An imbalance of gut metabolites in children with autism disrupts neurotransmitter production, influencing behavioral symptoms (Apr 2025, n=84) Relationships between brain activity, tryptophan-related gut metabolites, and autism symptomatology Other

[Michael Harrop]

https://www.eurekalert.org/news-releases/1080059
https://www.nature.com/articles/s41467-025-58459-1

“We demonstrated that gut metabolites impact the brain, and the brain, in turn, affects behavior. Essentially, the brain acts as the intermediary between gut health and autism-related behaviors,”. “Previous studies highlighted differences in gut microbiomes and brain structures in autism, but our research connects the dots.”

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most of the neurons from the gut send signals to the brain; there are actually more neurons in the gut than in the spinal cord. About 90% of the neural signals between the gut and brain travel from the gut to the brain, while only 10% go in the opposite direction.

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Abstract​

While it has been suggested that alterations in the composition of gut microbial metabolites may play a causative role in the pathophysiology of autism spectrum disorder (ASD), it is not known how gut microbial metabolites are associated with ASD-specific brain alterations.

In this cross-sectional, case-control observational study, (i) fecal metabolomics, (ii) task-based functional magnetic resonance imaging (fMRI), and (iii) behavioral assessments were obtained from 43 ASD and 41 neurotypical (NT) children, aged 8–17. The fMRI tasks used socio-emotional and sensory paradigms that commonly reveal strong evoked brain differences in ASD participants.

Our results show that fecal levels of specific tryptophan-related metabolites, including kynurenate, were significantly lower in ASD compared to NT, and were associated with: 1) alterations in insular and cingulate cortical activity previously implicated in ASD; and 2) ASD severity and symptoms (e.g., ADOS scores, disgust propensity, and sensory sensitivities). Moreover, activity in the mid-insula and mid-cingulate significantly mediated relationships between the microbial tryptophan metabolites (indolelactate and tryptophan betaine) and ASD severity and disgust sensitivity.

Thus, we identify associations between gut microbial tryptophan metabolites, ASD symptoms, and brain activity in humans, particularly in brain regions associated with interoceptive processing.

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[Otto Kretschmer]

Another autism study, nice!

I would like to do some personality and cognitive optimization of myself and I am frustrated how slow the pace of development is. The standard of care for Neuroticism are the SSRIs which were introduced in 1987, the same year Amiga 500 was released. Can you imagine Amiga 500 being the best computer available for 40 years?