Children diagnosed with autism spectrum disorder (ASD) frequently experience abdominal pain, constipation, vomiting, and diarrhea. In recent years, growing evidence suggests that autism spectrum disorder (ASD) is closely associated with gastrointestinal health. Research indicates that the bacterial populations of the gut microbiome can influence gastrointestinal and neurobehavioral ASD symptoms.
Although there is no cure for ASD, various medications, diets, supplements, and therapies can help manage its symptoms. Owing to the strong connection between the gut microbiome and ASD, interventions aimed at normalizing the gut microbiome might help manage ASD symptoms.
This post explains how autism is linked to gut bacteria, how a mother’s gut bacteria can affect a child’s risk of ASD, and why one should consider butyric acid supplementation to help manage ASD symptoms. Use the links below to jump ahead to different topics on the page.
Gut-Brain Connection in Autism Spectrum Disorder
The gut contains millions of nerve cells that form an extensive network called the enteric nervous system (ENS), also known as the ‘second brain.’ The ENS and the central nervous system (CNS), mainly connected through the vagus nerve, form the gut-brain axis.
The bi-directional communication between our gut and brain through the ENS, CNS, hormones, neurotransmitters, and immune responses greatly influences neurological and gastrointestinal health. For example, as much as 90 percent of neurotransmitters, such as serotonin, are produced in the gut and influence our emotions by regulating the gut-brain axis.
The human gut microbiome consists of trillions of bacterial cells primarily involved in beneficial activities such as producing metabolites, transporting them, and maintaining gut homeostasis. However, various pathogenic microbes, like Clostridium bolteae, can adversely affect the gut, resulting in unwanted gastrointestinal conditions. Interestingly, Clostridium bacteria in the colon is associated with a higher risk and severity of ASD, potentially due to mechanisms involving gut-brain interactions and neurotoxic metabolite production.1
How Autism Is Linked to Gut Bacteria
Several pilot studies on the gastrointestinal bacterial composition in ASD reveal that the gut microbiota composition is distinctive in ASD children. A high acidic pH level in their stools indicates an imbalance in the microbiota that can lead to downstream adverse effects on the gastrointestinal and nervous systems through the gut-brain axis.
The following table highlights several studies indicating how autism is linked to gut bacteria.
|
Links Between Autism and Gut Bacteria |
|---|
|
|
These studies indicate how the presence of pathogenic and less diverse gut microbial composition might elicit adverse neurobehavioral symptoms via the gut-brain connection.
In addition, ASD symptoms are associated with higher levels of intestinal permeability and defects in the gastrointestinal barrier.4 A higher level of intestinal permeability can result in toxins and the by-products produced by pathogenic bacteria traveling through the gut-brain axis, which can then disrupt chemical balances in the brain and exacerbate ASD symptoms.
How Short-Chain Fatty Acids Alter Gut Microbiome
Multiple short-chain fatty acids (SCFAs) in the large intestine are produced from the fermentation of carbohydrates, such as dietary fibers, by the gut’s microbiota. SCFAs can cross the blood-brain barrier and affect CNS functions, such as regulating oxidative stress and neuronal cell death, and maintaining normal inflammatory responses in nerve cells. The primary short-chain fatty acids (SCFAs) in the large intestine are:
- Acetic acid
- Propionic acid
- Butyric acid
Studies show altered gut compositions in children with ASD, characterized by elevated levels of SCFAs, particularly propionic acid. Excess propionic acid that crosses the blood-brain barrier sets the stage for a toxic environment that can result in cognitive and motor impairments. It has been observed that the greater the gastrointestinal disturbance in autistic children, the greater the risk of behavioral problems, language impairment, and irritability.
Although the exact mechanism of SCFAs’ influence on the CNS is still unclear, research indicates that SCFAs do modify neurological processes at the molecular level and thus have the potential to affect behavior.
Evidence for the role of SCFAs in influencing CNS functions highlights their role in influencing the gut-brain axis and their fluctuating levels.
Does a Mother’s Gut Bacteria Affect A Child’s Risk for Autism?
Animal studies indicate that variations in maternal gut microbiota might increase the risk of ASD in children. The maternal gut microbiota is associated with neurodevelopmental abnormalities in mouse offspring. Further studies highlight a strong genetic influence on the development of autism.
In a pilot study examining the relationship between the gut microbiome profiles of children with ASD and their mothers, researchers observed a striking correlation between the microbiomes of the mother-child pairs.5 However, because the mothers of children with ASD were neurotypical, they presented variations in their bacterial biomarkers. Compared to their mothers, children with ASD harbor unique bacterial biomarkers, such as increased amounts of the pathogenic genera Alcaligenaceae, Clostridium, Haemophilus, and Wautersiella.
Interestingly, emerging studies have also indicated that both genetic and epigenetic factors in paternal sperm also play a significant role in the development of ASD in children.
Nutritional Supplements that Promote Gut Health and Help Manage ASD Symptoms
Both preliminary research and anecdotal evidence indicate that probiotics, prebiotics, and dietary changes can be effective in addressing the symptoms of autism. The following table highlights several key dietary nutrients that can beneficially address ASD symptoms.
|
Key Dietary Nutrients for Managing the Symptoms of Autism |
|---|
|
|
|
|
|
|
Butyric Acid Supplementation for ASD-Affected Children
The link between autism, gut bacteria, and gut health is well-established. As a key energy substrate for colon cells, butyric acid enhances mitochondrial function in cell lines in male children with autism.6
For all children with ASD, butyric acid supplementation can enhance gut health by up-regulating the beneficial activity of the white blood cells in the colon, thereby generating a more normal inflammatory response. Butyric acid might also serve as a critical metabolite to help rescue energy metabolism in ASD-affected individuals.
AuRx® is a stabilized butyric acid complex developed by Tesseract Medical Research to provide specific nutritional support for children with ASD. This hypoallergenic formulation, delivered in a palatable-tasting powder, enables the maximum absorption and bioavailability of butyric acid molecules through the proprietary CyLoc® – DexKey® nutrient delivery nanotechnology. Tesseract’s gold-standard medical food is intended to counter the gut-brain nutrient imbalance experienced by children with ASD.
The power of Tesseract supplements lies in enhancing palatability, maximizing solubility, absorption and bioavailability, and micro-dosing multiple nutrients in a single, highly effective capsule. Shop products on our website and learn more about how they support your neurological health.*
References
1Rosenfeld CS. Microbiome disturbances and Autism Spectrum Disorders.” Drug Metabolism and Disposition: The Biological Fate of Chemicals vol. 43,10 (2015):1557-1571. doi:10.1124/dmd.115.063826
2Abuljadayel D, et al. Gut microbiota of children with autism spectrum disorder and healthy siblings: A comparative study. Experimental and Therapeutic Medicine vol. 28,5 430. 16 Sep. 2024, doi:10.3892/etm.2024.12719
3Kang D-W, et al. Reduced incidence of Prevotella and other fermenters in intestinal microflora of autistic children. PloS One vol. 8,7 e68322. 3 Jul. 2013, doi:10.1371/journal.pone.0068322
4Li Q, et al. The gut microbiota and Autism Spectrum Disorders.” Frontiers in Cellular Neuroscience vol. 11 120. 28 Apr. 2017, doi:10.3389/fncel.2017.00120
5Li N, et al. Correlation of gut microbiome between ASD children and mothers and potential biomarkers for risk assessment.” Genomics, Proteomics & Bioinformatics vol. 17,1 (2019):26-38. doi:10.1016/j.gpb.2019.01.002
6Rose S, et al. Butyrate enhances mitochondrial function during oxidative stress in cell lines from boys with autism. Translational Psychiatry vol. 8,1 42. 2 Feb. 2018, doi:10.1038/s41398-017-0089-z
