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Gut-Brain Health Relation to Autism

Updated: Jun 18, 2022

By Umar Mohammad

March 18, 2022


[Photo credit: ResearchGate]

Hippocrates once stated that ‘all disease begins in the gut’. This isn’t exactly true; it’s relevant to chronic metabolic illnesses, but ‘new’ research says that autism is linked with the gut. How exactly does the gut affect autism? Read on…

Autism is defined as a developmental disorder that is distinguished by the affected person’s hardship in social interaction, as well as repetitive behavior, and general communication (speech/actions).

Autism is categorized into three types. The first is Autistic disorder, the type that the general public thinks of when relating to the word. They generally have the characteristics mentioned above. The second type is Asperger Syndrome and has milder effects. Unlike people with autistic disorder, people with Asperger’s don’t struggle with communication or language. However, they might have idiosyncratic behavioral patterns and may not be able to easily interact socially. The final type in the spectrum is Pervasive Development Disorder - Not Otherwise Specified (PDD-NOS) or else referred to as atypical autism. PDD-NOS has fewer symptoms and lacks severity compared to the first type. The symptoms are only limited to social/communication challenges. Their characteristics are a mix of the symptoms of Autistic disorder and Asperger Syndrome.

There are around 70 million people that fall on the autistic spectrum. Scientists discovered that probiotic therapy reduced the effects of autism-related behaviors. They planned on developing it as a treatment that is mainly limited to behavioral therapy. The gastrointestinal issues have a positive correlation with behavioral symptoms. National Geographic states that around 10% of autistic children don’t have gastrointestinal problems; the rest have gastrointestinal-related problems. Caltech researchers studied mice pups that displayed symptoms of autism and discovered that these mice developed ‘leaky gut’, a digestive condition in which bacteria and toxins are able to “leak” through the intestinal wall. The mice’s blood contained 4EPS, a molecule, but in larger quantities than the average mouse, about 50 times more. The molecule was associated with anxiety; when 4EPS was treated with probiotics, the autistic mice became less anxious and stopped exhibiting symptoms. They did, however, retain their struggle with social interactions.

Harvard University has also affirmed this 'new' theory. The interleukin - 17a is an inflammatory signaling molecule. High levels of the IL -17a molecule affect brain development in the fetus and change the mother's microbiome. This increases the vulnerability of the future child to inflammatory attacks. Higher levels of IL-17a in mice resulted in autism-like symptoms in terms of behavior. They concluded that when the mother had an infection (particularly related to gastroenterology), led to an increase in the chances of developing autism.


“Gut-Brain Connection in Autism.”, 7 Dec. 2021,

Pandika, Melissa. “Autism’s Gut-Brain Connection.” Science, National Geographic, 14 Nov. 2014,

“Autism: Types of Autism Spectrum Disorders.”, 2022,

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