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Cross-Reactivity, Allergens, & the Biochemical Impact on ADHD & Autism

Catkins of a Corylus avellana plant in spring

In mice with cow’s milk allergy, diets that reduce mTOR activity in the prefrontal cortex and amygdala improve behavioral problems similar to those seen in autistic children. This suggests mTOR may be a mechanism of action by which allergies can lead to autistic symptoms.

The sensitization to dietary proteins (especially to wheat, cow’s milk, and soy) that occurs in children with ASDs may be due to an abnormal innate immune response that leads to GI inflammation and exacerbation of behavioral symptoms. Gastrointestinal and behavioral symptoms experienced by children with ASDs often resolve when an elimination diet is implemented.

Cross-reactivity refers to the fact that people sensitized to inhaled allergens also react to specific types of fruits, vegetables, and even in some cases animal protein. It is estimated that 80% of all cases of food allergy in adults are preceded by a clinical or subclinical sensitization to inhaled allergens. A substantial percentage of ADHD patients are sensitized to Bermuda grass. Many people who are allergic to Bermuda grass also react to cantaloupes and tomatoes. There is also a high prevalence of dust mite sensitization in children with ADHD. Dust mites cross-react with shrimp and mollusks.

Therefore it is important for clinicians to be aware that children with ADHD or ASDs who react to airborne allergens may also exhibit behavioral and other symptoms after ingesting cross-reacting foods. Antibody assessment panels measuring IgE, IgA, and IgG can help determine which foods may pose a problem.


A strong link exists between childhood neurological disorders and inhaled allergens and food allergies/intolerances. Prevalence of allergic disorders is high in children with ADHD or autism. In these children, cross-reactivity between inhaled allergens such as pollens and various foods can occur. This leads to a possible exacerbation of ADHD or ASD symptoms in children sensitized to inhaled allergens who consume the corresponding food or foods. Furthermore, there is a high prevalence of celiac disease in this group of patients and gluten-free diets often resolve symptoms. As always, I prefer to test rather than guess. Thus, I recommend all patients with ADHD and ASDs undergo celiac antibody panel that includes both IgG and IgA and to test for food allergies and intolerances using the antibody assessment panels.

Watch US BioTek's webinar on how immunity-related genes may be linked to ADHD and Autism: 

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Click below to refresh your knowledge on IgG food sensitivity testing:

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2. J Methodol. 2015 June 26;5(2):31-50.
3. Hautarzt. 2001 Aug;52(8):708-11.
4. Asian Pac J Allergy Immunol. 2011 Mar;29(1):57-65.
5. J Methodol. 2015 June 26;5(2):31-50.

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