This article points out that gut bacteria studied in mice have an effect on multiple brain related conditions. It’s too soon to say if there will be any treatments to come out of this research, but clearly the gut microbiome is closely related to brain conditions.
“Now researchers are pinpointing individual strains that seem to have an effect.
To study autism, Dr. Mauro Costa-Mattioli and his colleagues at the Baylor College of Medicine in Houston investigated different kinds of mice, each of which display some symptoms of autism. A mutation in a gene called SHANK3 can cause mice to groom themselves repetitively and avoid contact with other mice, for example.
In another mouse strain, Dr. Costa-Mattioli found that feeding mothers a high-fat diet makes it more likely their pups will behave this way.
When the researchers investigated the microbiomes of these mice, they found the animals lacked a common species called Lactobacillus reuteri. When they added a strain of that bacteria to the diet, the animals became social again.
Dr. Costa-Mattioli found evidence that L. reuteri releases compounds that send a signal to nerve endings in the intestines. The vagus nerve sends these signals from the gut to the brain, where they alter production of a hormone called oxytocin that promotes social bonds.
Other microbial species also send signals along the vagus nerve, it turns out. Still others communicate with the brain via the bloodstream.
It’s likely that this influence begins before birth, as a pregnant mother’s microbiome releases molecules that make their way into the fetal brain.
Mothers seed their babies with microbes during childbirth and breast feeding. During the first few years of life, both the brain and the microbiome rapidly mature.”