Sept. 28, 2011 (San Diego) -- Up to half of children with autism are placed on special diets by their parents to improve symptoms, despite conflicting evidence that they work.
Now, a small new study of the popular gluten-free/casein-free diet, or GFCF diet, suggests it does not work, says Patricia Stewart, RD, PhD, of the University of Rochester. She presented the findings here at the American Dietetic Association's Food Conference Expo in San Diego.
Stewart enrolled 22 children, ages 30 to 54 months, to go on the GFCF diet. The research was funded by the National Institute of Mental Health under the STAART (Studies to Advance Autism Research and Treatment) Network.
Only 14 children were able to maintain the strict diet for the four-week minimum required for the study. It requires that all foods containing gluten and casein be removed from the diet. Gluten is a protein found in foods made from wheat, barley, and rye. Casein is a protein found in milk.
Six weeks after the study began, Stewart started the food challenges with the children. These included portions of wheat flour, milk, both, or placebo. She and others observed their behaviors. They found:
- No effect on sleep
- No difference in stool frequency or consistency
- No difference in ratings of attention or activity by parents, teachers, or researchers
- No noticeable differences in social interactions, language, or movement behaviors
"Nevertheless, parents will continue to try many of these diets based on what is out there [about them working]," says Stewart, director of the Clinical Research Center at the University of Rochester School of Medicine.
And despite conflicting evidence that special diets for autism work, she says, parents who decide to try it deserve the support of their health care providers. Few of the diets have been tested thoroughly and scientifically.
Study of Nutrients in Children With Autism
Researchers also found that children with autism lack some important nutrients but have sufficient intakes of others whether they are on or off a special diet.
Children with autism often eat only a few, favorite foods, or are otherwise picky about what they eat. Experts worry about their nutritional status.
So in another new study, Stewart analyzed the food records of 252 children with autism, hoping to find out if their nutritional status is inadequate.
Although she has yet to complete the analysis of all the children, so far she found children with autism lack some nutrients but not others.
More children with ASD got enough vitamin K and E compared to general population.
While many parents give supplements to their children with autism automatically, she suggests health care providers should be asked about it. They should evaluate whether the children need extra supplements or if they get enough nutrients from diet.
In a third study presented at the meeting, Kent State University researchers evaluated the nutritional status of children with autism while on a GFCF diet. They looked at the diets of 31 children, ages 6 to 11. Some were on a GFCF and some ate a regular diet. They looked at three-day food records. Those on GFCF diets had lower intakes of vitamins B1, B2, B12, and D, calcium, phosphorus, and selenium than those on the regular diet.
Children With Autism and Gut Problems
There may be a subgroup of children with autism spectrum disorder who do better with dietary intervention, says Timothy Buie, MD, an associate in pediatrics at the Massachusetts General Hospital, who also spoke at the meeting. He often sees children with autism who have gastrointestinal (GI) problems, such as acid reflux, in which stomach contents travel back up the esophagus.
Buie showed videos of three children with autism. They had repetitive behaviors such as repeated flailing. After evaluation, he found all three had acid reflux. But none had clear symptoms of a GI problem, he says.
''Kids with autism who present with GI issues warrant a through evaluation," he says. "But I think it's not happening." As Stewart said, parents should involve health care providers to address such issues.
Parents who suspect a GI problem with their child with autism should ask for the last appointment of the day, he says, or the last appointment before lunch. That will help ensure enough time is given, Buie says.
Buie reports project support on a diet study from Nutricia Advanced Medical Nutrition, project support from Autism Speaks and previous support from Newman's Own Foundation.
These studies were presented at a medical conference. The findings should be considered preliminary as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.