ADHD and Food Sensitivities: A Review of the Medical Literature

By Published On: January 15th, 2025

By: Dr. Megan Druet, ND 

While ADHD symptoms have long been tied to aberrancy in the prefrontal cortex neural circuits, emerging evidence suggests that some individuals diagnosed with ADHD also (or instead) may have a food sensitivity that is the true culprit that is manifesting their neurological-based symptom picture. 

What is ADHD?  

ADHD is a neurodevelopmental disorder that starts in childhood and is characterized by patterns of executive dysfunction, including attention dysregulation, hyperactivity, and impulsivity. 

This is a multifaceted disorder with biological and environmental underpinnings and can vary in symptom manifestation. It is estimated that approximately 5.29% of people have been diagnosed with ADHD [1]. A diagnosis of ADHD is achieved via a questionnaire and by ruling out other possible differential diagnoses. 

What are Food Sensitivities? 

The term food sensitivities, otherwise known as adverse food reactions, is a broad term that encompasses three subcategories. 

Psychological – allergies that are a result of classical conditioning to certain foods. 

Non-toxic – individualized allergies based on the individual’s immune system. 

Toxic – adverse food reactions to well-known harmful substances that happen in everyone (ie. food colouring, additives, bacterial metabolites) 

This review will focus on non-toxic individual IgG immune system-based food sensitivities.  

This type of food sensitivity is a negative reaction to food that is usually associated with increased levels of certain IgG class antibodies that are reactive to that food. Unlike a true food allergy, the symptoms can be delayed for up to a few days after ingesting the trigger food. 

Forging the Connection Between ADHD and Food Sensitivities 

A century ago, the connection between food sensitivities and seemingly unconnected characteristics, such as restlessness and sleep disorders, was first observed. Initial studies found that foods such as eggs, grains, and tomatoes resulted in a reduction and, in some cases, the disappearance of ADHD symptoms. 

The oligoantigenic diet (OD), otherwise known as the elimination diet, is a product of the allergy identification field used to determine which foods cause allergic reactions. In 1983 the OD was first utilized for the specific purpose of addressing the symptoms of ADHD, and the results were a significant breakthrough in the field.  

Of the 76 children participating in the study, 62 showed a reduction in ADHD symptoms, offering substantial proof that an elimination diet can reduce ADHD symptoms. Even more, 21 of the participants were no longer displaying symptoms that classified them as having ADHD, suggesting their ADHD diagnosis was, in fact, a food sensitivity all along. Once the food was removed, their ADHD symptoms disappeared as well.  

To further prove this connection, the study reintroduced the triggering foods and observed the reappearance or intensification of ADHD symptoms. [2] 

An Expansion of Evidence 

While the 1983 study was monumental in the information it obtained regarding food sensitivities, ADHD symptoms, and the oligoantigenic diet as a solution, research has only expanded since then. 

Numerous studies have shown the connection between nutrition and ADHD symptoms, with many studies exhibiting significant results when utilizing elimination diets. [3, 4, 5, 6] 

In a study looking to analyze the connection between diet and behavior in a randomized group of children, 100 children diagnosed with ADHD were randomly assigned to the instructions for a healthy diet (control group) or a 5-week restricted elimination diet (diet group). Results at the end of this trial show an ADHD rating scale (ARS) total score difference between the diet and control groups of 23.7. [7] 

Yet another study, completed in 2021, concluded that the most effective way to identify food intolerances is through an OD. The trial enrolled 28 children with ADHD. In the initial stages of the trial, the children kept a journal detailing nutrition and behaviors where they used the abbreviated Conners’ scale to help identify foods that increase ADHD symptoms. 

The study then enlisted 16 children to complete a four-week elimination diet. After the four weeks, foods were reintroduced to identify food sensitivities. Across all 16 children, 27 food sensitivity reactions were recorded, with many participants sensitive to more than one food. 

These results further establish utilizing a combination of OD and subsequent food challenges to identify food sensitivities in those diagnosed with ADHD. [8] 

Reflecting on the Connection Between Food Sensitivities and ADHD Symptoms 

Since its first discovery a century ago, the connection between nutrition and ADHD symptoms has been repeatedly verified by research spanning a variety of trial types, proving that food intolerances can worsen ADHD symptoms. Putting these discoveries into action, the OD has been tested and proven to be an effective method of determining food sensitivities and decreasing ADHD symptoms.  

In some cases, the ADHD symptoms disappear entirely with the application of the OD, leading researchers to conclude that, for some children, the sole contributor to ADHD symptoms is a sensitivity to certain foods and is not a classical ADHD case. 

Synthesis of These Results into Your Practice 

In light of the evidence that exists between food sensitivities and ADHD, this is a clear sign that food sensitivities should always be on your differential diagnosis list when treating both kids and adults with ADHD.  

Be sure to complete either the OD or pursue blood testing to rule out immunogenic foods that could be resulting in your patient’s executive dysfunction. I can attest to this clinically that I have seen many patient’s improve with removing food sensitivities alone, allowing the gut to heal and their symptoms to improve.  

Tips for Performing the Oligoantigenic Diet in Kids: 

  • Keep a food and symptom diary – this is imperative for the food reintroduction to determine offending foods, but also is helpful to see and quantify the shift in symptoms when starting to eliminate everything (fosters compliance)
  • Re-introduce 1 new food at a time
  • Have replacement recipes using ‘elimination-diet friendly’ foods figured out before starting
  • Involve the kids in the new recipe meal preparation (empowering)
  • Rid your house of all foods that will be eliminated to avoid any temptation
  • Have the whole family participate (if possible) for solidarity
  • Thoroughly explain this procedure and why you are doing it for your child to family and friends so they respect the ‘food rules’

References 

[1] Matthew Smith (2017). Hyperactive Around the World? The History of ADHD in Global Perspective, 30(4):767-787. doi: 10.1093/shm/hkw127 

 

[2] Egger, J., Graham, P., Carter, C., Gumley, D., & Soothill, J. (1985). CONTROLLED TRIAL OF OLIGOANTIGENIC TREATMENT IN THE HYPERKINETIC SYNDROME. The Lancet, 325(8428), 540-545. doi: 10.1016/s0140-6736(85)91206-1 

 

[3] Wolraich, M., Hagan, J., Allan, C., Chan, E., Davison, D., & Earls, M. et al. (2019). Clinical Practice Guideline for the Diagnosis, Evaluation, and Treatment of Attention-Deficit/Hyperactivity Disorder in Children and Adolescents. Pediatrics, 144(4). doi: 10.1542/peds.2019-2528 

 

[4] Sharma, A., & Couture, J. (2013). A Review of the Pathophysiology, Etiology, and Treatment of Attention-Deficit Hyperactivity Disorder (ADHD). Annals Of Pharmacotherapy, 48(2), 209-225. doi: 10.1177/1060028013510699 

 

[5] Pelsser, L., Frankena, K., Toorman, J., & Rodrigues Pereira, R. (2017). Diet and ADHD, Reviewing the Evidence: A Systematic Review of Meta-Analyses of Double-Blind Placebo-Controlled Trials Evaluating the Efficacy of Diet Interventions on the Behavior of Children with ADHD. PLOS ONE, 12(1), e0169277. doi: 10.1371/journal.pone.0169277 

 

 

[6] Dölp, A., Schneider-Momm, K., Heiser, P., Clement, C., Rauh, R., & Clement, H. et al. (2020). Oligoantigenic Diet Improves Children’s ADHD Rating Scale Scores Reliably in Added Video-Rating. Frontiers In Psychiatry, 11. doi: 10.3389/fpsyt.2020.00730 

 

[7] Pelsser, L., Frankena, K., Toorman, J., Savelkoul, H., Dubois, A., & Pereira, R. et al. (2011). Effects of a restricted elimination diet on the behaviour of children with attention-deficit hyperactivity disorder (INCA study): a randomised controlled trial. The Lancet, 377(9764), 494-503. doi: 10.1016/s0140-6736(10)62227-1 

 

[8] Yorgidis, E., Beiner, L., Blazynski, N., Schneider-Momm, K., Clement, H., & Rauh, R. et al. (2021). Individual Behavioral Reactions in the Context of Food Sensitivities in Children with Attention-Deficit/Hyperactivity Disorder before and after an Oligoantigenic Diet. Nutrients, 13(8), 2598. doi: 10.3390/nu13082598 

 

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Written by : Margarita Sherman