Introduction of the probiotic bacteria Bacteroides fragilis into the digestive tract improves gastrointestinal function and behavioral symptoms in an animal model, suggesting that the bacteria may be a potential probiotic therapy in humans with neurodevelopmental disorders, according to a recent study published in the journal Cell.1 This study has particular implications for autism spectrum disorders (ASDs), but the researchers say that the study results might be applicable to various disorders.

The researchers used a mouse model that mimics some of the behavioral, physiological, and gastrointestinal signs and symptoms found in individuals with autism. They introduced the beneficial bacterium Bacteroides fragilis into the digestive tracts of these mice and found that behavior improved along with a correction of gut permeability (leaky gut) and an improvement in the microbial composition (gut balance).

“We propose the transformative concept that autism, and likely other behavioral conditions, are potentially diseases involving the gut that ultimately impact the immune, metabolic, and nervous systems, and that microbiome-mediated therapies may be a safe and effective treatment for these neurodevelopmental disorders,” they stated.

Autism affects 1 in 88 children born in the United States, a number that has rapidly climbed over the past few decades. Digestive distress is a common symptom among these children, particularly in those with more severe symptoms.2 These digestive symptoms are thought to be the result of gut bacterial imbalance, or dysbiosis.3 More studies will be taking a closer look at the effects of modifying gut balance with probiotics, both in humans and animals.

Current integrative medical treatment of autism includes a comprehensive gut clean up protocol that involves removal of pathogens, repair of the gut lining, and replenishment of the probiotic bacteria in the gut. Cleaning up the gut should be the first step in just about any chronic condition, even those outside the gut, such as autism and related neurodevelopmental disorders.

For more on autism, click here to read previous blogs.


  1. Hsiao EY, McBride SW, and Hsien S, et al., “Microbiota modulate behavioral and physiological abnormalities associated with neurodevelopmental disorders.” Cell. 2013 Dec;155(7):1451–1463.
  2. Adams JB, Johansen LJ, and Powell LD, et al., “Gastrointestinal flora and gastrointestinal status in children with autism–comparisons to typical children and correlation with autism severity.” BMC Gastroenterol. 2011 Mar 16;11:22.
  3. Finegold SM, Downes J, Summanen PH, et al., “Microbiology of regressive autism.” Anaerobe. 2012 Apr;18(2):260-2.