Gastrointestinal Symptoms and Autism

GIWhat are gastrointestinal symptoms?

When people talk about gastrointestinal (GI) symptoms and autism they could be talking about a variety of different things including constipation, diarrhea, abdominal bloating/discomfort/irritability, gastroesophageal reflux/vomiting, or food selectivity/feeding issues.  Sometimes they may be referring to GI diseases like Crohn’s disease (an inflammatory bowel disease) or Celiac disease (an immune reaction to eating gluten).

Do children with ASD have more gastrointestinal issues than typically developing children?

Most evidence indicates that children with autism are no more likely then the general population to have GI diseases and are specifically no more likely to have ciliacs.  There is some evidence that children with autism do have higher rates of food selectivity/feeding issues and constipation.  Even though children with autism may not be more likely then typically developing children to experience tummy trouble, they still experience GI issues frequently (as many as 24% of children with ASD).  Diarrhea is the most common issue for children with ASD.  Having said that, GI issues among children with ASD may be under reported because parents or doctors may miss understand why the child is upset or uncomfortable.

GI difficulties may be particularly difficult for children with ASD.  They may not be able to communicate that they are uncomfortable or in pain.  The lack of regular bowel movements may cause disruption to important routines which may cause a child additional distress.

What causes children with ASD to have gastrointestinal issues?

It’s not clear that the causes of GI issues in children with ASD is different from typically developing children.  There are many things that  can cause GI issues in children such as anxiety, food allergies, food sensitivities, food born illnesses, and GI diseases.  There are some issues that are particularly important for children with ASD.  If a child with ASD has a very selective diet they may be missing out on vital nutrients that could lead to GI issues.  If a child with ASD is presenting with behavioral issues, GI issues, especially pain, maybe an underlying cause even if the behavioral issues appear to be unrelated to food.

There are a couple theories that are related to GI issues and ASD that don’t have much support.  The first is a theory of abnormal gastrointestinal permeability often called “leaky gut” theory.  This theory suggest that a “leaky gut” actually causes autism and autism symptoms and that gluten and casein should be completely avoided.  The research on this theory has methodological problems (like using very small sample sizes or only looking at children with ASD and a GI disease).  There’s another theory that there’s a specific GI disease only found in children with ASD called autistic enterocolitis, however the same symptoms are found in typically developing children.

Can a special diet help my child?

If your child has a food allergy or intolerance eliminating that food item can help reduce physical discomfort that maybe contributing to additional distress and even causing behavioral problems.  Similarly, if your child has a selective diet and is failing to get specific nutrients, helping your child to expand their diet could reduce GI issues.  Before making diet decisions, it’s important to talk to a doctor.  Any individual with ASD who presents with GI symptoms should have a full evaluation preferably by a GI specialist.

No diet can cure a child of autism.  A diet cannot treat the underlying causes of autism.  If you’re child has GI issues than a diet maybe a treatment option for those issues.  GI issues may be a cause of problematic behavior and therefore a diet may reduce problematic behavior.

Where can I get more information?

The book Special Diets for Special Kids is a great resource for learning how to implement a special diet.  Can’t Eat, Won’t Eat is a book the focuses on overcoming selective eating.  Web MD has a nice article explaining the Gluten Free-Casein free diet.  Autism Speaks has a regular series featuring a GI doctor with experience with autism.


Ibrahim, S. H., Voigt, R. G., Katusic, S. K., Weaver, A. L., & Barbaresi, W. J. (2009). Incidence of gastrointestinal symptoms in children with autism: a population-based study. Pediatrics, 124(2), 680-686.

Molloy, C. A., & Manning-Courtney, P. (2003). Prevalence of chronic gastrointestinal symptoms in children with autism and autistic spectrum disorders. Autism, 7(2), 165-171.

White, J. F. (2003). Intestinal pathophysiology in autism. Experimental Biology and Medicine, 228(6), 639-649.


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