1.
Towards Tailored Gut Microbiome-Based and Dietary Interventions for Promoting the Development and Maintenance of a Healthy Brain.
Larroya, A, Pantoja, J, Codoñer-Franch, P, Cenit, MC
Frontiers in pediatrics. 2021;9:705859
-
-
-
Free full text
Plain language summary
The cause of neurodevelopmental disorders (NDDs) is complex and multifactorial. Recent studies have indicated that early life disturbances of the gut microbiome can impact neurodevelopment, suggesting this critical window may play a key role in the prevention or progression of neurological disease. The growing field of personalized nutrition works on the basis of tailored dietary intervention strategies that consider individual variability based on genetics, diet, and the environment. The aim of this paper is to review the current evidence on the neurodevelopmental interaction between the gut microbiota, environment and host, and assess the efficacy of tailored, personalized nutrition interventions aimed at preventing or treating NDDs. The literature provides evidence that the gut microbiota is susceptible to influence by various factors early in life, and the health of the microbiome may modulate mental health consequences later in life. Additionally, key nutritional deficiencies and microbiome alterations have been linked to NDDs, suggesting potential markers that may lead to improved prevention and treatment. Based on the current literature, the authors emphasize the need for further research during the critical window of microbiome development in order to target the cause of neurodevelopmental impairments. They suggest these findings could help progress the field of Nutritional Psychiatry towards effective tailored nutrition and personalized medicine.
Abstract
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.
2.
The role of the microbiota-gut-brain axis in neuropsychiatric disorders.
Generoso, JS, Giridharan, VV, Lee, J, Macedo, D, Barichello, T
Revista brasileira de psiquiatria (Sao Paulo, Brazil : 1999). 2021;43(3):293-305
-
-
-
Free full text
Plain language summary
Metabolites produced by the gut microbiota have been shown to influence mood and behaviour via the microbiota-gut-brain axis, and there is increased interest in better understanding this interaction in the context of mental health. This review summarises the evidence around the influence of gut microbiota in various neuropsychiatric disorders, primarily focusing on the metabolic pathways that originate in the gut microbiota. Current research highlights an association between gut microbiota metabolites with neuropsychiatric disorders and that probiotics demonstrate a significant therapeutic role in many of these disorders. Based on the current literature, the authors conclude it is crucial to better understand the complex microbiota-host interaction in health and disease, leading to more targeted and improved therapeutic interventions.
Abstract
The microbiota-gut-brain axis is a bidirectional signaling mechanism between the gastrointestinal tract and the central nervous system. The complexity of the intestinal ecosystem is extraordinary; it comprises more than 100 trillion microbial cells that inhabit the small and large intestine, and this interaction between microbiota and intestinal epithelium can cause physiological changes in the brain and influence mood and behavior. Currently, there has been an emphasis on how such interactions affect mental health. Evidence indicates that intestinal microbiota are involved in neurological and psychiatric disorders. This review covers evidence for the influence of gut microbiota on the brain and behavior in Alzheimer disease, dementia, anxiety, autism spectrum disorder, bipolar disorder, major depressive disorder, Parkinson's disease, and schizophrenia. The primary focus is on the pathways involved in intestinal metabolites of microbial origin, including short-chain fatty acids, tryptophan metabolites, and bacterial components that can activate the host's immune system. We also list clinical evidence regarding prebiotics, probiotics, and fecal microbiota transplantation as adjuvant therapies for neuropsychiatric disorders.
3.
Relationship between Autism Spectrum Disorder and Pesticides: A Systematic Review of Human and Preclinical Models.
Biosca-Brull, J, Pérez-Fernández, C, Mora, S, Carrillo, B, Pinos, H, Conejo, NM, Collado, P, Arias, JL, Martín-Sánchez, F, Sánchez-Santed, F, et al
International journal of environmental research and public health. 2021;18(10)
-
-
-
Free full text
Plain language summary
Autism spectrum disorder (ASD) is characterized by neurodevelopmental differences in the brain that manifest in divergent social and communicative abilities and stereotyped behaviours. The prevalence of ASD diagnoses has risen sharply in recent years, possibly due to changes in diagnostics criteria, but this does not fully explain the increase. ASD has known genetic predispositions, but vulnerability factors, such as influences from the external environment, are thought to influence the development of the condition. Exposure to pesticides has been of interest here, as both human and rodent studies have demonstrated links between certain pesticides and ASD-like behaviours and diagnosis. This systematic review sought to summarize current knowledge from preclinical and epidemiological studies. It included 45 human and 16 preclinical studies from animal models, focusing on Organophosphates, Organochlorine, Pyrethroid, Neonicotinoid, Carbamate, and exposure to mixed pesticides. The anayisis yielded no clear conclusion as the complexity of influencing factors made the studies hard to summarize. I.e. different types of pesticides, exposure duration, exposure routes and methodologies used in the various studies. Another problem highlighted by the author is that it is impossible to look at pesticide exposure in isolation as it always co-exists with other factors that may be harmful or beneficial for the development of the nervous system. Such as lifestyle, socioeconomics, educational status, ethnicity, gender or genetics. However, evidence suggests that some compounds like Organophosphates, Organochlorine and Pyrethroid appear to have an impact on cognitive and behavioural functions in children following exposure. Yet, further clinical research is needed to draw firm conclusions on pesticide exposures in humans and ASD in general. Overall this review yields a comprehensive overview of various pesticides and their evidence on ASD. Whilst awaiting further research more solid conclusions may be drawn by focusing on specific compounds and their existing research
Abstract
Autism spectrum disorder (ASD) is a complex set of neurodevelopmental pathologies characterized by impoverished social and communicative abilities and stereotyped behaviors. Although its genetic basis is unquestionable, the involvement of environmental factors such as exposure to pesticides has also been proposed. Despite the systematic analyses of this relationship in humans, there are no specific reviews including both human and preclinical models. The present systematic review summarizes, analyzes, and discusses recent advances in preclinical and epidemiological studies. We included 45 human and 16 preclinical studies. These studies focused on Organophosphates (OP), Organochlorine (OC), Pyrethroid (PT), Neonicotinoid (NN), Carbamate (CM), and mixed exposures. Preclinical studies, where the OP Chlorpyrifos (CPF) compound is the one most studied, pointed to an association between gestational exposure and increased ASD-like behaviors, although the data are inconclusive with regard to other ages or pesticides. Studies in humans focused on prenatal exposure to OP and OC agents, and report cognitive and behavioral alterations related to ASD symptomatology. The results of both suggest that gestational exposure to certain OP agents could be linked to the clinical signs of ASD. Future experimental studies should focus on extending the analysis of ASD-like behaviors in preclinical models and include exposure patterns similar to those observed in human studies.
4.
Dietary Considerations in Autism Spectrum Disorders: The Potential Role of Protein Digestion and Microbial Putrefaction in the Gut-Brain Axis.
Sanctuary, MR, Kain, JN, Angkustsiri, K, German, JB
Frontiers in nutrition. 2018;5:40
-
-
-
Free full text
Plain language summary
Children with autism spectrum disorder (ASD) display high incidence of gastrointestinal (GI) co-morbidities. Growing evidence now shows an association between diet and ASD, demonstrating that impaired gut function may worsen both GI and behavioural symptoms associated with ASD. The aim of this review was to examine the existing literature to further understand the connection between gut structure and function and ASD. This review found children with ASD and gut co-morbidities exhibit poor protein digestion, impaired gut-barrier integrity and a compromised gut microbiome. A potential mechanistic explanation is that the elevated level of undigested proteins is negatively affecting the integrity of the gut. Based on these findings, the authors conclude it is urgent to perform more experimental and clinical research on the “fragile gut” in children with ASD in order to move towards advancements in individualised clinical practice.
Abstract
Children with autism spectrum disorders (ASD), characterized by a range of behavioral abnormalities and social deficits, display high incidence of gastrointestinal (GI) co-morbidities including chronic constipation and diarrhea. Research is now increasingly able to characterize the "fragile gut" in these children and understand the role that impairment of specific GI functions plays in the GI symptoms associated with ASD. This mechanistic understanding is extending to the interactions between diet and ASD, including food structure and protein digestive capacity in exacerbating autistic symptoms. Children with ASD and gut co-morbidities exhibit low digestive enzyme activity, impaired gut barrier integrity and the presence of antibodies specific for dietary proteins in the peripheral circulation. These findings support the hypothesis that entry of dietary peptides from the gut lumen into the vasculature are associated with an aberrant immune response. Furthermore, a subset of children with ASD exhibit high concentrations of metabolites originating from microbial activity on proteinaceous substrates. Taken together, the combination of specific protein intakes poor digestion, gut barrier integrity, microbiota composition and function all on a background of ASD represents a phenotypic pattern. A potential consequence of this pattern of conditions is that the fragile gut of some children with ASD is at risk for GI symptoms that may be amenable to improvement with specific dietary changes. There is growing evidence that shows an association between gut dysfunction and dysbiosis and ASD symptoms. It is therefore urgent to perform more experimental and clinical research on the "fragile gut" in children with ASD in order to move toward advancements in clinical practice. Identifying those factors that are of clinical value will provide an evidence-based path to individual management and targeted solutions; from real time sensing to the design of diets with personalized protein source/processing, all to improve GI function in children with ASD.