Last week, I highlighted new evidence about the link between gluten and the symptoms of autistic spectrum disorder (ASD). Hot off the presses, we have another study about a gut-autism link. Researchers at Arizona State University (1) found a significant difference between the normal flora (bacteria in the gastrointestinal tract) of children with autism and non-autistic children. In particular, autistic children had lower levels of three types of bacteria: Prevotella, Coprococcus, and Veillonellaceae. These were identified from fecal samples taken from children ages 3 to 16 years. These organisms, especially Prevotella, are important for carbohydrate digestion, and maintenance of healthy biodiversity in the gut ecosystem. Impairment of carbohydrate digestion may leave these kids more susceptible to developing the leaky gut and gluten sensitivity described in last week’s article.
While this research is intriguing, it still presents us with a chicken-or-egg dilemma: do disturbances of gut bacteria contribute to the development of ASD, or are children with ASD more susceptible to gut flora imbalances by some other mechanism? We are only in the very early stages of identifying all the complexities of the trillions of microorganisms that live inside of us. Now that we have identified the human genome, the next step is to tackle the human microbiome: the identification of all of those microbial species in their proper proportions to maintain good health.
Over the next 20 years or so, our current probiotics supplements will look like primitive stone tools. Hopefully, we can get to the stage where we can supplement with specific organisms like the ones identified in this study (none of which are available in current probiotics supplements). Otherwise, we may have to look more seriously at fecal microbiota transplantation as an important technique for many health conditions, not just C. difficile infection.
1. Kang D-W, Park JG, Ilhan ZE, Wallstrom G, LaBaer J, et al. (2013) Reduced Incidence of Prevotella and Other Fermenters in Intestinal Microflora of Autistic Children. PLoS ONE 8(7): e68322. doi:10.1371/journal.pone.0068322