Autism affects people’s social behaviour and communication, and may impair their ability to learn things. All this is well known. Less familiar to most, though, are the gastrointestinal problems associated with the condition. The intestines of children with autism often harbour bacteria different from those in the guts of the neurotypical. As a consequence, such people are more than three times as likely as others are to develop serious alimentary-canal disorders at some point in their lives.
Unfortunate though this is, the upset gut floras of autistic people are seen by some investigators as the key to the condition—and to treating it. Recent research has shown that altering animals’ intestinal bacteria can have dramatic effects on their nervous systems. Ameliorating autism by tinkering with the ecology of the gut might thus be a fruitful line of inquiry.
A study just published in Neuron suggests that it is. In it, Mauro Costa-Mattioli of Baylor College of Medicine, in Texas, and his colleagues demonstrate that introducing a particular bacterium into the guts of mice that display autistic symptoms can abolish some of those symptoms. The bug in question is Lactobacillus reuteri. It is commonly found in healthy digestive systems and helps regulate acidity levels. And it is also easily obtainable for use as a probiotic from health-food shops.
.. Clearly, autism in people is more complicated than a mere willingness to associate with others. And getting too excited about a mouse trial is usually a mistake. But in Dr Costa-Mattioli’s view his results, which have been replicated in part by Evan Elliot’s laboratory in Bar-Ilan University, Israel, would justify embarking on at least preliminary trials intended to determine whether L. reuteri has positive effects on people with autism, and might thus be worth pursuing.
Others agree. Sarkis Mazmanian of the California Institute of Technology works in the same area. He says of these results: “I think the bar is now very low for getting this research moved on to human trials since most people already have these bacteria inside them and we know there are few, if any, safety or toxicity issues.”