup analysis were conducted according to the autism symptoms.

RESULTS

Omega-3 and omega-6 supplementation improved ASD symptoms according to the Aberrant Behavior Checklist (standard mean difference - SMD = -0.13; CI 95% = -0.34, -0.02). However, using subgroup analysis, we observed no efficacy in terms of improvements in hyperactivity (SMD = -0.03; CI 95%: -0.43, 0.36), irritability (SMD = -0.18; CI 95%: -0.51, 0.15), stereotypy (SMD = -0.03; CI 95%: -0.43, 0.36), inappropriate speech (SMD = -0.68; CI 95%: -1.49, 0.14), lethargy (SMD = -0.22; CI 95%: -0.58, 0.14), and social function (SMD = -0.71; IC 95%: -1.56, 0.14). W-3 and w-6 supplementation also showed no efficacy according to the Social Responsiveness Scale (SMD = 0.08; CI 95%: -0.23, 0.39). The adverse effects were classified as mild and equally distributed between the placebo and intervention groups.

CONCLUSIONS

Despite w-3 and w-6 supplementation showing minimal beneficial effects in the treatment of autism, the subgroup analyses indicated that there is a lack of evidence on the beneficial role of w-3 and w-6 in treating ASD.Systematic Review Registration: PROSPERO number CRD42020146116.

Perinatal Dietary Polyunsaturated Fatty Acids in Brain Development, Role in Neurodevelopmental Disorders

n-3 and n-6 polyunsaturated fatty acids (PUFAs) are essential fatty acids that are provided by dietary intake. Growing evidence suggests that n-3 and n-6 PUFAs are paramount for brain functions. They constitute crucial elements of cellular membranes, especially in the brain. They are the precursors of several metabolites with different effects on inflammation and neuron outgrowth. Overall, long-chain PUFAs accumulate in the offspring brain during the embryonic and post-natal periods. In this review, we discuss how they accumulate in the developing brain, considering the maternal dietary supply, the polymorphisms of genes involved in their metabolism, and the differences linked to gender. We also report the mechanisms linking their bioavailability in the developing brain, their transfer from the mother to the embryo through the placenta, and their role in brain development. In addition, data on the potential role of altered bioavailability of long-chain n-3 PUFAs in the etiologies of neurodevelopmental diseases, such as autism, attention deficit and hyperactivity disorder, and schizophrenia, are reviewed.

The Role of Lipidomics in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a complex neurodevelopmental syndrome commonly diagnosed in early childhood; it is usually characterized by impairment in reciprocal communication and speech, repetitive behaviors, and social withdrawal with loss in communication skills. Its development may be affected by a variety of environmental and genetic factors. Trained physicians diagnose and evaluate the severity of ASD based on clinical evaluations of observed behaviors. As such, this approach is inevitably dependent on the expertise and subjective assessment of those administering the clinical evaluations. There is a need to identify objective biological markers associated with diagnosis or clinical severity of the disorder. Several important issues and concerns exist regarding the diagnostic competence of the many abnormal plasma metabolites produced in the different biochemical pathways evaluated in individuals with ASD. The search for high-performing bio-analytes to diagnose and follow-up ASD development is still a major target in medicine. Dysregulation in the oxidative stress response and proinflammatory processes are major etiological causes of ASD pathogenesis. Furthermore, dicarboxylic acid metabolites, cholesterol-related metabolites, phospholipid-related metabolites, and lipid transporters and mediators are impaired in different pathological conditions that have a role in the ASD etiology. A mechanism may exist by which pro-oxidant environmental stressors and abnormal metabolites regulate clinical manifestations and development of ASD.

Relationship between the effect of polyunsaturated fatty acids (PUFAs) on brain plasticity and the improvement on cognition and behavior in individuals with autism spectrum disorder

Objective: This work aimed to compile information about the neuronal processes in which polyunsaturated fatty acids (PUFAs) could modulate brain plasticity, in order to analyze the role of nutritional intervention with the ω-3 and ω-6 fatty acids as a therapeutic strategy for the Autism Spectrum Disorder (ASD)-related signs and symptoms.Methods: We reviewed different articles reporting the effect of PUFAS on neurite elongation, membrane expansion, cytoskeleton rearrangement and neurotransmission, considering the ASD-related abnormalities in these processes.Results: In accordance to the reviewed studies, it is clear that ASD is one of the neurological conditions associated with an impairment in neuronal plasticity; therefore, PUFAs-rich diet improvements on cognition and behavioral deficits in individuals with autism, could be involved with the regulation of neuronal processes implicated in the atypical brain plasticity related with this neurodevelopmental disorder.Discussion: The behavioral and cognitive improvement observed in individuals with ASD after PUFAs treatment might underlie, at least in part, in the ability of ω-3 and ω-6 fatty acids to induce neurite outgrowth, probably, through the dynamic regulation of the neuronal cytoskeleton along with the expansion of neuronal membranes. Furthermore, it might also be associated with an enhancement of the efficacy of synaptic transmission and the modulation of neurotransmitters release.

Impact of polyunsaturated fatty acids on patient-important outcomes in children and adolescents with autism spectrum disorder: a systematic review

BACKGROUND

Recent randomized controlled trials (RCTs) claimed PUFAs to be effective for autism spectrum disorder (ASD) but international guidelines have not considered yet this body of evidence. Our aim was to assess the effectiveness of PUFAs in children and adolescents with ASD, for the Italian national guidelines on the management of ASD in children and adolescents.

METHODS

We performed a systematic review and meta-analysis of RCTs comparing PUFAs versus placebo or a healthy diet for the treatment of ASD in children and adolescents. The outcomes considered were deemed by the guideline panel to be highly relevant to children and adolescents with ASD and to their caregivers. The outcomes included hyperactivity, quality of sleep, self-harm, aggression, irritability, anxiety, attention, adaptive functioning, social interaction, restricted and repetitive interests and behavior, communication, hyperactivity and disruptive behaviors coexistent with core symptoms. The risk of bias of the included studies was assessed with the Cochrane tool, and the rating of the confidence in the effect estimates according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

RESULTS

We included 9 studies with 405 participants. The strength of evidence ranged from low to very low. Six studies included preschoolers and school-age children, three studies included both children and adolescents. The majority of participants were males (83.8%), with a mean age of 6.7 years. PUFAs were superior compared to placebo in reducing anxiety in individuals with ASD (SMD -1.01, 95% CI - 1.86 to - 0.17; very low certainty of evidence). Moreover, PUFAs worsened quality of sleep compared to a healthy diet (SMD 1.11, 95% CI 0.21 to 2.00; very low certainty of evidence). PUFAs were not better than placebo in reducing aggression, hyperactivity, adaptive functioning, irritability, restricted and repetitive interests and behaviors and communication. Effects on some critical outcomes such as sleep, self-harm and disruptive behavior are currently unknown. The main limitations were the small number of participants included in the RCTs and the dosage which varied greatly (from 200 mg/day to 1540 mg/day), making it difficult to address causal inference.

CONCLUSIONS

PUFAs did not show evidence of effect in children and adolescents with ASD and the certainty of evidence as measured with the GRADE was low to very low. Further research is needed on this topic because the available evidence is inconclusive.

Systematic review of sensory processing in preterm children reveals abnormal sensory modulation, somatosensory processing and sensory-based motor processing

AIM

Preterm birth poses concerns in daily functioning and behaviour in childhood, possibly connected to sensory processing disorder. This review aimed to systematically identify assessments, incidence and nature of sensory processing disorder in preterm-born infants and children.

METHODS

We searched literature through CINAHL-EBSCOhost, Cochrane, Ovid/PsychINFO, PubMed/Medline, Scopus and Google Scholar, published until November 2018. We included electronically available, peer-reviewed studies of preterm-born children that applied standardised sensory processing assessments. We excluded studies of preterm-born children with major neurodevelopmental impairments.

RESULTS

We identified 27 studies of premature children, aged from birth to 9 years 7 months. The assessments represented three versions of Sensory Profile questionnaires and three clinical tests, Test of Sensory Functions in Infants, the Miller Assessment for Preschoolers, and the Sensory Integration and Praxis Test. The studies revealed wide variation of atypical sensory processing: 28%-87% in sensory modulation, 9%-70% in somatosensory processing and 20%-70% in sensory-based motor processing.

CONCLUSION

Preterm-born children exhibited elevated risk for sensory processing disorder from infancy into school age. Routine screening of sensory processing, intervention intervals and parental consultations should be considered in ameliorating sensory processing and neurocognitive development. Moreover, a larger body of intervention studies is needed.

Dietary Approaches to the Management of Autism Spectrum Disorders

This chapter reviews the literature surrounding autism spectrum disorders (ASD) and their relation to gastrointestinal (GI), behavioral, neurological, and immunological functioning. Individuals with ASD often have poor GI health, including bowel motility issues, autoimmune and/or other adverse responses to certain foods, and lack of necessary nutrient absorption. These issues may be caused or exacerbated by restrictive behavioral patterns (e.g., preference for sweet and salty foods and/or refusal of healthy foods). Those individuals with GI issues tend to demonstrate more behavioral deficits (e.g., irritability, agitation, hyperactivity) and also tend to have an imbalance in overall gut microbiome composition, thus corroborating several studies that have implicated brain-gut pathways as potential mediators of behavioral dysfunction.We examine the literature regarding dietary approaches to managing ASDs, including elimination diets for gluten, casein, or complex carbohydrates, a ketogenic diet, and a low oxalate diet. We also explore the research examining dietary supplements such as fatty acids, pro- and prebiotics, vitamins, minerals, glutathione, phytochemicals, and hormones. The research on dietary approaches to managing ASDs is limited and the results are mixed. However, a few approaches, such as the gluten-free/casein-free diet, fatty acid supplementation, and pre/probiotics have generally demonstrated improved GI and associated behavioral symptoms. Given that GI issues seem to be overrepresented in ASD populations, and that GI issues have been associated with a number behavioral and neurological deficits, dietary manipulation may offer a cheap and easily implemented approach to improve the lives of those with ASD.

Nutritional interventions for autism spectrum disorder

Autism spectrum disorder (ASD) is an increasingly prevalent neurodevelopmental disorder with considerable clinical heterogeneity. With no cure for the disorder, treatments commonly center around speech and behavioral therapies to improve the characteristic social, behavioral, and communicative symptoms of ASD. Gastrointestinal disturbances are commonly encountered comorbidities that are thought to be not only another symptom of ASD but to also play an active role in modulating the expression of social and behavioral symptoms. Therefore, nutritional interventions are used by a majority of those with ASD both with and without clinical supervision to alleviate gastrointestinal and behavioral symptoms. Despite a considerable interest in dietary interventions, no consensus exists regarding optimal nutritional therapy. Thus, patients and physicians are left to choose from a myriad of dietary protocols. This review, summarizes the state of the current clinical and experimental literature on nutritional interventions for ASD, including gluten-free and casein-free, ketogenic, and specific carbohydrate diets, as well as probiotics, polyunsaturated fatty acids, and dietary supplements (vitamins A, C, B6, and B12; magnesium and folate).

Investigational drugs in early-stage clinical trials for autism spectrum disorder

Introduction: Pharmacologic interventions in Autism Spectrum Disorder (ASD) have historically focused on symptom-based approaches. However, a treatment for the core social deficits has remained unidentified. While a definitive theory for the cause of ASD is not yet known, recent advances in our understanding of ASD pathophysiology have opened the door for research on new pharmaceutical methods to target core symptomology. Areas covered: Herein, we review the novel pharmacologic therapies undergoing early-stage clinical trials for the treatment of the social symptoms associated with ASD. Specifically, these strategies center on altering neurologic excitatory and inhibitory imbalance, neuropeptide abnormalities, immunologic dysfunction, and biochemical deficiencies in ASD. Expert opinion: Utilizing the growing field of knowledge regarding the pathological mechanisms and altered neurobiology of individuals with ASD has led to the development of many innovative pharmaceutical interventions. Clinical trials for neurobiologic and immunologic targets show promise in impacting the social behavior and processing deficits in ASD but need evaluation in larger clinical trials and continued biomarker development to more effectively and consistently assess pharmacologic effects. Additionally, evaluating patient-specific drug responsivity and integrating behavioral intervention in conjunction with pharmacologic treatment is crucial to developing a successful approach to ASD treatment.

A Randomised-Controlled Trial of Vitamin D and Omega-3 Long Chain Polyunsaturated Fatty Acids in the Treatment of Core Symptoms of Autism Spectrum Disorder in Children

We evaluated the efficacy of vitamin D (VID), omega-3 long chain polyunsaturated fatty acids (omega-3 LCPUFA, OM), or both (VIDOM) on core symptoms of ASD. New Zealand children with ASD (n = 73; aged 2.5-8.0 years) received daily 2000 IU vitamin D₃, 722 mg docosahexaenoic acid, both, or placebo. Outcome measures were Social Responsiveness Scale (SRS) and Sensory Processing Measure (SPM). Of 42 outcome measures comparisons (interventions vs. placebo), two showed greater improvements (P = 0.03, OM and VIDOM for SRS-social awareness) and four showed trends for greater improvements (P < 0.1, VIDOM for SRS-social communicative functioning, OM for SRS-total, VIDOM for SPM-taste/smell and OM for SPM-balance/motion). Omega-3 LCPUFA with and without vitamin D may improve some core symptoms of ASD but no definitive conclusions can be made.

Repurposing available drugs for neurodevelopmental disorders: The fragile X experience

Many available drugs have been repurposed as treatments for neurodevelopmental disorders. In the specific case of fragile X syndrome, many clinical trials of available drugs have been conducted with the goal of disease modification. In some cases, detailed understanding of basic disease mechanisms has guided the choice of drugs for clinical trials, and several notable successes in fragile X clinical trials have led to common use of drugs such as minocycline in routine medical practice. Newer technologies like Disease-Gene Expression Matching (DGEM) may allow for more rapid identification of promising repurposing candidates. A DGEM study predicted that sulindac could be therapeutic for fragile X, and subsequent preclinical validation studies have shown promising results. The use of combinations of available drugs and nutraceuticals has the potential to greatly expand the options for repurposing, and may even be a viable business strategy. This article is part of the Special Issue entitled 'Drug Repurposing: old molecules, new ways to fast track drug discovery and development for CNS disorders'.