Food Allergies & Digestive Problems in ASD Individuals

  • Josh Donaldson, ND

    Most of you are aware of the importance of diet as well as the incidence of allergies in autism spectrum disorders (ASD).  It is well documented that individuals who suffer from food allergies often have concurrent neurological, gastrointestinal and/or immune disorders.  Parents and clinicians agree that dietary intervention can compliment behavioral and speech therapies to benefit individuals with autism/ASD.  As important as that is, it is imperative to dig a little deeper to find out exactly why it is beneficial to avoid certain foods (like gluten & casein), why those foods are unique to each autistic child and more importantly, why they have a problem digesting those foods in the first place.

    What I have found clinically, and this can be linked to numerous chronic health issues in virtually anyone, is that you must identify and address the root cause of metabolic dysfunction & inflammation in the body.  This includes genetic predispositions, generalized toxicity and impaired intestinal function.  Further, if we take a close look at the presentation of ASD kids specifically, we come to recognize that they tend to be in a state of inappropriate neurological & immune activation due to these underlying causes.


    So what really is a food allergy?

    An allergen is defined as a substance, normally harmless in most healthy individuals, that provokes symptoms in affected individuals.  All allergies (food & environmental) cause a reaction within the immune system involving antibodies called immunoglobulins (Ig).  Immediate allergic reactions, known as Type I hypersensitivity reactions, are the result of elevated blood IgE levels.  These occur in the first minutes to hours of exposure to a substance (i.e. peanuts, shellfish, bee stings) and induce symptoms ranging from redness & swelling and to even anaphylactic shock & death.  There is also Type IV delayed-hypersensitivity allergy reactions.  They result from elevated IgG activity and generally occur more than two hours after exposure.  They can elicit more subtle and lingering effects such as headaches, sinusitis, brain fog, IBS, joint pain and more.

    The IgG food allergy reaction however, is of primary concern here.  It represents a food “intolerance”, one that the body has come to gradually reject over time.  Sensitivity to gluten or casein common in ASD for example, can show up in IgG blood testing and is therefore referred to as an allergy.  But how do “allergies” to things like gluten manifest and affect autistic children amongst many other individuals?  The answer is deeper than diet.

    Importance of Optimal Digestion

    They say you are what you eat, but more accurately, you are what you absorb. Ideally, during our meals we’re relaxed, chew our food slowly & thoroughly, and secrete adequate amounts of acid & various enzymes so we can properly digest our food into small particles.  If all goes well, the cells of the small intestines permit the absorption of vital nutrients from the gut into circulation and present a barrier against toxins & large food particles.  This interface works in concert with our bacterial microflora to establish the healthy utilization of nutrients and the foundation of our immune function.

    However, one’s diet and digestion is usually far from perfect.  Various factors can disrupt this delicate balance of nutrient absorption & immune defense causing a myriad of physical and mental/emotional symptoms evident in ASD and many other chronic diseases.  If any facet of digestion is compromised, or if there’s exposure to certain foods, environmental triggers and even stress, larger undigested particles and toxins can “leak” their way in between our cells and eventually into the bloodstream.  The body identifies these substances as foreign and, in turn, mounts an autoimmune response…in this case, an IgG allergic reaction.

    Subsequently, a vicious cycle of local tissue damage, inflammation & dysbiosis ensues which can manifest into systemic issues, especially in the brain. For instance, when gluten and casein proteins pervade the gut inappropriately, they function like opiates or narcotics in children with autism, thereby impacting neurotransmitters and worsening behavior and cognition.

    Testing for allergies and

    digestive function

    Food sensitivities are unique to each person so it’s often more than just gluten and dairy.  Other common perpetrators include eggs, tomatoes, eggplant, avocado, red peppers, soy and corn. Observing behavior as it relates to the presence/absence of these and other foods is a great place to start, but a IgG antibody blood test is the most accurate way to identify food allergies and structure elimination diets.  Removing allergenic foods can drastically improve the diverse symptoms of ASD, but it is imperative to also assess digestion function.  This is done through either urine, blood or stool tests to assess the integrity and microbial balance of the gut.  Interestingly, most children with 4-A disorders (allergies, autism, asthma & ADD/ADHD) also have hypersensitivity to inhalants so it’s important to check for environmental allergies as well (mold, animal dander, dust, etc.).


    The Road to Healing

    Individualized restricted diets are pertinent to avoid exposure to aggravating foods, but it is only part of approach to the ASD puzzle. By addressing gut dysfunction as well as accompanying systemic imbalances, you can journey down the path of healing in ASD and many other disorders.

    In order to improve digestion function & immune function though (and therefore behavior), it is important to implement what I refer to as The Five R’s: Remove food allergens, Rebuild the intestinal mucosa, Reduce oxidative damage and inflammation, Restore normal flora and Rid your body of intestinal toxins.  There are specific nutrients help to support these issues and optimize digestive health. These include antioxidants, intestinal repair nutrients, digestive enzymes and probiotics.

     Putting it all together

    Autism is invariably accompanied by many medical issues and treating these issues often leads to improvements in the individual’s development.  When important systems in the body are not functioning in an optimal manner, the body is under a great deal of stress and inflammation.  It is then difficult for the child to focus and learn.  Removing some of these factors can help reduce the burden, making it possible for the child to focus on learning and benefit from therapy.  It is very important for parents to maintain a positive attitude. When provided with all round support – nutritional, medical, therapeutic, and emotional – children on the spectrum show progress and improvements in all developmental areas.

    Dr. Josh Donaldson is in private practice in Los Gatos, CA where his focus is on the natural prevention & treatment of disease through digestive health, nutrition, exercise, detoxification & mental health. He has been successfully treating ASD & associated disorders for several years and has also served as an Adjunct Professor at Cabrillo College and Five Branches University since 2006.  For more information, please visit or call (408) 358-7900.

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