Autism and the Gut Microbiome

April is Autism Awareness month, and while a great deal of scientific evidence in this field remains to be elucidated, an undeniable connection between gut health and Autism Spectrum Disorder (ASD) has already emerged.

Digestive Health and Autism Spectrum Disorders


It is well-known that children with autism experience significantly more GI symptoms than healthy controls. These symptoms can range from diarrhea, constipation, gas, bloating, nausea and vomiting; it’s likely that GI symptoms themselves can be source of behavioral outbusrts for children who struggle to communicate verbally.

But in searching for answers to this complex condition, researchers must seek the root cause, which according to Hippocrates, more than likely begins in the gut.

The intestinal permeability (leaky gut) theory of disease is an important avenue to examine, as the presence of increased intestinal permeability in autistic children is well documented. One study revealed that 36.7% of autistic children in a population presented with leaky gut compared to only 4.8% in the healthy control group (1).

The presentation of leaky gut in these children also improved when they were switched to a gluten and casein free diet. Autistic subjects also show higher levels of bacterial LPS endotoxin that correlates to severity of autistic signs and symptoms and provides strong evidence for the leaky gut connection (2, 34) .

Microbiome exploration holds a great deal of promise for future research. Multiple correlation studies have linked increased or decreased abundance of specific microorganisms with ASD.

Microbiome Diversity


From the broadest perspective, children with ASD show less diverse gut microbial compositions. Novel 16s bacterial testing techniques have revealed some more specific patterns:

  • children on the spectrum tend to carry lower levels of prevotella genus and Akkermansia muciniphila species which may correlate with a thinner intestinal mucus barrier and a compromised ability to produce Vitamin B1 (5).
  • children previously diagnosed with autism have shown increased abundance of clostridium and sutterella species in addition to increased levels of the single microorganism Desulfovibrio piger (6).

These findings suggest that impairments in sulfation and detoxification pathways, compromised bacterial butyrate production, increased inflammation of the intestinal mucosa, and bacterial spore formation may be key variables in autism manifestation (7).

While many more studies are warranted, gut bacterial analysis provides some exciting future direction for autism research, and the Vibrant Wellness GUT PAC can be a very informative tool for any practitioner working with this special, and rapidly expanding population.

So this April, make sure you wear blue to support Autism awareness and remember to keep your gut bugs healthy!

–Cat Simmons, MS RD

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