Updated on April 7, 2023
Autism spectrum disorder drastically shapes the lives of patients and caregivers, often presenting challenges that greatly compromise quality of life. Despite years of research, there are presently no curative therapies nor combination of therapies that can address the root causes of the disorder. However, there might be new hope for autistic individuals. Although autism has historically been considered a predominantly behavioral disorder, more recent perspectives are incorporating gastrointestinal dysfunction and metabolic aberrations into the disorder’s pathology.
As a result of this new understanding, gastrointestinal symptoms, like diarrhea and constipation, are joining behavioral features, like social withdrawal and repetitive behaviors, as primary symptoms that signify the disorder. However, some researchers are going one step further: they believe that gut dysfunction might play a causative role in several of autism’s behavioral symptoms. In light of this hypothesis, new therapeutic strategies are being designed around the idea that it might be possible to address autism symptoms by rectifying an autistic individual’s GI difficulties. A growing number of researchers are now suggesting that butyric acid supplementation is a particularly promising therapeutic option, potentially opening the door to improved quality of life.
Gastrointestinal difficulties and poor gut health are a common complaint among autistic individuals. According to a 2003 study of 137 autistic children, 24 percent experienced chronic gastrointestinal problems, most commonly diarrhea and constipation. Chronic diarrhea was reported by 17 percent, suggesting that autistic children experience excessive gut motility or an inability to successfully absorb liquid from their food. Constipation, on the other hand, would signal a deficit of gut motility. These conflicting symptoms might occur at different times in the same patient, making identification of disease pathology difficult. No matter the cause, inconsistency in the data is common owing to autism’s multifactorial complexity.
Other research suggests the number of individuals with GI issues and autism is likely greater than 24 percent. A 2002 study found that 41 percent of autistic children chronically experienced an average of four or more gastrointestinal symptoms without an identifiable cause—36 percent more than healthy controls. In contrast to the 2003 study, the 2002 study found that generalized abdominal discomfort was the most common symptom. The consequences of these gastrointestinal symptoms were often behavioral symptoms, such as irritability or unexplained crying, both of which chronically co-occurred in more than 40 percent of the children with GI symptoms.
But the prevalence and severity of gastrointestinal symptoms are only one part of the story; the intestines of autistic individuals are dysfunctional in ways that patients might not directly perceive. Significantly, the 2002 study found that 23 percent of autistic children experienced rapid cycling between diarrhea and constipation from day to day. This would suggest there is more than one pathology implicated in the gut symptoms associated with autism. To understand what one of these pathologies might be, researchers are now examining the gut microbiome.
The gut microbiome is a critical factor in determining a potential connection between autism and gut health. A growing body of research shows the gut microbiomes of autistic individuals are markedly different from those of healthy people. Under normal circumstances, the gut microbiome is populated by hundreds of different species of beneficial bacteria. These bacteria are responsible for facilitating digestion and, by virtue of occupying the habitable areas of the gut, preventing other bacteria that might be harmful from becoming established. On the other hand, a disproportionate representation of healthy bacteria might still be detrimental.
Another 2002 study found that of the bacteria species most common to the microbiome, autistic individuals had far greater numbers of each species than healthy individuals. Using stool samples, researchers found that autistic individuals had roughly 2.1 million bacteria for each of the common microbiome species in their stools, whereas, individuals without autism had only 160,000 specimens of each bacterial species in their stools. Additionally, autistic individuals had a proportionally larger population of bacteria within the Clostridia genus than healthy individuals.
The same study also found that autistic individuals had strains of bacteria in their microbiome that are not found in the microbiome of healthy individuals. 80 percent of autistic individuals had non-spore-forming anaerobic and microaerophilic bacteria, whereas zero percent of the healthy controls had similar colonies of these types. For 50 percent of the autistic study participants who experienced the divergent bacteria, there were upwards of seven different species of microbiota that were not found in the healthy controls. The remaining subjects had fewer variant species. These discoveries provide compelling evidence that autistic individuals have difficulty a normally healthy microbiome.
Microbiome irregularities can easily throw the entire GI system out of working order. Fifty percent of the autistic individuals had a highly acidic pH level in their stools, although the degree of acidity beyond normal ranges varied significantly from individual to individual. This acidity was likely the result of the stools being heavily laden with microbiota. An acidic pH within the gut itself could cause any number of adverse symptoms, including bloating and gas, and it’s likely that the magnitude of deviation dictates the magnitude of the symptoms experienced by the individual.
One fecal sample registered a pH of 1.8; normal ranges in the gastrointestinal tract are between 7.4 to 6.7, depending on where the sample is taken. The consequences of this difference were substantial, primarily leading to significant gastrointestinal distress. Overall, the vast majority of the autistic subjects (67 percent) reported more frequent episodes of diarrhea and constipation than the healthy subjects. Considering the extreme disparity in microbiome makeup that correlates to these symptoms, restoring a normal microbiome might be the key to easing gastrointestinal distress.
Presently, there are no FDA-approved medications designed to target the gut microbiome of autistic individuals. However, new therapies isolated from natural substances produced by the body are increasingly promising avenues of research. Among these new therapies, butyric acid has achieved early analytical successes in the laboratory.
Researchers have long known that butyric acid is an intercellular signaling molecule and immunoregulator; the body produces butyric acid to use in these capacities. More recently, however, butyric acid was identified as a modulator of gene expression in autism in a 2015 study published in Microbial Ecology in Health and Disease.
This study revealed butyric acid’s ability to govern the behavior of cells in the gut by linking the level of butyric acid to intestinal cells’ ability to produce energy. In the estimation of the study’s authors—and their peers—80 percent of autistic individuals exhibit abnormalities in their cellular mitochondria, the component of the cell that produces cellular energy. These abnormalities can range from excessive throughput of energy to significantly inhibited energy production. Depending on the cell that has malfunctioning mitochondria, the resulting impact on organ tissues can vary.
For example, in white blood cells, abnormal energy production can result in an inability to ward off infection, or, alternatively, excessive inflammatory response. An excessive inflammatory response can cause intense discomfort and bloating for patients, while also reducing the ability of the intestines to absorb nutrients and water. More importantly, butyric acid can modulate these mitochondrial extremes and bring them toward a healthier level of activity.* Thus, it might be possible to manage ASD-affiliated gut dysfunction utilizing butyric acid by virtue of its direct beneficial impact on immune function.*
Butyric acid can also improve the health of the gut via another mechanism; i.e., by modulating the behavior of the white blood cells in the colon the microbiome of autistic individuals can be normalized with regard to the proportions of the bacterial colonies. Because the white blood cells affected by butyric acid will generate a more normal inflammatory response, the normal and healthy bacterial populations of the microbiome can flourish.*
When the normal bacterial populations in the gut are given optimal conditions for them to grow, they can generally out-compete the potentially harmful aberrant bacteria and thus promote better gut health, alleviating GI symptoms. Significantly, for some autistic individuals, this positive reduction of gastrointestinal symptoms might also produce meaningful emotional and behavioral changes as their physical distress is alleviated.*
Microbiome therapeutics is a rapidly developing field, and many questions remain regarding butyric acid’s beneficial impact on the microbiome and the cells responsible for the microbiome’s cultivation. At present, although researchers are unambiguous that butyric acid can induce beneficial genetic changes in colonocytes that modulate their metabolic activity, the nature of these changes is an area of active investigation.
However, the current evidence combined with the knowledge that autistic individuals are typically deficient in butyric acid suggest that it would be prudent to begin butyric acid supplementation even now. Although rigorous clinical trials of butyric acid supplementation are still in progress, taking advantage of the anticipated benefits is likely to achieve multidimensional symptom support and, ultimately, enhanced quality of life.*
The power of Tesseract supplements lies in enhancing palatability, maximizing bioavailability and absorption, and micro-dosing of multiple nutrients in a single, highly effective capsule. Visit our website for more information about how Tesseract’s products can help support your gastrointestinal health.*
Finegold SM, Molitoris D, Song Y, et al. 2002. Clinical Infectious Diseases. 35.
Frye RE, Rose S, Slattery J, Macfabe DF. 2015. Microbial Ecology in Health & Disease. 26.
Giulivi C, Zhang Y-F, Omanska-Klusek A, et al. 2010. Mitochondrial dysfunction in autism. Jama. 304.
Horvath K, Perman JA. 2002. Current Gastroenterology Reports. 4:251–258.
Molloy CA, Manning-Courtney P. 2003. Autism. 7:165–171.