Nutrition to tackle neurodegeneration? A future possibility, predicts review

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Deeper research into microbiota–gut–brain mechanisms could slow down neurodegeneration and calm anxiety and hyperactivity in children with autism spectrum disorder (ASD), a new paper suggests.

These are the future possibilities envisioned in a review authored by researchers, who describe these future scenarios, made possible by the advent of new advanced models and a greater focus on omics technologies.

The paper, authored by industry and academic researchers, also highlights the need for supporting bioinformatics resources (training, tools) to efficiently translate study findings, as well as the identification of relevant targets in study populations.

“Machine learning technology will become increasingly essential to improving the efficiency and accuracy of study findings,” the review states.

“Indeed, bioinformatics holds the key to integrating large, multi-dimensional datasets and, from that, gaining a better understanding of their clinical significance.

“At the current pace of technological development, it is now possible to imagine the potential of such tools to identify high-risk patients at an early stage, determine which microbial/immunological imbalances may cause such risks and suggest possible interventions to mitigate them.”

Writing in Cellular and Molecular Life Sciences, the research team outline the current situation, in which the microbiota is now firmly the focus of nutritional and therapeutic strategies for improved brain health and well-being.

Key pathways of interest include the vagus nerve that comprises efferent and afferent neurons and is considered the physical connection between brain and gut.

The nerve carries motor signals between the brain and organs, including the intestinal cells, which are also subject to the influence of the gut microbiota. The brain is, in this way, able to ‘sense’ the environment in the gut, the paper adds.

Immune system role

Also playing a core role is the immune system, which has firm roots in the gastrointestinal tract. Evidence of the immune system’s crucial role in ASD, epilepsy, Alzheimer’s disease, Parkinson’s disease and cerebrovascular diseases, is growing with these conditions all having low-grade systemic inflammatory components.

According to the team, this low-grade inflammation is indicative of a malfunctioning immune response and dysbiotic microbiota.

The paper, which includes researchers from Cargill, DSM, IFF Health and Biosciences and Yakult Europe, also go on to discuss the potential for nutritional and therapeutic strategies in addressing some of these conditions.

Here, dietary supplementation with pro-, pre-, syn- and postbiotics, omega-3 polyunsaturated fatty acids and phytochemicals, such as polyphenols, which may act as prebiotics have shown much promise.

Similarly, high-fibre diets—promoting short chain fatty acid (SCFA) production by the gut microbiota—are a promising intervention to overcome maternal-obesity-induced impairment of cognitive and social functions.

Faecal microbiota transplants

The paper also highlights the possibilities of faecal microbiota transplants as another potential therapeutic opportunity, having already been shown to influence hedonic food intake in mice.

The benefits of faecal microbiota transplants can also be applied to cognitive performance and age-related disorders as the review mentions studies in mice that have shown the transplants to correct age-related defects in immune function.

A similar transplant from aged to young mice has a detrimental impact on key functions of the CNS.

These and other findings highlight the importance of the microbiota–gut–brain axis during ageing and raise the possibility that a ‘young’ microbiota may maintain or improve cognitive functions in life’s later years.

Neurological research suggests the microbiota also play a role in neurodegenerative diseases, the researchers state, adding: “This supports the idea that an ageing gut microbiota could be linked to immune and neuronal dysfunction in Parkinson’s and Alzheimer’s disease.

“Indeed, studies of faecal microbiota transplants in transgenic mouse models point to a causal relationship between intestinal microbiota, protein aggregation and cognitive problems. More studies are necessary to confirm this.”

Future goals

The team acknowledge that the prevention of brain disorders may remain out of reach for the foreseeable future, although the mapping of healthy microbiota and communication pathways could enable the early prediction of neurological disorders.

“The first signs of neurodegenerative conditions such as Alzheimer’s and Parkinson’s disease, for example, are known to develop many years before diagnosis. Imagine if it were possible to slow neurodegenerative processes by altering the microbiome,” the paper concludes.

“A similar scenario is imaginable for children with ASD. What if dietary influences on the gut microbiota could both relieve GI irritation and calm anxiety and hyperactivity? And what if it were possible to complement drug and psychiatric therapy for schizophrenia with targeted foods such as probiotics?”

“The time has come to dig even deeper through integrated, multi-disciplinary research—aimed at understanding microbiota–gut–brain mechanisms and identifying true opportunities to adapt and adjust the microbiota for better brain health through life. Continuous investment from the public and private sector is vital to keep up the momentum.”

Source: Cell. Mol. Life Sci

Published online: doi.org/10.1007/s00018-021-04060-w

“The microbiota–gut–brain axis: pathways to better brain health. Perspectives on what we know, what we need to investigate and how to put knowledge into practice.”

Authors: Chakrabarti, A., Geurts, L., Hoyles, L. et al.