Scientists make gut-brain connection to autism
Last Updated: Thursday, September 27, 2007 | 5:29 PM ET
CBC News

Compounds produced in the digestive system have been linked to
autistic-type behaviour in laboratory settings, potentially
demonstrating that what autistic children eat can alter their brain
function, say scientists from the University of Western Ontario.

They announced their findings Thursday in Ottawa.

Scientists are learning that the brain and body can influence each
other, says a Harvard researcher.

(CBC) UWO researchers investigated the "gut-brain" connection after
many parents of autistic children reported significant improvements in
the behaviour of their autistic children when they modified their
diet, eliminating dairy and wheat products, Dr. Derrick MacFabe, the
director of a research group at UWO in London, Ont., told CBC News
Thursday.

Researchers were particularly interested in one dietary characteristic
the autistic children seemed to exhibit, he said.

"Certainly, a lot of these children had peculiar cravings for high-
carbohydrate foods that caused their behaviours," he said.

"We were interested in finding a link between certain compounds that
are produced by bacteria in the digestive system -- particularly those
occurring with early childhood infections."

The bacteria produce propionic acid, a short chain fatty acid, which
in addition to existing in the gut, is commonly found in bread and
dairy products, MacFabe said.

To test their hypothesis that diet plays a part in generating autistic
behaviour, UWO scientists administered the compound to rats' brains.

"They immediately engaged in bouts of repetitive behaviour,
hyperactivity and impaired social behaviours which had close
similarity to what parents are seeing with autism," MacFabe said.

When the rats' brains were examined later, they were found to have
inflammatory processes similar to those in the brains of autistic
children, he said.

"We found, looking at the rats' brains under the microscope, changes
that looked a lot like what's occurred from autopsy cases of patients
who had autism."

It's remarkable that a simple compound like propionic acid would have
such a dramatic effect on "normal" animals, he said.

MacFabe said his research team, and scientists at Queen's University
in Kingston, Ont., and Harvard University, are now conducting
screening studies looking at effects of dietary changes in the general
population.

New way of approaching autism

Dr. Martha Herbert, assistant professor in neurology at Harvard
Medical School, told CBC News that the study opens up a new way of
thinking about the disorder.

"Now we're learning that the brain and body can influence each other,"
she said.

Autistic children are increasingly being seen as "oversensitized,"
meaning "things may bother them that don't bother other people," she
said. "We need to pay attention to this."

Treating a child's health should be the first step in addressing
autism, Herbert said, rather than solely focusing on behavioural
therapy, currently a mainline approach.

"Behaviour therapy is certainly important. But the child's health
controls the bandwidth that the child has for being able to benefit
from behavioural therapy. If a child is sick, they won't be able to
focus."

Parents should watch their children closely to determine what foods
trigger reactions and to consider removing those triggers, she said.

Herbert strongly advocates a balanced diet, consisting of all food
groups, not just "bread and cheese."

"If you have foods that child is sensitive to in their immune system,
that can set up processes that can impact brain function, and it can
do so in a negative way. And if you remove those foods, that negative
impact can stop."

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