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  • Julie Fischer

Special Diets for Autism & ADHD: Do They Help?

Ten years ago, my son was diagnosed with Asperger’s Syndrome, an autism spectrum disorder (ASD). He has made tremendous progress over the past decade, in large part due to holistic, nutrition-based therapies. The knowledge base on autism and other neurodevelopmental, learning, and behavioral conditions has advanced significantly during that time as well. One area of research that has received quite a bit of increased attention is the use of special diets for autism and Attention-Deficit/Hyperactivity Disorder (ADHD) symptoms. Do these diets help, and if yes, how? That’s what we’ll explore in this post.

Diets for autism and ADHD, such as the gluten-free, casein-free (GFCF) diet and Feingold diet, have been a regular topic of discussion in parent groups for two decades. However, only in recent years have researchers produced evidence to support what parents and practitioners have known for some time: dietary interventions can make a big difference for kids with neurodevelopmental, learning and behavioral challenges.

What does the research say about special diets for autism & ADHD?

1. Gastrointestinal problems are common in ASD & ADHD

Numerous studies confirm that gastrointestinal (GI) issues are common in ASD and ADHD. Kids diagnosed with these conditions frequently experience chronic constipation, diarrhea, and abdominal pain. In addition, these GI symptoms often coincide with mood and behavioral changes. Researchers note that pain and discomfort frequently manifest as disruptive behavior, especially in children who can’t express themselves verbally. Studies have found that the GI problems common in ASD and ADHD are often the result of imbalances in gut bacteria, food sensitivities, or insufficient digestive enzymes. Dietary modifications and nutritional supplements can help address these GI issues and reduce associated mood/behavioral symptoms.

2. Gut health (and gut bacteria) plays a key role

A recent review of 24 research studies on gut microbiota in ASD and ADHD underscores the role of gut health in these conditions. Researchers have found that individuals with ASD and ADHD have variations in gut bacteria that differ from their neurotypical peers. While the studies note a stronger association between gut health and ASD symptoms, ADHD-associated bacterial variations have also been reported. A disrupted gut microbiome can negatively affect brain function via the gut-brain axis. This in turn affects behavior and learning ability. Additionally, the research shows that dietary interventions can reduce symptoms of both ASD and ADHD, perhaps by balancing gut bacteria.

3. Food allergies and sensitivities are more common in ASD & ADHD

Research shows that kids with ASD or ADHD experience significantly higher rates of food allergies and sensitivities than their typical peers. A large multi-year study that included data from close to 200,000 children found that food allergies are more than twice as common among autistic children. Research on the connection between food sensitivities and ADHD symptoms dates back to the 1970s. As this body of research has grown, it shows an average response rate to elimination diets (i.e., diets eliminating common allergens/sensitivities) among children with ADHD of 49%.

4. Dietary changes are associated with both cognitive and behavioral improvements

Dietary modifications have been linked to improvements in both ASD and ADHD symptoms. A randomized, controlled 12-month trial found that a gluten-free, casein-free, soy-free diet improved autism symptoms and non-verbal IQ in a significant percentage of autistic children and adults. The research shows that restriction and elimination diets are also effective for a subset of children with ADHD. Removal of food additives (i.e., artificial colors and preservatives) appears to be the most effective dietary intervention for ADHD. However, research has shown that diets that restrict foods based on an individual’s IgG food sensitivity test results also lead to significant improvements on the ADHD rating scale. As dietary modifications support better brain function, this can lead to improvements in attention, memory, and social/communication skills. Additionally, individuals who respond to dietary intervention generally experience a balancing effect on mood, mental health, and overall functioning.

How can you determine whether a dietary change will help?

The best way to find out whether diet may be contributing to symptoms is to do an elimination diet. This involves removing common allergenic foods and additives for a specific period of time. After the elimination period, the next step is to reintroduce foods, one at a time, to gauge reactions. The final step is to modify the diet as needed to remove identified sensitivities and prevent potential nutritional deficiencies. While an elimination diet does involve some planning and effort, it’s the most reliable way to determine whether a dietary change will be beneficial. Plus, it’s safe and should not require any extra expense. I’ll cover elimination diets in more detail in a future blog post!

If you’d like individualized dietary/nutritional support, I’d love to connect with you! My specialty is creating effective nutritional strategies to support brain functioning, mood, and behavioral health and I especially enjoy working with families of children with autism and ADHD. Visit my Work With Me page to learn more.

Julie Fischer Nutritionist and autism mom



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