By Roni Caryn Rabin, for The New York Times
Many parents of autistic children have put their children on strict gluten-free or dairy-free diets, convinced that gastrointestinal problems are an underlying cause of the disorder. But a new study suggests the complicated food regimens may not be warranted.
Researchers at the Mayo Clinic reviewed the medical records of over 100 autistic children over an 18-year period and compared them to more than 200 children without the disorder. The scientists found no differences in the overall frequency of gastrointestinal problems reported by the two groups, though the autistic children suffered more frequently from bouts of constipation and were more likely to be picky eaters who had difficulty gaining weight.
The study, published on Monday in the journal Pediatrics, is the first to look at the incidence of gastrointestinal problems in an autistic population, according to the paper’s first author, Dr. Samar H. Ibrahim, a pediatric gastroenterologist at the Mayo Clinic. She suggested that autistic children should only be put on restrictive wheat-free or dairy-free diets after having appropriate diagnostic tests done.
“There is actually no trial that has proven so far that a gluten-free and casein-free diet improves autism,” she said. “The diets are not easy to follow and can sometimes cause nutritional deficiencies.”
The study found that the vast majority of both autistic and non-autistic children suffered from bouts of common gastrointestinal problems like constipation, diarrhea, abdominal bloating, reflux or vomitin.g Feeding issues and picky eating were also common. Some 77 percent of autistic children and 72 percent of non-autistic children were affected by one or more of these complaints over the 18-year period.
About 34 percent of the autistic children were affected by constipation, compared to 17.6 percent of the comparison group, while 24.5 percent of the autistic children had feeding issues and were selective in their eating, compared with only 16 percent of the non-autistic group.
But very few of the autistic children had a specific diagnosis of a gastrointestinal disease. Only one autistic child had Crohn’s disease, and one had intestinal disaccharidase deficiency and lacked enzymes necessary to digest certain carbohydrates. None suffered from celiac disease, which some reports have linked to autism.
Two of the non-autistic children in the comparison group suffered from lactose intolerance, and one had a milk allergy.
Dr. Ibrahim suggested that the loss of appetite and difficulty gaining weight in autistic children may be related to the use of stimulant medications, which are often prescribed for the condition, and that the constipation may be due to children not consuming enough fiber or drinking enough water.