Some children diagnosed with autism spectrum disorder (ASD) may benefit from gluten-free, casein-free diets, according to Penn State researchers.
The new Penn study, published online in the journal Nutritional Neuroscience, found children with autism who switched to restricted diets experienced improvements in behavior and physiological symptoms.
The research is the first to use survey data from parents to document the effectiveness of such diets on children with ASD.
"Research has shown that children with ASD commonly have GI [gastrointestinal] symptoms," said Christine Pennesi, a medical student at Penn State College of Medicine. "Some experts have suggested that [gluten and casein] cause an immune response in children with ASD, and others have proposed [they] could trigger GI symptoms and behavioral problems."
The team -- which included Laura Cousino Klein, associate professor of biobehavioral health at Penn -- surveyed 387 parents or primary caregivers of children with ASD about their children's GI symptoms, food allergies and sensitivities, as well as their children's degree of adherence to a gluten-free, casein-free diet.
The team found that a gluten-free, casein-free diet was effective in improving ASD behaviors, physiological symptoms and social behaviors for those children with GI symptoms and with allergy symptoms. Parents also noted increases in their social behaviors -- communication, eye contact, engagement, attention span, requesting behavior and social responsiveness -- when they strictly followed a restricted diet.
According to Klein, autism may be more than a neurological disease -- it may involve the GI tract and the immune system.
"There are strong connections between the immune system and the brain, which are mediated through multiple physiological symptoms," Klein said. "A majority of the pain receptors in the body are located in the gut, so by adhering to a gluten-free, casein-free diet, you're reducing inflammation and discomfort that may alter brain processing, making the body more receptive to ASD therapies."
Parents who eliminated all gluten and casein from their children's diets reported a greater number of improvements after starting the diet, compared to children whose parents did not eliminate all gluten and casein.
"While more rigorous research is needed, our findings suggest that a gluten-free, casein-free diet might be beneficial for some children on the autism spectrum," Pennesi said. "It is also possible that there are other proteins, such as soy, that are problematic for these children."