Autism and The Intestinal Microbiome
All mammals possess an invisible organ that, until very recently, science had ignored: The intestinal microbiome. This organ consists of an incredible variety of microorganisms. It’s become clear that we depend on the proper functioning of this microbial organ to survive. However, we’ve barely scratched the surface when it comes to understanding how this conglomerate of microbes helps us.
How does the intestinal microbiome work?
Without a doubt, you know that you have microorganisms living in your body. However, you might not be aware of the magnitude of their actual population. It’s easy to understand that the densest and most diverse community is located in your intestines. However, when you find out that your microbiome is responsible for more than half of the mass of your feces, it’s a little different. Right?
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You have so many microbes that they have the power to complete the process of digesting food. This is the most obvious case, but there are more that will surprise you. Your microbes play a key role in the development of your immune system and also in maintaining its ability to respond. What’s more, they’re responsible for regulating our metabolism.
What do these microbes have to do with the brain?
The answer is quite a lot. Today, science has demonstrated that there exists a microbiotic-intestinal-cerebral axis. What’s more, that its route is two-directional. This means that stress can disturb the composition of our intestinal flora and, at the same time, our intestinal flora can affect our behavior.
Many of these studies have involved rats that were raised “without germs.” These studies demonstrated what happens when conventional microbiota is lacking. It has implications on behavior, gene expression in the brain, and the development of the nervous system.
Other types of studies made use of different antimicrobial agents and their first fecal transplants. These studies demonstrated that differences in the composition of intestinal flora affect behavior. What’s more, they showed that altering the composition of intestinal flora can induce or relieve anxiety.
Today, researchers have made advances in their knowledge on a molecular level. They now know that alterations in the microbiotic ecosystem can induce specific changes in neurotransmitters and their receptors… including serotonin.
What role does the intestinal biome play in autism?
Autism Spectrum Disorder (ASD) refers to an alteration in neurological development. There are two main deficits that characterize this alteration: Deteriorated communication and social interaction. The patient displays restricted and repetitive patterns regarding interests, behaviors, or activities. ASD has a prevalence of between 2 and 20 cases in 1000 throughout the world.
Currently, there is no approved treatment for the central symptoms of autism. People with ASD often have gastrointestinal problems, an alteration in their intestinal microbiome. In concordance with this finding, a number of growing studies have found evidence that suggests an alteration in immune response and of neuroinflammatory mechanisms in patients with ASD.
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The gastrointestinal problems that most people with autism experience support the idea that this disorder has a physiological basis. This leads experts to believe that relieving gastrointestinal problems could also relieve the main symptoms of autism.
And finally, a recent study demonstrated the beneficial long-term effects for children with an ASD diagnosis. This study involved a revolutionary stool transfer known as a fecal microbiota transplant.
Breastfeeding and the composition of the intestinal biome and Autism Spectrum Disorder
Breastfeeding is a determining factor in the composition of an individual’s intestinal biome. Therefore, studying breastfeeding in populations with autism spectrum disorder is an area of interest. A 2019 study explored the relationship between ASD, the initiation of breastfeeding, and its duration. At the moment, it seems that prolonged breastfeeding is a protective factor against ASD, although further studies are needed .It might interest you...
All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.
- Bray, N. (2019). The microbiota–gut–brain axis. Microbiota milestone. Nature Reviews Neuroscience. S22. https://www.nature.com/articles/d42859-019-00021-3
- Akhondzadeh, S. (2019). Microbiota and Autism spectrum disorder. Avicenna journal of medical biotechnology, 11(2), 129.
- Pulikkan J, Mazumder A, Grace T. (2019). Role of the gut microbiome in autism spectrum disorders. Adv Exp Med Biol. 1118:253-269. https://www.ncbi.nlm.nih.gov/pubmed/30747427
- Soke, G. N., Maenner, M., Windham, G., Moody, E., Kaczaniuk, J., DiGuiseppi, C., & Schieve, L. A. (2019). Association Between Breastfeeding Initiation and Duration and Autism Spectrum Disorder in Preschool Children Enrolled in the Study to Explore Early Development. Autism research: official journal of the International Society for Autism Research, 12(5), 816
- Xu, M., Xu, X., Li, J., & Li, F. (2019). Association between gut microbiota and autism spectrum disorder: a systematic review and meta-analysis. Frontiers in psychiatry, 10, 473.
- Soke, G. N., Maenner, M., Windham, G., Moody, E., Kaczaniuk, J., DiGuiseppi, C., & Schieve, L. A. (2019). Association Between Breastfeeding Initiation and Duration and Autism Spectrum Disorder in Preschool Children Enrolled in the Study to Explore Early Development. Autism research: official journal of the International Society for Autism Research, 12(5), 816.
- Kang, D. W., Adams, J. B., Coleman, D. M., Pollard, E. L., Maldonado, J., McDonough-Means, S., … & Krajmalnik-Brown, R. (2019). Long-term benefit of Microbiota Transfer Therapy on autism symptoms and gut microbiota. Scientific reports, 9(1), 5821.