A quarterly publication of the Autism Research Institute

The Autism Research Review International is quarterly publication of the Autism Research Institute

Summer, 2019 | Number 3, Volume 33

Common food additive damages brain cells, may play role in autism spectrum disorders

A commonly used food preservative may play a role in autism spectrum disorders (ASD), according to a new study. 

The preservative, propionic acid (PPA), is used to increase the shelf life of packaged foods and inhibit mold in commercially processed cheese and bread. Latifa Abdelli and colleagues note that while PPA is also produced naturally by the body, eating foods high in PPA can lead to increased gut levels in pregnant women that can cross to the fetus. 

The researchers point out that elevated levels of PPA have been found in the stools of individuals with ASD. Additionally, they note that a disorder called propionic acidemia (PA), which causes PPA to accumulate in the blood, causes symptoms including seizures, movement disorders, gastrointestinal issues, aloofness, and overall developmental delays. “Interestingly,” they say, “PA and ASD share most of their core symptoms with multiple case studies reporting ASD as a comorbidity to PA.” The researchers also note that PPA is believed to cause mitochondrial dysfunction, a problem that affects more than 30% of individuals with ASD. 

To explore the effects of elevated PPA on the developing brain, the researchers exposed neural stem cells to excessive PPA and discovered that this exposure damages brain cells in two ways: 

• It disrupts the natural balance between brain cells by reducing the number of neurons and causing gliosis (an overproduction of glial cells). This excess of glial cells alters connectivity between neurons and causes inflammation. 

• It shortens and damages pathways that neurons use to communicate with the rest of the body. 

The researchers say these effects impair the brain’s ability to communicate and could result in behaviors that are often seen in children with ASD, including repetitive behavior, mobility issues, and an inability to interact with others. 

They conclude, “Clearly, the data supports a significant role for PPA in modulating human neural stem cell patterning leading to gliosis, disturbed neuro-circuitry, and inflammatory response as seen in ASD.” However, they say more research is needed to clarify the possible relationship between PPA and ASD. Their next step, they say, will be to see if a maternal diet high in PPA causes autism in mice genetically predisposed to the condition.


“Propionic acid induces gliosis and neuroinflammation through modulation of PTEN/AKT pathway in autism spectrum disorder,” Latifa S. Abdelli, Aseela Samsam, and Saleh A. Naser, Nature Scientific Reports, June 19, 2019 (free online). Address: Saleh A. Naser, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32816, [email protected]


 “Processed foods may hold key to rise in autism,” news release, University of Central Florida,  June 20, 2019.