LOS ANGELES - Researchers with the University of Central Florida believe there may be a link between a preservative in processed foods and autism.
In a study published in the journal Nature, the researchers exposed human neural stem cells to high levels of the food preservative Propionic acid, or PPA, over the course of 18 months. They found PPA, which is found in processed foods, reduced neuron development.
The researchers indicated that pregnant women who consume too much processed food rather than home-made meals could cause effects in a fetus' brain development and increase the risk of autism.
Researchers said that when PPA circulates through the blood system to the brain, it passes the brain's blood barrier and changes multiple cell-signaling processes, including energy metabolism, neurotransmitter synthesis and release, and lipid metabolism. Excessive levels of PPA can be toxic in the brain, according to the study.
When researchers exposed the human neural cells to high amounts of PPA, they found the neurons overproduced glial cells, which are cells that surround neurons and provide support for communication between the cells. Too many glial cells can cause a disruption in the brain and even cause inflammation.
In the study, researchers hypothesized that high levels of PPA "may tamper with" neural cell development that could lead to overproduced glial cells and brain inflammation that disrupts "neural connectivity, similar to (autism spectrum disorder)."
In the past, studies have been done with PPA by exposing rats to the fatty acid during different stages of development in an effort to recreate behaviors similar to those with autism.
Nearly one in 59 children are diagnosed with a form of autism in the U.S., according to the Centers for Disease Control and Prevention. That number has increased significantly from one in 150 children in 2000.
It's still unclear what causes autism, but it's believed that genetic predispositions, environmental causes and immune system abnormalities for a mother during early pregnancy are major factors.