Probiotics and Autism Spectrum Disorder

Oct 21 Sean Orr, M.D.

Autism Spectrum Disorder and the Gut-Brain Axis

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder characterized by deficits in social interactions and communication, and certain repetitive behaviors. The prevalence of ASD has been on the rise globally, but its exact causes remain elusive.

Recent research has highlighted the gut-brain axis—a bidirectional communication system between the gastrointestinal (GI) tract and the central nervous system—as a key player in the development of ASD symptoms. The gut-brain axis, mediated by microbiota, immune signals, and neurotransmitters, is thought to influence neurodevelopmental processes, making it a promising target for intervention.

Probiotics are live microorganisms that confer health benefits to the host, and the are gaining attention for their potential to modulate the gut-brain axis and improve ASD symptoms. This essay explores the role of probiotics and prebiotics, such as fructo-oligosaccharides (FOS), in ameliorating ASD symptoms, drawing insights from both human and animal studies, including research on zebrafish models [1].

The Role of Probiotics in Modulating Gut Microbiota

Numerous studies have found that individuals with ASD often exhibit gut dysbiosis, characterized by an imbalance in beneficial and harmful bacteria. For instance, Wang et al. [2] identified lower levels of beneficial bacteria such as Bifidobacterium longum and higher levels of pathogenic bacteria such as Clostridium in children with ASD. This microbial imbalance is associated with both gastrointestinal distress and cognitive-behavioral impairments in ASD patients.

Probiotic supplementation has been shown to restore gut microbial balance by increasing beneficial bacteria and reducing harmful ones. For example, Sivamaruthi et al. [3] reported that probiotics like Lactobacillus plantarum and Bifidobacterium longum improved gut health in children with ASD, resulting in better stool consistency, reduced GI symptoms, and enhanced behavioral outcomes. This suggests that probiotics may alleviate some of the core symptoms of ASD by modulating gut microbiota.

Short-Chain Fatty Acids (SCFAs) and Their Impact on ASD

Short-chain fatty acids (SCFAs), including butyrate, propionate, and acetate, are important microbial metabolites produced by gut bacteria during the fermentation of dietary fibers. These SCFAs are critical for maintaining gut health and modulating brain function via the gut-brain axis. In children with ASD, Wang et al. [4] observed significantly lower levels of SCFAs, which were associated with heightened severity of GI and neurological symptoms.

Probiotic interventions, particularly when combined with prebiotics like FOS, can elevate SCFA levels in the gut. In Wang’s study, children with ASD who received probiotics and FOS supplementation showed significant increases in butyrate, propionate, and acetate, leading to improved GI function and reductions in ASD symptoms. These findings highlight the role of SCFAs in regulating both gastrointestinal and neurological health, and suggest that probiotics and prebiotics may help restore SCFA levels in ASD patients.

Neurotransmitter Regulation via the Gut-Brain Axis

The gut microbiota is closely linked to the production and regulation of key neurotransmitters, including serotonin and dopamine, which play crucial roles in mood, cognition, and behavior [5]. Altered levels of these neurotransmitters are often observed in individuals with ASD. For instance, children with ASD frequently exhibit a hyper-serotonergic state and impaired dopamine metabolism, as observed in Wang et al.

Probiotics have been shown to modulate neurotransmitter levels. Wang et al. demonstrated that after probiotics and FOS intervention, serotonin levels decreased and dopamine metabolism improved in children with ASD [6]. These changes correlated with reductions in ASD symptom severity, suggesting that probiotics can influence neurotransmitter systems via the gut-brain axis. Additionally, research on zebrafish models of ASD has provided further evidence that probiotics can modulate the expression of genes related to neurotransmitter pathways, such as gamma-aminobutyric acid (GABA), serotonin (5-HT), and dopamine (DA), contributing to improved neurobehavioral outcomes [7].

Fulvic acid, a natural compound derived from decomposed organic matter, has garnered attention for its potential benefits on brain function through its influence on the gut-brain axis. The gut-brain axis is a complex communication network linking the gastrointestinal tract and the central nervous system, where gut health significantly impacts neurological function. Fulvic acid's ability to modulate gut microbiota and enhance gut barrier function may indirectly support brain health by reducing systemic inflammation and promoting a balanced microbial environment.

A study published in 2021 demonstrated that humic substances, including fulvic acid, can modulate inflammation and improve barrier function in intestinal epithelial cells [8]. By strengthening the gut barrier and reducing intestinal inflammation, fulvic acid may help prevent the translocation of pro-inflammatory molecules into the bloodstream, which is linked to neuroinflammation and cognitive decline. While direct evidence on fulvic acid's impact on brain function via the gut-brain axis is still emerging, these findings suggest that its beneficial effects on gut health may have positive implications for neurological well-being.

Zebrafish Models and Insights into Probiotic Efficacy

Zebrafish models have become valuable tools in studying the effects of probiotics on ASD-like behaviors and neurodevelopment. The study conducted by Zheng et al. (2022) utilized germ-free (GF) and conventionally raised (CR) zebrafish, as well as mutant strains linked to ASD, to assess the impact of probiotics. Their findings demonstrated that probiotics such as Lactobacillus plantarum and Lactobacillus rhamnosus improved developmental indices (e.g., body length, weight) and mitigated abnormal behaviors in zebrafish models.

Moreover, probiotics significantly influenced the expression of key neurotransmitter-related genes, such as gad1b (involved in GABA production), th (related to dopamine), and tph1a (involved in serotonin synthesis). These gene expression changes suggest that probiotics can directly modulate neurotransmitter systems, which are implicated in the development of ASD symptoms. These findings from zebrafish models provide valuable mechanistic insights into how probiotics may benefit individuals with ASD by targeting the gut-brain axis [9].

Conclusion: Probiotics as a Promising Therapeutic Approach

The emerging body of research underscores the potential of probiotics and prebiotics in modulating the gut-brain axis to improve both GI and neurobehavioral symptoms in individuals with ASD. Studies on both human subjects and animal models, including zebrafish, demonstrate that probiotics can restore microbial balance, elevate SCFA levels, and regulate neurotransmitter production, leading to improved ASD symptoms.

While the current findings are promising, further research is needed to determine optimal strains, dosages, and combinations of probiotics and prebiotics for ASD management. Future studies should also explore the long-term effects of these interventions and their potential to complement existing therapeutic approaches for ASD.

How Action Potential Supplements Can Support You

At Action Potential Supplements, we are dedicated to harnessing the power of natural ingredients to support brain health. Our probiotics are formulated to provide you with the highest quality benefits:

Probiotic 40 Billion with Prebiotics:

A blend of four probiotic strains: Lactobacillus acidophilus, Bifidobacterium lactis, Lactobacillus plantarum, and Lactobacillus paracasei.
Together, they provide a high level of beneficial bacteria to the gut to support a healthy metabolic response for both men and women.

Fermented Mushroom Blend

A premium product featuring six different types of organically grown, fermented mushrooms in their full-spectrum state.
The pre-digested, fermented organic mushrooms in this product offer a wide range of naturally occurring vitamins, minerals, and immunomodulating polysaccharides.
Our Fermented Mushroom Blend features mushrooms that have been micro-cultured through a unique probiotic fermentation process, aiding in digestion and allowing the beneficial immune support compounds, such as polysaccharides, to be easily digested and immediately absorbed in their most bioavailable form and at their peak activity.

Fulvic Acid

Rich in fulvic acids and polyphenols, naturally occurring compounds from Birch Chaga and Pine Bark extract, these capsules are beneficial for maintaining a balanced gut microbiome.

Conclusion

Improving the brain-gut relationship represents a promising natural option for those looking to support cognitive function, neuroprotection, and overall brain health. Backed by historical use and emerging scientific research, our neuronutrients offer a potential addition to a holistic wellness regimen.

Disclaimer: The information provided in this blog post is for educational purposes only and is not intended as medical advice. The statements have not been evaluated by the Food and Drug Administration. Products mentioned are not intended to diagnose, treat, cure, or prevent any disease. Please consult a qualified healthcare professional before starting any new supplement, especially if you have existing health conditions or are taking medications.

References

Bu, L. K., Jia, P. P., Huo, W. B., & Pei, D. S. (2024). Assessment of Probiotics' Impact on Neurodevelopmental and Behavioral Responses in Zebrafish Models: Implications for Autism Spectrum Disorder Therapy. Probiotics and antimicrobial proteins, 10.1007/s12602-024-10335-y. Advance online publication. https://doi.org/10.1007/s12602-024-10335-y
Wang, Y., Li, N., Yang, J. J., Zhao, D. M., Chen, B., Zhang, G. Q., Chen, S., Cao, R. F., Yu, H., Zhao, C. Y., Zhao, L., Ge, Y. S., Liu, Y., Zhang, L. H., Hu, W., Zhang, L., & Gai, Z. T. (2020). Probiotics and fructo-oligosaccharide intervention modulate the microbiota-gut brain axis to improve autism spectrum reducing also the hyper-serotonergic state and the dopamine metabolism disorder. Pharmacological research, 157, 104784. https://doi.org/10.1016/j.phrs.2020.104784
Sivamaruthi, B. S., Suganthy, N., Kesika, P., & Chaiyasut, C. (2020). The Role of Microbiome, Dietary Supplements, and Probiotics in Autism Spectrum Disorder. International journal of environmental research and public health, 17(8), 2647. https://doi.org/10.3390/ijerph17082647
Wang, Y., Lee, I.S., Braun, C., Enck, P. (2016). Effect of probiotics on central nervous system functions in animals and humans: A systematic review. Journal of Neurogastroenterology and Motility, 22(4), 589-605. https://doi.org/10.5056/jnm16018
Santocchi, E., Guiducci, L., Fulceri, F., Billeci, L., Buzzigoli, E., Apicella, F., Calderoni, S., Grossi, E., Morales, M. A., & Muratori, F. (2016). Gut to brain interaction in Autism Spectrum Disorders: a randomized controlled trial on the role of probiotics on clinical, biochemical and neurophysiological parameters. BMC psychiatry, 16, 183. https://doi.org/10.1186/s12888-016-0887-5
Guevara-Gonzaléz, J., Guevara-Campos, J., González, L., & Cauli, O. (2022). The Effects of Probiotics and Prebiotics on Gastrointestinal and Behavioural Symptoms in Autism Spectrum Disorder. Current reviews in clinical and experimental pharmacology, 17(3), 166–173. https://doi.org/10.2174/2772432816666210805141257
Zheng, J., Long, F., Cao, X., Xiong, B., Li, Y. (2022). Knockout of Katnal2 leads to autism-like behaviors and developmental delay in zebrafish. International Journal of Molecular Sciences, 23(15), 8389. https://doi.org/10.3390/ijms23158389
Riede, S., Bogdanova, A., Krüger, M., & Westphal, C. (2021). Humic substances modulate inflammation and improve barrier function in intestinal epithelial cells. Journal of Animal Physiology and Animal Nutrition, 105(S1), 27–35. https://doi.org/10.1111/jpn.13507
Guan, Y., Tang, G., Li, L., Shu, J., Zhao, Y., Huang, L., & Tang, J. (2024). Herbal medicine and gut microbiota: exploring untapped therapeutic potential in neurodegenerative disease management. Archives of pharmacal research, 47(2), 146–164. https://doi.org/10.1007/s12272-023-01484-9