Gastrointestinal Problems in Autistic Children: Inherent or Influenced?

Since first described and given a name in 1943, efforts to elicit the true nature of autism have failed, perhaps because its symptoms manifest themselves in each person differently. We have learned that all people with autism have some core symptoms in three areas of development: social interaction, verbal and nonverbal communication, and limited interests in activities or play. Also, various gastrointestinal problems, such as chronic diarrhea, chronic constipation and food intolerances, have been frequently reported in children with the disorder, prompting research into a diet-autism link and inspiring interest in the use of special diets to treat the disorder. But a new study suggests that these stomach problems are not the result of autism itself but of any number of external factors, including “ritualistic tendencies” in eating and medication that autistic children take.

For the study, Mayo Clinic researchers followed 124 children with autism and 248 children without autism until they turned 18. Gastrointestinal problems were classified into five groups: constipation; diarrhea; abdominal bloating, discomfort or irritability; gastroesophageal reflux or vomiting; and feeding issues or selectivity. The frequency of symptoms was about 77 percent in the autism group and 72 percent in their non-autistic counterparts, a difference not considered statistically significant. “We did not find a difference in gastrointestinal symptoms in total,” said Dr. Samar Ibrahim, a fellow in gastroenterology and instructor in pediatrics at the Mayo Clinic and the study’s lead author.

However, the researchers found that nearly 34 percent of the children in the autistic group had constipation, compared with about 18 percent of those without the disorder. About 24 percent in the autistic group had feeding issues, compared to 16 percent of those who weren’t autistic. They said those differences could stem from neurobehavioral issues connected with autism. “The ritualistic tendencies, need for routine, and insistence on sameness that are characteristic of children with autism may lead these children to choose and demand stereotyped diets that may result in an inadequate intake of fiber, fluids, and other food constituents,” they said. “Thus, behaviorally related food selectivity may, in turn, lead to constipation.”

In addition, certain medications that autistic children take can also interfere with appetite and eating. “In our study, around 50 percent of children were on stimulant medications, and those might affect appetite and might have something to do with issues with food,” Ibrahim said.

Keith A. Young, vice chairman for research in the psychiatry and behavioral science department at Texas A&M Health Science Center College of Medicine, said he thought it was interesting that the study showed virtually no indication of celiac disease; only one case in the entire group. A possible link between celiac disease and autism was proposed as far back as 1961.

Dr. Patricia Manning-Courtney, medical director of the Kelly O’Leary Center for Autism Spectrum Disorders at Cincinnati Children’s Hospital Medical Center, said the study is important because it’s the first to scientifically compare the rate of gastrointestinal (GI) problems in an autistic population with that of children who are developing normally. She pointed out, however, that the constipation and feeding difficulties identified in the study are not the symptoms that set the national scene abuzz in the late 1990s; it’s mostly been about diarrhea and loose stools.

Nevertheless, the researchers are urging parents away from putting their children on restrictive diets. “The findings from our study suggest that such treatments should not be provided indiscriminately to children with autism unless there is explicit evidence indicating the presence of a gastrointestinal disorder in a specific case,” the researchers wrote. “Given the already increased food selectivity among children with autism, as confirmed in our study, additional dietary restriction may place these children at risk for nutritional deficiencies.”

Manning-Courtney agreed. “For me, this study lends support to the recommendation I make to a lot of families that there is no evidence to support restricted diets,” she said. “They’re dangerous and risky. You have to think long and hard before you, as a parent, make that choice.”

The findings appear in the August issue of Pediatrics.