Researchers have found 32 toxic metabolites that are “significantly elevated” in children on the autism spectrum.
The team said most autistic children have around seven toxic metabolites “at extremely elevated levels”.
Professor James Adams is trying to raise $20m for his FMT treatment for autism
Professor James Adams, of Arizona State University, led the team.
Toxins affect brain and body
In his review study, Adams said the toxins affect chemical messages in the brain. These toxins had a major impact on thinking, attention, mood, behaviour and sleep.
One of the metabolites, p-cresol sulphate, is a byproduct of gut bacteria breaking down proteins. It is “significantly higher” in around one in four (25 per cent) of children on the autism spectrum.
As well as affecting the brain, the metabolite adversely impacts the gut, mitochondria, kidneys, liver and immune system. It causes autism symptoms when given to mice.
Improvements with stool transplants
But Adams says faecal or stool transplants can “greatly reduce” the levels of p-cresol sulphate down to normal levels.
The researcher says the treatment also causes “major improvements” in autism and gut health.
Adams first trialled the treatment, known as faecal microbiota transplant (FMT), in 2017. He did a follow-up study with the same 18 children two years later.
Trial results
The researcher, who has an adult autistic daughter, maintains this first trial saw eight out of 18 children (44 per cent) lose their autism diagnosis in the follow-up study.
He later trialled the faecal microbiota transplant (FMT) treatment on 51 adults.
Overall, he found the treatment had a “moderate effect” on improving autism and gut symptoms.
He said he needs $20 million for his company, Gut-Brain-Axis Therapeutics (GBAT), to fund a final phase three trial.
‘Growing body of evidence’
In a statement, biomedical charity Thinking Autism said Adams’s work “adds to a growing body of evidence” for the benefits of FMT treatment.
Adams’s team also ran a trial on children with Pitt-Hopkins Syndrome. It is a genetic disorder causing a severe learning disability, autism and constipation.
The drug was said to be safe and well tolerated and saw a “substantial improvement” in all six of the children involved.
Adams’ review study was published this month in the International Journal of Molecular Science.
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Published: 20 February 2025
