HOUSTON --Parents of autistic children have long suspected that what their children eat affects their behavior. Now University of Texas at Houston researchers are taking a first look at whether their suspicions are true.

“We want to know if gluten and milk... have any relation to changes in behavior," explained Dr. Fernando Navarro with UT Houston.

Autistic children often experience an intestinal problem known as leaky gut. Researchers wonder if it's the culprit behind their irritation, another common trait.

"We would like to know if there is any relation between what happens in the stomach and what is happening in the brain," Dr. Navarro said.

Paul Tebo is 8 years old and he’s autistic.

He's taking part in the landmark study.

Since going without dairy products and wheat, Paul's mom Wendy has already seen changes -- along with a precious first.

“He said, 'Mommy, I love you so good,'" Wendy Tebo said as she choked back tears.

If dairy and wheat are part of the problem, the Tebos will be happy to scratch them off the menu.

That means Paul would have to give up some of his favorite foods.

“The chicken nuggets we can’t do right now because it has the breading," Wendy Tebo said.