Despite parents who believe otherwise, gastrointestinal (GI) problems do not cause autism in children. In addition, restrictive food regimens used by these parents don’t improve autism and may even create nutritional deficiencies, according to a new study published in the journal Pediatrics and reported on by The New York Times.

Mayo Clinic researchers studied the incidence of GI problems in more than 100 autistic children during an 18-year period. They compared these children’s medical records with those of more than 200 non-autistic children.

Researchers found that GI problems, such as constipation, diarrhea, abdominal bloating reflux or vomiting, were common to the majority of both groups of children studied, those with and without autism.

Scientists also found that although both groups of kids were picky eaters and had feeding issues, more autistic children exhibited these tendencies. More autistic youngsters also suffered from constipation.

As a result of the findings, Mayo Clinic pediatric gastroenterologist Samar H. Ibrahim, MBChB, the study’s first author, recommended that autistic children not be placed on restrictive diets unless they undergo proper diagnostic testing.

“There is actually no trial that has proven so far that a gluten-free [wheat-free] and casein-free [dairy-free] diet improves autism,” Ibrahim said, citing two popular restrictive diets parents of autistic children use.

Ibrahim indicated that autistic children’s diet-related problems, such as appetite loss and difficulty gaining weight, may result from the stimulant medications prescribed for autism. Their constipation, Ibrahim suggested, may be because they do not eat enough fiber or drink sufficient water.

Read more about autism here.