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Can gluten/casein-free diet trigger tantrums in someone with autism?

“Can switching someone with autism to a gluten-free casein-free diet cause behavioral problems – in this case, tantrums – at the beginning? How will we know if it’s helping?”

This week’s “Food for Thought” answer is by pediatric gastroenterologist Timothy Buie. Dr. Buie is the director of gastrointestinal and nutritional services at Massachusetts General Hospital’s Lurie Center for Autism, a member of the Autism Speaks Autism Treatment Network (ATN).

Editor’s note: The following information is not meant to diagnose or treat and should not take the place of personal consultation, as appropriate, with a qualified healthcare professional and/or behavioral therapist.

Thanks for your question. Let me preface my answer by noting that studies have failed to show that special diets – including the gluten-free, casein-free (GFCF) diet – improve autism symptoms.

That said, some – perhaps many – children with autism have food allergies and food intolerances. There’s also a growing amount of medical research suggesting that food allergies are particularly common among children with autism. In our own work, we frequently see lactose, or milk, intolerance in children who have autism and gastrointestinal (GI) symptoms serious enough to warrant an endoscopy.

GFCF diets address two of the most common food allergies and sensitivities in the general population. Casein is a protein found in milk, and gluten is found in wheat, rye and barley. Celiac disease, though relatively rare, involves a very serious reaction to gluten.

Autism and resistance to change
Now to answer your question more directly. Yes, there are several reasons why initiating a GFCF diet may prompt challenging behaviors such as tantrums in someone who has autism.

First, many families who decide to adopt a GFCF diet do so abruptly. An abrupt change may be appropriate if a food is causing acute reactions like rashes, vomiting, wheezing or even a life-threatening allergic reaction (anaphylaxis).

But as you can imagine, abrupt changes don’t generally go over well with people who have autism. By its nature, autism involves a strong need for sameness. And many people with autism are particularly averse to changes in their diet. For example, they may become upset at even a small change in, say, their regular morning cereal. This can include even subtle texture or taste differences between brands.

The reaction to the unwanted change can include tantrums or other challenging behaviors – particularly if the person cannot communicate well otherwise.

So in the absence of an acute food allergy or intolerance, I recommend that dietary changes be made gradually and with sensitivity to adjustment and acceptance of new products.

Changes in the microbiome
Another possibility is that the change in diet produced a change in the balance of digestive microorganisms in the person’s gut. We call this community of internal organisms the microbiome. Even when this change is beneficial over the long term, it can cause a brief initial period of GI distress involving a change in stools (constipation or diarrhea) and gassiness.

I suspect this may be what you are seeing. Fortunately, the distressing symptoms tend to resolve within a few days as the microbiome re-balances.

New foods producing sensitivities
Yet another possibility is that the person has developed a sensitivity to one or more of the new foods introduced with the GFCF diet. We often see this when a mainstay food is withdrawn and consumption of the replacement foods increases. For example, children who no longer eat wheat (gluten) products will typically eat more foods containing rice and/or corn. The new foods may produce a change in stool (constipation or diarrhea), increased bloat and gassiness or other GI symptoms. This may resolve over time, or it may require identification and elimination of the offending food.

Other popular diets with similar effects
It also bears mentioning that discomfort and behavioral issues can arise with any significant diet change – not just a change to the GFCF diet. Other diets currently popular in the autism community include the food elimination diet, the specific carbohydrate diet, GAPS (Gut and Psychology Syndrome), FODMAPS (Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols) and the ketogenic diet.

Enlisting professional guidance
I highly recommend the guidance of a nutritionist when attempting a major diet change – particularly one involving a child who has autism. The dietician can help ensure that the child’s nutritional needs continue to be met. This is particularly important with regards to calcium and vitamin D as well as maintaining adequate protein.

Assessing benefits
It’s also important to set clear expectations for what constitutes a “good response” to a dietary change. Some obvious benefits includes improved stools (neither painfully hard nor too loose), improved sleep, disappearance of skin rashes, etc.

One possible benefit of a GFCF diet involves removing an allergy trigger or a food that the person has trouble digesting. If this is the case, you’ll usually see an improvement in discomfort and/or behavior within a week or two. Improvements may continue over time, but usually you’ll see some indication of benefit fairly quickly.

Admittedly, the gradual adoption of a new diet means it will take longer to assess any benefits.

Even when you see a benefit from a diet change, it doesn’t necessarily mean that the new diet must be permanent. With food allergies, for example, eliminating the food for a period of time may produce a decrease or even elimination of the earlier sensitivity. However, reintroducing a food that has provoked an allergic reaction in the past should be done with careful medical supervision. Some diets do need to be continued, but with time the occasional “indulgence” may be allowed.  

I hope this information is helpful. Please let us know how you are doing with a comment below or by writing us again at

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The Autism Speaks blog features opinions from people throughout the autism community. Each blog represents the point of view of the author and does not necessarily reflect Autism Speaks' beliefs or point of view.