Our gut plays host to an astounding number of microbes including fungi, viruses, and hundreds of species of bacteria. This relationship isn’t all one-way. In return for providing them with food and shelter, these bacteria help defend us from their harmful disease-causing cousins and help us break down our food. A new study has found that their benefits may even reach our brain.
Children with autism and associated neurological disorders not only have trouble with communication and behaviour, but also commonly suffer from gastrointestinal problems like constipation and diarrhea. Since having a healthy and diverse population of gut microbes can alleviate gastrointestinal symptoms, it is not surprising that a number of studies have shown that children with autism have a different composition of gut microbes compared to the average child.
Although this may seem surprising, there’s growing support for the idea that the benefits of having a healthy gut microbe population extend to regions far from the gut. For instance, a 2016 systematic survey found that taking probiotics (dietary supplements that include such bacteria) can help patients with anxiety, depression, and other behavioral disorders. In a 2013 experiment, autism-like behaviour in mice was eased by oral doses of one gut bacterium. We don’t yet know if an abnormal composition of gut microbes can cause autism, but it certainly seems to exacerbate its symptoms.
But hold off on ordering probiotic supplements in bulk. This study only looked at 18 children, and had no control group of children who were not given the transplant. Furthermore, this study extracted microbes from (carefully screened and treated) fecal matter and then transplanted it to half the children in the study via the rectum (the other half got it orally). However, it does open the door to larger studies, and the development of different interventions. We may soon find that a healthy gut is a key ingredient to a functioning society.