We’ve long known that the human stomach can be a trustworthy indicator of our mental state, and vice-versa. Whether it’s a poor, nutrient-deficient diet leading to a groggy and depressive state or a grindingly stressful situation leading to a range of intestinal issues, the connection between the brain and the gut is both intimate and deep.

Yet new research has revealed an ever-increasing number of remarkable connections between such problems as depression, post-traumatic stress disorder (PTSD), and autism, and our stomach health.

As the connection between the gut microbiome and human health appears increasingly multi-layered, novel solutions to human ailments have come to light–including the recent study by scientists at Arizona State University (ASU) that shows how a boost in microbial diversity in the stomach through fecal transplants can dramatically cut down on the symptoms of autism in young children.

Not only does the severity of issues arising from Autism Spectrum Disorder (ASD) dramatically fall post transplant, it does so for several years after the transplants are undertaken, showing the huge power of the gut microbiome in regulating and affecting conditions in the brain.

According to the Centers for Disease Control and Prevention, about one in every 59 children born in the United States is diagnosed with autism. The neurological condition can lead to a number of social and communicative difficulties for children, with chronic gastrointestinal issues among the many problems they face, with around 30 to 50 percent of those with autism experiencing problems like constipation, stomach pain, and diarrhea, according to the authors of the study at ASU.

In an ASU study from 2017, 15 of 18 children with severe symptoms arising from autism were given eight weeks of fecal transplants in order to introduce healthy microbial flora into the participants’ gastrointestinal tracts. Two years later, only three of the participants remain classified as suffering “severe” symptoms, measured through questionnaires that gauged their communication, social skills, hyperactivity, and other factors.

Rosa Krajmalnik-Brown, a scientist at ASU told New Atlas:

“Many kids with autism have gastrointestinal problems, and some studies, including ours, have found that those children also have worse autism-related symptoms … In many cases, when you are able to treat those gastrointestinal problems, their behavior improves.”

Indeed, the benefits of the fecal transplant have gone beyond simply persisting, but have actually improved with time. While doctors had observed a 24-percent decrease in psychological symptoms of autism at the eight-week mark, two years after the study was held those same symptoms were nearly cut in half, or 45 percent.

Krajmalnik-Brown continued:

“We are finding a very strong connection between the microbes that live in our intestines and signals that travel to the brain … Two years later, the children are doing even better, which is amazing.”

And while many argue that autism isn’t necessarily a disorder requiring a “cure,” per se, it remains inarguable that the removal of social, communicative, and gastrointestinal difficulties will serve to make the lives of people on the spectrum easier.

The scientists have begun working to begin larger and more thorough clinical trials in hopes of continuing to prove the benefits of fecal transplants, as well as clearing their treatment with the FDA.