Making Connections
Scientists find a gut-brain link in autism
BY Katherina Dehaas
Ryan, 5, was diagnosed with autism when he was two-and-a-half years old. When he was 4, his mother, Lisa Foxcroft, searched for treatment options. A naturopath suggested a gluten-free diary-free diet which is believed to help control the symptoms of autism.
Foxcroft said she tried it, "pardon the expression - half-assed." Ryan wouldn't drink the milk. He wasn't crazy about the rice-bread either. But did she notice any improvements in his behaviour?
"He's a little calmer in some instances. But what's that attributed to? It's hard to pinpoint whether that's the diet (or not)."
"He's a little calmer in some instances. But what's that attributed to? It's hard to pinpoint whether that's the diet (or not)."
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Who is to say what caused the improvement - the diet, the therapy, or just maturation? Well - no one. At least not scientifically speaking. There is no hard evidence to prove that a gluten-free and dairy-free diet has any significant effect on autism.
Sure there's plenty of anecdotal evidence, including an entire book devoted to the topic written by Playboy-bunny-turned-mommy Jenny McCarthy, but there are no scientific studies proving the diet is effective.
Read more about Celebrity Endorsement and the "Autism Diet"
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Derrick MacFabe
SOURCE: DERRICK MACFABE
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So where are these rumours coming from and what, if any, is the link between diet and autism?
Dr. Derrick MacFabe, director of the Kilee Patchell-Evans Autism Research Group, is an authority on the subject. And he should be. Last fall, his interdisciplinary team, based in London, Ont. found a probable link between diet and autism. But it's not what you think, and despite some reports linked to his research, MacFabe does not advocate the diet nor does he recommend it. And for the record, he's never even met Jenny McCarthy.
According to MacFabe, parents and the autism research community noticed that children with autism often experienced digestive problems including diarrhea, constipation, and cravings for carbohydrate-rich foods. For example, there were "kids getting up in the middle of the night and eating the entire inside of a loaf of bread. And then their behaviours got worse and their digestive system ... got worse," said MacFabe.
"Historically families were saying 'hey, when my kid only eats this, their behaviours change', and so simple parenting says to limit these foods. And some people noticed some of the gastro-intestinal system problems and changed. Some reported improved behaviour."
This is the kind of anecdotal evidence that exists in support of the gluten-free and dairy-free diet. But anecdotes are not proof and MacFabe's team were in search of science, not here-say.
"So there are talks out there about special diets - we're not advocating this. But we are saying that something might be common to effects that we see in the diet, in the increase of the disease, on the GI symptoms," he added.
"What I wondered is - is there something common to these things going on in the diet, in the digestive system, in the brain, in the immune system of some children that would kind of tie these things together?" he asked.
It's like the blind man and the elephant - you're trying to see different aspects of this and if there is something that could fit," he said.
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It was through this line of questioning that his current research was born.
The Kilee Patchell-Evans Autism Research Group is focused on the study of autism from a variety of angles. The group includes doctors, neuroscientists, and psychologists working to shed some light on the disease and its related disorders.
And the discovery this past fall has been very encouraging.
They set out to find a link between compounds produced by bacteria in the digestive system, and the brain. They were able to identify a compound called propionic acid, a short-chain fatty acid, and one that, when administered to the brains of rats in the laboratory tests, elicited behaviours not unlike those displayed by children with autism.
But how does this all work?
"...We are not alone," said MacFabe, referring to the millions of bacteria at home in our digestive systems. He says that we have normal bugs in our digestive systems right from birth - and we need them.
"If you don't have any of these good bacteria you don't have normal development of your immune system, your digestive system and your brain," he said.
But there is a balance of good bugs and bad bugs and problems can arise when that balance is disrupted. It is possible that some good bugs are being wiped out by the overuse of antibiotics in the population.
"What we found are these particular bugs. The 'good' bugs could be reduced with the over-use of antibiotics and these certain antibiotic-resistant bugs in the digestive system could be overgrowing," he explained.
But what do bugs have to do with autism?
MacFabe, a whiz with analogies, explained using an example we can all relate to.
"Just like if you make beer or wine you have bacteria, or yeast, and you give them carbohydrates - sugars - and then you get alcohol, these little bugs make something similar to it which we call fatty-acids," he said.
"So when you feed yourself you feed the bugs and these bugs are producing something. In addition to alcohol having a lot of effects on the brain and behaviour, I wondered if these bacteria could be producing compounds that would have interesting effects on the brain and the immune system,".
One such compound has been identified as propionic acid or APA for short, said MacFabe. And further research has shown that when this compound is administered to rats it has a profound effect on their brains, and behaviour, just as they suspected.
But nothing is final. There is still further research to be done. Yet identifying the propionic acid was encouraging.
"At least we have a compound -- a plausible link," he said. "There's maybe something common to diet, digestive system function, immune system, brain and behaviour that can link this. That's a good place to start," he says.
And any progress in the field of autism research is good news - especially for people like Foxcroft and her son Ryan.