Researchers from the University of Central Florida have found a molecular connection between a common food preservative in processed foods, neuronal disruption, and autism. These findings suggest that there may be a link between the consumption of processed foods during pregnancy and the rise of autism.

The prevalence of autism spectrum disorder (ASD) is on the rise and researchers agree there is no one exclusive cause of ASD. It might be a combination of genes, environmental influences, and problems with the maternal immune system in the early stages of pregnancy. Now, UCF researchers have discovered how high levels of Propionic Acid (PPA) reduce the development of neurons in fetal brains.

A mother’s microbiome changes during pregnancy and can cause increases PPA, but eating packaged foods containing the preservative can further increase PPA in the woman’s gut. PPA increases the shelf life of packaged foods and inhibits mold in commercially processed cheese and bread.

UCFs Dr Saleh Naser, Latifa Abdelli and undergraduate research assistant Aseela Samsam have published these finding in Scientific Reports. Dr Naser, who specializes in gastroenterology research, began the study after reports showed that autistic children often suffer from gastrointestinal issues such as constipationdiarrhea, and abdominal pain. He wondered about a possible link between the gut microbiome and the development of ASD.

“Studies have shown a higher level of PPA in stool samples from children with autism and the gut microbiome in autistic children is different,” Dr Naser said for UCF News. “I wanted to know what the underlying cause was.”

His research group has found that exposing neural stem cells to excessive PPA damages brain cells. It results in a reduced number of neurons and over-production of glial cells, which disturbs the natural connectivity between neurons. Rise in PPA also causes inflammation, which has been found in the brains of autistic children. Furthermore, excessive PPA shortens and damages pathways that neurons use to communicate with the rest of the body. The combination of a reduced number of neurons and the damaged pathways results in repetitive behavior, mobility issues and inability to interact with others.

This 18-month study is the first to discover the molecular link between elevated levels of PPA, the proliferation of glial cells, disturbed neural circuitry, and autism. Dr Naser and Abdelli said more research needs to be done before drawing clinical conclusions. They will validate findings in mice models next, to investigate whether a high-PPA maternal diet causes autism in mice genetically predisposed to the condition.

There is no cure for autism, which affects about 1 in 59 children, but there is hope for a better understanding of the disorder and better prevention.

“This research is only the first step towards better understanding of Autism Spectrum Disorder,” the UCF scientists concluded. “But we have confidence we are on the right track to finally uncovering autism etiology.”

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By Andreja Gregoric, MSc