The diagnosis and incidence rate of autism spectrum disorder (ASD) continues to rise worldwide 1–7. Along with this rise, clinical research has begun to focus on the roles inflammation 8–16 and alterations in the gut microbiome 2,17–32 may play as risk factors for individuals genetically predisposed to ASD. One possible mechanism suggested to restore the gut microbiome in children diagnosed with ASD are treatment protocols utilizing probiotics.
Probiotics are defined as living microorganisms that, in adequate amounts, confer health benefits to a recipient 33,34. While nothing new, probiotics have gained traction as an option to alter gut microbiota and restore balance in the gut in the 20th century 33–37. Probiotics have demonstrated an ability to restore the balance of the gut microbiota and reduce gut inflammation as well as associated GI symptoms, such as bowel function 33–35,38,39. These positive results have led to an exploration of the possible role probiotics could play in children diagnosed with ASD, who are known to experience more GI issues than their typically developing peers (Learn more about the gut issues in ASD here).
What do we know about probiotic treatments in children with ASD?
Overall, the results from the research to date are inconclusive and do not confirm the proposed benefits of probiotics in children with ASD 40–43. That said, several studies do support the possibility that probiotics may alter autism-related behaviours and/or GI symptoms in children with ASD 44–49. Probiotic treatment (ranging from 3 weeks to 6 months) has been reported to have the capacity to alleviate GI symptoms, such as bloating and abdominal pain 44,45,47,48, and improve bowel function and stool type 46 in children diagnosed with ASD. Additionally, studies have shown improvements in autism-related behaviours after probiotic treatments in children diagnosed with ASD 45,46,48,49. In some cases, these improvements were only seen, or were more pronounced, in children who presented with GI symptoms 45,47.
It is important to note that while the above-highlighted studies provide some support for the role probiotics may play in the treatment of children with ASD, the literature is divided 40–43, with some studies showing no changes in GI symptoms (Parracho et al., 2010;) and/or autism-related behaviours 47,50 after probiotic treatments.
When discussing probiotics, it is important to keep in mind that their engraftment in the gut is reported to be transient, often only present in the gut microbiome when the probiotic(s) are actively being taken and not once they have been discontinued 51,52. In addition, a recent study by Suez et al. found that probiotics can actually delay the recovery of the microbiome after disruption (such as antibiotics) 51,53. In contrast, fecal microbiota transplantation (FMT and autologous FMT) has been shown to accelerate microbiome recovery 51,53. Based on the current clinical data, FMT appears to be a more effective treatment for restoring gut microbiome dysfunction 51.
In summary, our understanding of the role of the gut microbiome and gut-brain axis in ASD is growing with increased clinical research (Learn more about the gut microbiome in ASD here). Research suggests that modulating the gut microbiome may present a treatment avenue to alleviate GI symptoms and possibly autism-related behaviours 54. With this, the interest in possible treatments, such as FMT, which restore a healthy and stable microbial community 55–58, are being increasingly studied in conditions like ASD (Learn more about research around FMT and ASD here).
Our focus at Novel Biome is on supporting autistic children who suffer from digestive symptoms and significant microbiome imbalance to restore their microbiome through Fecal Microbiota Transplantation (FMT).
Team Novel Biome
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