U. ROCHESTER (US)—A gluten-free, casein-free diet appears to have no impact on the behavior, sleep habits, or bowel patterns of children with autism, according to the most controlled diet study in autism to date.

“It would have been wonderful for children with autism and their families if we found that the gluten-free, casein-free diet could really help, but this small study didn’t show significant benefits,” says Susan Hyman, associate professor of pediatrics at the University of Rochester Medical Center.

“However, the study didn’t include children with significant gastrointestinal disease. It’s possible those children and other specific groups might see a benefit.”

Hyman will present the findings at the International Meeting for Autism Research May 22 in Philadelphia.

Researchers took on the difficult yet crucial task of ensuring participants received needed nutrients, as children on gluten-free, casein-free diets may eat inadequate amounts of vitamin D, calcium, iron, and high-quality protein. Hyman’s study enrolled 22 children, and 14 completed the intervention.

Unlike previous studies, they also controlled for other interventions, such as what type of behavioral treatments children received, to ensure all observed changes were due to dietary alterations. Past studies did not control for such factors.

Although no improvements were demonstrated, the researchers say that some subgroups of children, particularly those with significant gastrointestinal (GI) symptoms, might receive some benefit from dietary changes.

The researchers initiated the trial following widespread parent-reported benefits of a gluten-free and casein-free diet, which eliminates wheat, rye, barley, and milk proteins.

Parent observation has played an important role in earlier treatment discoveries in children with autism, such as melatonin’s benefits for sleep.

The families had to strictly adhere to a gluten-free and casein-free diet and participate in early intensive behavioral intervention throughout the study.

Children were screened for iron and vitamin D deficiency, milk, and wheat allergies and celiac disease.

After at least four weeks on the strict diet, the children were challenged with either gluten, casein, both, or placebo in randomized order. They were given a snack once weekly with either 20 grams of wheat flour, 23 grams of non-fat dried milk, both, or neither until every child received each snack three times.

The type of snack was given in randomized order and presented so that no one observing—including the family, child, research staff, and therapy team—knew what it contained.

The snacks were carefully engineered to look, taste and feel the same, which was an exercise in innovative cooking. In addition, the nutrition staff worked closely with the families to make a snack that met their child’s preferences. Casein was disguised in pudding, yogurt or smoothies and gluten in banana bread, brownies, or cookies depending on the child’s food preferences.

Parents, teachers, and a research assistant filled out standardized surveys about the child’s behavior the day before they received the snack, at two and 24 hours after the snack.

In addition, the parents kept a standard diary of food intake, sleep, and bowel habits. Social interaction and language were evaluated through videotaped scoring of a standardized play session with a research assistant.

Following the gluten and casein snacks, study participants had no change in attention, activity, sleep, or frequency or quality of bowel habits.

Children demonstrated a small increase in social language and interest in interaction after the challenges with gluten or casein on the Ritvo Freeman Real Life Rating Scale; however, it did not reach statistical significance. That means because of the small difference and the small number of participants in the study, the finding may be due to chance alone.

The study’s intention was to look at the effects of the removal of gluten and casein from the diet of children with autism (without celiac disease) and subsequent effect of challenges with these substances in a group of children getting early intensive behavioral intervention.

It was not designed to look at more restrictive diets or the effect of nutritional supplements on behavior.

“There are many possible effects of diet, including over- and under-nutrition, on behavior in children with ASD that need to be scientifically investigated so families can make informed decisions about the therapies they choose for their children,” Hyman says.

“This is really just the tip of the iceberg.”

More University of Rochester health news: www.urmc.rochester.edu/news/