An autism support group has called for more research and more help treating the gastrointestinal issues of autistic children after an expert panel published a report saying there is currently no evidence that special diets help autistic behavior.
For years, parent support networks and celebrity activists have endorsed restrictive diets to combat the so-called "leaky gut" symptoms and behavioral problems of children with autism.
But the expert panel came to a consensus statement that "available research data do not support the use of a casein-free diet, a gluten-free diet, or combined gluten-free, casein-free (GFCF) diet as a primary treatment for individuals with ASD's (autism spectrum disorders)."
The statement on so-called autism diets was one part of a larger report on how doctors should approach gastrointestinal issues in children with autism.
The report, published Monday in the journal Pediatrics, echoed some parents' claims that gastrointestinal issues are linked to autism-like behaviors. Without a way to communicate their pain, these experts suggest children exhibit other behavior such as emotional outbursts or repetitive behavior.
But the panel of 27 specialists agreed that "problem behavior in patients with ASDs may be the primary or sole symptom of the underlying medical condition, including some gastrointestinal disorders."
"I think a lot of the time these kids are misbehaving because they don't feel well," said Rebecca Estepp, a mother of a boy with autism and national policy manager for Talk About Curing Autism. Estepp believes her son and others with autism and gastrointestinal issues may be acting out in part because they unable to communicate their pain.
An estimates 15,000 families participate in the support and activist group TACA. "The overwhelming majority of these families do this diet," said Estepp. "Study them," she urged.
But until studies prove or disprove the merits of casein-free and gluten-free diets, the experts recommended adapting more traditional treatments for gastrointestinal problems in children with autism.
"Probably 90 percent of parents of children with autism try dietary intervention," said Dr. Fred Volkmar, director of the Child Study Center at Yale University.
"The sad reality of it is that with any complementary alternative treatment -- there is no evidence. It's what makes it [a] complimentary alternative treatment," said Volkmar.
Dr. Timothy Buie of Harvard Medical School said published studies suggest only around 30 percent to 50 percent of parents of children with autism try restrictive diets. Still, he sensed the peer pressure to try a diet was intense and did not recommend parents try a diet on their own.
"I am very willing to walk the pathway of dietary intervention with a family," said Buie, who was lead author of the report. But "I want to have the most information."
Volkmar said his patients often try the restrictive diets after hearing anecdotes from other parents, which is not proof enough for scientists and doctors. He also thinks parents are keen to pick up on diets as a form of treatment because a common characteristic in children with autism is finicky eating.
Estepp said she first started wondering about her son's diet for those very reasons.
"I put my son on this diet nine years ago, and there was no evidence but the evidence of my son's constant diarrhea, constant indigestion," said Estepp. "He also avoided milk. I kept thinking, what 2-year-old pushes away the milk cup?"
Estepp said her son's health improved after she put him on a restrictive diet. It didn't cure his autism, but she thinks his better health led to better behavior.
But parents who want hard scientific evidence before trying the casein-free, gluten-free diets may have to wait a while.
"For many researchers, this would be a lower priority. The problem is there's limited federal dollars, it's an amazing amount of work to get these [treatment] studies done," said Volkmar.
The vast spectrum of behaviors and medical issues within autism only compounds the problem. Autism ranges from severe behavioral and communication problems to cases of highly-functioning but somewhat socially challenged people. Since gastrointestinal issues may be more common in some areas of the autism spectrum but not in others, doctors say lumping children into one autism category to study diet may confuse the results.
"Studying them [patients] in large groups of people who are heterogeneous -- very different from one another -- is not the best way to learn what is going on with these diets," said Dr. Martha Herbert of Massachusetts General Hospital in Boston. "You will wash out any effect in a subgroup by blurring them in with others who have different problems."
The panelists contributing to Monday's report could only find one double-blind placebo controlled study on the behavioral effects of a casein-free/gluten-free diet. The study found the diet had no effect on autism symptoms, but it included only 15 children and lasted for only 12 weeks.
Still, many researchers have found links between behavioral disorders and gastrointestinal problems.
"There is a higher reported rate of GI (gastrointestinal) problems in children with autistic spectrum disorders compared with normal children and with children with other developmental disabilities," said Dr. Shlomo Shinnar, of the Montefiore Medical Center in The Bronx, N.Y. "This has been reported in multiple case control studies."
But a higher rate among children with autism doesn't mean autism caused the intestinal problems or vice versa, Shinnar said.
"At the present time, the higher rate of GI symptoms remains an interesting finding that is worthy of further research but does not provide us with either a cause or a treatment for autism," he said.
Dr. Arthur Beaudet, who contributed to the published statements, said he believes genetic studies may one day lead to better research of gastrointestinal problems in children with autism.
For instance, children with autism symptoms caused by one genetic mutation may be more likely to develop gastrointestinal issues than children who have a different genetic mutation -- or none at all.
Beaudet said current research has already pinpointed subgroups of people with autism who have a specific mutation and distinct behavior, such as the estimated 1 percent of people with autism who have the mutation known as "16p11.2"
"There's a very broad spectrum of autism from very severe handicaps to very mild handicaps… we have to break these down to the smallest extent possible," said Beaudet. With focused groups within the autism spectrum, studies may be more focused and effective.
Although studies on the diets are lacking, Estepp said she was "ecstatic" that doctors are making recommendations on how to approach treating stomach problems in children with autism.
"That makes all the difference in the world to someone who cannot speak," said Estepp. "I wished this had happened 10 years ago when my child was diagnosed."