Researchers at the University of Rochester Medical Center in New York found that eliminating two things from children's diets -- gluten, which is found in wheat, and casein, found in milk products -- didn't affect how they behaved or slept, nor did it change their digestive habits.

The study authors noted that their research is more rigorous than previous ones.

"It would have been wonderful for children with autism and their families" if the non-gluten and non-casein diet worked, lead investigator Dr. Susan Hyman, an associate professor of pediatrics at Golisano Children's Hospital at the University of Rochester, stated in a university news release. "But this small study didn't show significant benefits."

Hyman did caution that "the study didn't include children with significant gastrointestinal disease. It's possible those children and other specific groups might see a benefit."

The investigators enrolled 22 children aged 2.5 to 5.5 years, and 14 completed the 18-week intervention in which their families eliminated wheat, rye, barley and milk proteins from their diets.

After at least four weeks, the researchers "challenged" the children with food products that included gluten, casein, both or a placebo.

The study authors found that the children's attention, activity, sleep and bowel patterns didn't change after they consumed the products in the food challenge.

"This is really just the tip of the iceberg. There are many possible effects of diet including over- and under-nutrition on behavior in children with [autism] that need to be scientifically investigated so families can make informed decisions about the therapies they choose for their children," Hyman said.

The findings are scheduled to be presented Saturday at the International Meeting for Autism Research in Philadelphia.