While many people are aware of the behavioral symptoms associated with autism, probably not so many realize that people with autism often also have gastrointestinal problems. With that in mind, scientists at the University of Arizona recently conducted a study in which a group of 18 autistic children received fecal transplants from donors with healthy gastrointestinal systems. Not only did the procedure help to "rebalance" their gut flora, but it also improved their behavior.

First of all, a fecal transplant is just what it sounds like. Feces from one person are screened for disease-causing organisms, and then introduced into the recipient's digestive tract. In this case, the recipients first took antibiotics for two weeks, to wipe out their existing gut flora. They then received the fecal transplant initially in a high-dose liquid form, after which it was delivered in a lower-dose powder mixed into smoothies.

Such transplants have worked in the past for other people with gastrointestinal problems, and they did so in this case, too. In the eight weeks following the end of the treatment, parents reported a substantial decrease in their children's bouts of gut problems such as diarrhea and stomach pain.

Interestingly, though, they also observed substantial improvements in their behaviour. Using questionnaires designed to assess social skills, irritability, hyperactivity, communication and other factors, it was found that the average developmental age of the children (aged 7 to 16 years) increased by an average of 1.4 years.

This was backed up by observations from the children's doctors, who noted that their psychological autism symptoms had decreased 22 percent by the end of the treatment, and by 24 percent eight weeks later.

Their gut flora, meanwhile, now consisted of the same viruses and bacteria as that of a non-autistic control group that also received the transplants. Ordinarily autistic children tend to have less of some types of important bacteria, and less bacterial diversity overall, likely due to their being put on antibiotics early in life.

Previous research has suggested that gut flora has an effect on how the brain works, and that certainly seems like it could be the case here. The way in which it does so, though, is still not fully understood.

The study, which was led by Ann Gregory (who is now a microbiology graduate student at The Ohio State University) and Matt Sullivan, along with researchers from Arizona State University and Northern Arizona University, is described in a paper recently published in the journal Microbiome. The scientists are currently seeking funding to conduct a larger-scale study.