There are many health practitioners in the autism treatment communities promoting the Gluten Casein Free Diet (GCFD) as therapy for children with autism. GCFD as a therapy is based on the theory that gluten and casein can cause injury to the bowel. The theory goes as follow:

Gluten/Casein-induced bowel injury renders the intestine “leaky” thereby allowing toxins to enter the bloodstream, and then the brain. These toxins then cause injury to the brain resulting in autistic behaviors.

I have a hard time understanding and accepting this “Leaky-Gut” theory, especially given that it has not been supported by the scientific studies carried out to date. Furthermore, the medical literature looking at GCFD has yet to convincingly demonstrate any evidence of a beneficial effect from the diet.

So how does one make practical sense of this information? Well,  to start with, consider this saying in science that “the absence of evidence is not evidence of absence.” In other words, just because there is an absence of evidence to support this “leaky gut” theory, it is not evidence that the theory is false. When I encounter cases where parents are convinced that GCFD helped their child, I remind myself that it is entirely possible that the “leaky gut” theory’s scientific support has simply not yet been discovered.  That said, I most certainly wouldn’t make a recommendation based on a theory lacking any scientific support. So it’s easy enough for me to say that I do not actively recommend GCFD as an evidence-based treatment for Autism. But a more interesting and nuanced question, something I struggle with regularly, is whether I should actively recommend against the GCFD as treatment for autism.

At the infant, child, and adolescent nutrition (ICAN) clinic at North York General Hospital in Toronto, I see a number of autism patients with nutritional problems. Their parents often ask me for my opinion on GCFD. The most typical scenario is the parents have already started the diet, aren’t entirely sure whether or not it made a difference, and want to know if I think they should continue. It’s a bit tricky to answer these sorts of questions because I face conflicting guiding principles in trying to come up with a helpful response.

On the one hand, it’s important for physicians to primum non nocere, or “first, do no harm”. Prominent in the Hippocratic Oath, this is one of the fundamental ethical principles governing the professional conduct of physicians. If, by initiating GCFD, a given parent actually improved their child’s health, then by recommending against this intervention, I risk causing harm to that child.

On the other hand, there are real risks associated with GCFD, especially among children with autism who have particularly picky eating habits. Our own research (in preparation for publication) at the ICAN clinic shows that ironically, the two favourite food groups among our patients with autism are grains and dairy. Since gluten is so commonly found in grain products, and casein in dairy products, one can see that removing the grain and/or dairy food groups from a child’s diet can lead to one or more nutritional deficiencies resulting in a serious risk of medical harm.

I respect parents’ rights to make medical decisions on behalf of their children. In that context, I hope to support parents in doing so while at the same time promoting the healthiest options for their children. In that spirit, when a parent chooses to trial the GCFD for their child, the best way for me to support this family would be not to judge or criticize the decision, but to work out a nutritional plan that respects the GCFD principles while at the same time ensures adequate and balanced nutrition. Sometimes this can be realistically achieved. But unfortunately, there are children whose palates are so restricted that any attempt to restrict gluten and/or casein results in true malnutrition. It is in these cases that the GCFD is not appropriate.

For some helpful information about gluten allergy and intolerence, check out this Q&A by Dr. Joseph Murray, a gastroenterologist and professor of medicine at the Mayo Clinic in Rochester, Minnesota. He is a senior associate editor of the American Journal of Gastroenterology.

For parents who wish to try GCFD for their child, I recommend first discussing this decision with your pediatrician and a pediatric dietician who has expertise in autism and nutrition. I also recommend that you first try introducing the gluten/casein-free equivalent products to ensure your child will actually accept them before starting to eliminate any food items. For example, suppose a particular child’s only source of grains is sliced bread. Before eliminating gluten from her diet, introduce gluten-free breads first to ensure that she will accept them as an alternative.  If she refuses to eat the gluten-free breads, it becomes very difficult to ensure adequate grain intake after removing gluten from the diet. If your child readily takes the alternate replacement items, there is little risk to trying GCFD.  Once the gluten/casein is succesfully eliminated, periodically monitor your child’s behavior as objectively as possible to determine whether the dietary intervention has helped.  It may be worthwhile asking others to observe as well; ideally they would be blinded (i.e. unaware that you made the dietary intervention). Compare their observations with yours.  If you believe things have improved and the child’s diet is balanced, then it makes sense to keep going.  If not, then go back to gluten and casein.  There’s no point continuing in the absence of any clear benefit.

Please consider sharing your experiences with and perspectives on GCFD below.

If you live in Toronto and would like nutrition support for your child, feel free to learn more about the Kindercare Pediatric’s clinical nutrition programs.