Can food allergies aggravate autism symptoms?


This week’s Food for Thought answer is by nutritionist Kelly Barnhill, director of clinical care at the Johnson Center for Child Health & Development, in Austin, Texas.

“Can food allergies produce inflammation that causes bad days for someone with autism?”

Thank you for your great question. Food allergies can, in fact, produce inflammation throughout the body. In our clinic, we see many children with food-related issues, including allergies and intolerances.  I think it’s critical to know the difference between these two food responses to understand the resulting issues and how to handle them.  

Classic food allergies
Food allergies result from a strong immune response to a food, and the resulting inflammation can involve multiple body systems. With classic food allergies, this immune response involves a particular antibody, IgE (immunoglobulin type E). 

Typically, this results in a cascade of immune responses that include a release of histamine and other inflammatory molecules. The result: those troublesome allergy symptoms – runny eyes and nose, sneezing, coughing and sometimes worse. We call an extreme, whole-body response “anaphylaxis.” The most severe form of food allergy, anaphylaxis is life-threatening and must be treated quickly.   

Clearly such symptoms can cause a bad day for anyone. This can be particularly true of a child or adult living with autism – who may not be able to communicate or fully understand or explain his or her discomfort. 

Allergy testing
Many families enter our clinic believing their child is allergic to a food because their child has negative reactions to it. These responses can be physical – for example, stomach pain, lethargy, or hyperactivity. Or they can be behavioral – for example, acting out irritation or retreating into repetitive behaviors. Parents often list milk, gluten, soy, corn and egg proteins as the primary offenders. 

Typically, we work with allergists and immunologists to determine whether true food allergies are involved. This can involve skin testing and blood work. Many times these tests indicate that children do, in fact, have true allergy responses. Other times, the tests come back “negative” for allergies. 

Delayed inflammation and autism symptoms
There’s another inflammatory food response that we’re seeing more and more of in our clinic: eosinophilic esophagitis. This is not a classic food allergy. Rather it involves a mixed IgE and non-IgE response. The resulting inflammation produces changes in the cells lining the esophagus (the part of the throat leading to the stomach).  Avoiding the offending foods allows the esophagus to heal, along with the rest of the GI tract.   

This type of non-IgE mediated allergy involves a delayed response to a particular allergy-provoking substance. We call these substances “allergens.” The reaction stops when the allergen is avoided.  Allergists, immunologists, and other specialists must use a number of different tests to detect these issues.

Researchers continue to study non-IgE antibody mediated allergies and autism symptoms. Some interesting and potentially helpful findings are emerging.  These findings support what we hear from families: That this type of delayed inflammatory response can affect sleep, focus and attention. It can also worsen irritability, hyperactivity and repetitive behaviors in children with autism.

A clinician may order testing to look for any delayed food responses if there are concerning symptoms that vary from physical to behavioral that have no other biological or behavioral explanation.

Food intolerances
Food intolerances are another issue entirely. Typically, they’re associated with a non-immune response to a component of a food. A classic example is the inability to digest lactose (milk sugar). This can certainly cause GI distress including stomach pain, bloating and diarrhea.

When a parent sees a child responding negatively to a food, we trust that observation. We attempt to track, document, and understand these responses on a patient-by-patient basis by gathering as much information as possible. This can include questions about sleep, behavior and learning, as well as observations provided by teachers and other caregivers.

Food, inflammation and bad days
So to answer your question, yes, food allergies and intolerances can certainly cause a child to feel uncomfortable and act out. Clearly, inflammation and GI distress in any form doesn’t feel good for anyone. 

I believe that any child can sleep better, behave better, learn better and perform better when he or she feels better.  When fighting allergies or experiencing food intolerances, a child’s body is compromised. That can certainly make some behaviors worse and cause what parents call “bad days.” 

By evaluating and treating potential food responses through diet, nutrition and medical support, we can work together to allow a child to heal and thrive. 

Need more help with issues around food, eating behaviors or special diets? Send your questions to:


Also see the Autism Speaks ATN/AIR-P Guide to Exploring Feeding Behavior in Autism. Research suggests that more than half of individuals with an autism struggle with food issues that can affect health and emotional wellbeing. This tool kit provides guidance from experts in the Autism Speaks Autism Treatment Network.