Gluten May or May Not Play a Role in Autism, But Study Finds Link in Immune System Marker
Autism is a neurodevelopment disorder that negatively affects communication and social interaction. The cause is not known; in fact, there may be several confounding factors that come together that cause the condition to occur. In addition to genetics, it appears that the immune system also plays a role in a subset of patients.
One area of interest is the role that gluten might play in the exacerbation of symptoms.
Gluten is a group of more than 70 proteins found in wheat and related grains. Those with a specific allergic reaction to consumption of gluten have a disease known as celiac disease, where the digestive system is damaged every time a person eats a food containing gluten. There are also patients known as having a gluten intolerance – they have unfavorable consequences after eating certain grains such as digestive upset or neurologic symptoms.
Parents of children with autism sometimes try a gluten-free diet to attempt to improve behavior. Studies are conflicting as to whether these are truly effective, but one theory suggests that autistic persons cannot properly digest the gluten which then forms substances that act like opiates, altering behavior and responses to their outer environment.
There is also a high rate of gastrointestinal issues among children with autism. Painful conditions such as constipation, bloating, and diarrhea can trigger problem behaviors as well as feeding difficulties.
In an attempt to find a link between gluten and autistic behavior, researchers with Columbia University Medical Center evaluated blood samples from 140 children, thirty-seven of which were diagnosed with an autism spectrum disorder. Blood samples were tested for antibodies to tissue transglutaminase, a sensitive and specific marker of celiac disease, as well as antibodies to gliadin (a component of gluten).
The team found that children with autism showed elevated levels of antibodies produced by the immune system in response to gluten consumption. However, the children did not have true celiac disease, as they tested negative for the antigen markers.
"The IgG antibody response to gluten does not necessarily indicate sensitivity to gluten or any disease-causing role for the antibodies in the context of autism," said Dr. Armin Alaedini PhD, an assistant professor of medical sciences in the Department of Medicine and the Institute of Human Nutrition. "But the higher levels of antibody to gluten and their association with gastrointestinal symptoms point to immunologic and/or intestinal permeability abnormalities in the affected children."
“By themselves, these antibodies do not mean disease,” adds Dr. Dan Coury, medical director of Autism Speaks Autism Treatment Network. “However, when high levels occur with other symptoms, we begin to get a clearer picture.” The research may also offer new clues on how to identify patients who would most benefit from certain treatment strategies, such as the adoption of a gluten-free diet.
Nga M. Lau, Armin Alaedini et al. Markers of Celiac Disease and Gluten Sensitivity in Children with Autism. PLoS ONE, 2013; 8 (6): e66155 DOI:10.1371/journal.pone.0066155