Exploring the Role of Nutrition and the Gut–Brain Axis in ADHD.

The Link between Nutrition and Attention Deficit Hyperactivity Disorder (ADHD): Improving Gut Health and ADHD through reducing ultra-processed foods and using micronutrient supplementation.

Introduction: Understanding ADHD

Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental condition that affects both children and adults. It is characterised by patterns of inattention, hyperactivity, and impulsivity that significantly impair daily functioning across educational, occupational, and social settings.

A diagnosis of ADHD requires symptoms to be present for a minimum of six months and is classified into three subtypes: predominantly inattentive, predominantly hyperactive-impulsive, and combined presentation (DSM-5). ADHD is relatively common, with prevalence estimates suggesting that approximately one in twenty individuals are affected in Aotearoa New Zealand.

The aetiology of ADHD is multifactorial, involving a complex interaction between genetic predisposition, neurological development, and environmental influences. When left untreated, ADHD can be debilitating. Conventional treatment approaches include:

• Pharmacological interventions

• Cognitive behavioural therapy (CBT)

• ADHD coaching

• Individualised educational plans (IEPs)

• Classroom-based strategies

Ongoing support for parents, caregivers, and educators is also an essential component of effective management.

ADHD frequently co-occurs with other neurodevelopmental and mental health conditions, including:

• Dyslexia

• Dyscalculia

• Dyspraxia

• Anxiety disorders

• Depression

Many individuals with ADHD experience additional challenges, such as sensory processing difficulties, food sensitivities, and impaired interoceptive awareness, including difficulty recognising hunger and thirst cues.

Emerging research suggests that gut health, omega-3 fatty acids, specific nootropic compounds (e.g., Hericium erinaceus / Lion’s Mane), and broad-spectrum micronutrient supplementation may contribute to a reduction in ADHD symptom severity for some individuals. Regular physical activity has also been shown to be beneficial, potentially by helping to regulate stress hormones such as cortisol and supporting neurotransmitter production, including dopamine and serotonin.

Nutrition and ADHD

Environmental and genetic factors contribute to the development and maintenance of ADHD, with behavioural therapy and medication remaining the standard treatments. However, growing evidence suggests that dietary factors may also influence the severity and persistence of ADHD symptoms. Diets low in essential micronutrients and high in ultra-processed foods have been increasingly associated with poorer behavioural and cognitive outcomes.

This research article examines the relationship between nutrient-deficient diets and ADHD and explores how reducing ultra-processed food intake while ensuring adequate micronutrient consumption may support gut health and improve ADHD-related symptoms. The benefits of a nutritionally rich diet that promotes a healthy gut, alongside overall physical health, highlight potential biological pathways involved in ADHD and inform recommendations for future research.

Over recent years, a substantial body of research has emerged linking nutrition to mental health. Evidence increasingly demonstrates that dietary intake plays a crucial role in emotional wellbeing and cognitive functioning. While ADHD is a multifaceted condition, research indicates that:

• High consumption of ultra-processed foods

• Low intake of fresh fruit and vegetables

may exacerbate ADHD symptoms.

The Gut Microbiome and ADHD

The gut microbiome is composed of trillions of bacteria and plays a crucial role in the bidirectional communication between the gut and the brain. Emerging research suggests that imbalances in the gut microbiome, known as dysbiosis, are associated with mental health disorders such as ADHD.

Ultra-processed foods can disrupt the gut microbiota, leading to inflammation in the gut, often referred to as “leaky gut syndrome.” This disruption can result in poor absorption of key vitamins and minerals from the diet.

Popper, Bonnie and Rucklidge explain that it is often assumed that individuals living in well-developed countries consume adequate amounts of nutrients and micronutrients through their daily diet. However, research increasingly shows that this assumption is inaccurate. Several factors contribute to widespread nutritional deficiencies, including:

• Intensive farming practices

• Use of glyphosates, which bind to micronutrients and reduce their bioavailability

• Food industry practices

• Heavy reliance on convenience foods and takeaways

These foods tend to be high in additives and preservatives while being low in essential nutrients. Modern farming methods combined with increased consumption of ultra-processed foods reduce micronutrient intake, disrupt the gut microbiota, and promote inflammation.

Key Nutrients That Support ADHD

Research indicates that specific nutrients may help alleviate ADHD symptoms, including:

• Omega-3 fatty acids

• B vitamins

• Folate

• Antioxidants

• Vitamins C and E

• Zinc

• Iron

• Magnesium

• Prebiotics and probiotics

Evidence also highlights the crucial role of daily activity and exercise in supporting individuals with ADHD. In their literature review, Fotoglou, Moraiti, Diamantis, Stergios, Gavriilidou and Drigas describe how a nutritious diet combined with regular physical activity can be a “game changer” for individuals struggling with ADHD. Fotoglou et al. (2022) report that children with ADHD have lower levels of DHA omega-3 compared to those without the condition, underscoring the importance of omega-3 in the diet.

They also emphasise the importance of adequate omega-3 intake for women during prenatal and postnatal periods, particularly during the third trimester and the first six months of life, as this is critical for neurodevelopment.

Sources of omega-3 fatty acids include:

• Fatty fish

• Walnuts

• Flaxseeds

These fats are essential for supporting:

• Cognitive development

• Language skills

• Emotional regulation

• Proprioception and motor skills

They also contribute to the structure of brain cell membranes and support the production of neurotransmitters such as serotonin, which plays a key role in mood regulation.

Other critical nutrients include zinc, iron, and magnesium. These minerals are involved in the synthesis of dopamine, serotonin, and melatonin and play an important role in the dopaminergic system. Research suggests that adequate levels of zinc, iron and magnesium may help reduce impulsivity and improve focus and attention. Studies have shown that children diagnosed with ADHD tend to have lower zinc and ferritin levels than the general population, indicating that increasing these minerals in the diet may be beneficial.

Sources of zinc, magnesium, and iron include:

• Shellfish

• Oily fish such as tuna, salmon and sardines

• Meat

• Leafy green vegetables

• Cereals

• Nuts

Dietary Patterns That Support Mental Health

The Mediterranean Diet

Characterised by a rich intake of fruits, vegetables, legumes, whole grains, protein sources, fish, and olive oil, the Mediterranean diet has demonstrated notable health benefits. Research suggests it is associated with:

• Increased life expectancy

• Improved mood

• Enhanced focus and attention

Elimination-Based Diets

Diets that remove ultra-processed foods, artificial additives, colourings, and preservatives, such as the Feingold diet, have shown promise in reducing ADHD symptoms. When combined with:

• A well-balanced micronutrient regimen (e.g., Hardy Nutritionals daily essential nutrient)

• Omega-3 supplementation

Longitudinal studies consistently report a reduction in ADHD symptoms.

Medication and Alternative Approaches

While medication can play a vital role and has significantly benefited many individuals with ADHD, it is also associated with a range of side effects. For some, these side effects may outweigh the benefits, leading to discontinuation or avoidance. Furthermore, there is a notable lack of long-term studies examining the effects of ADHD medication on children, raising uncertainty about lasting impacts on the developing brain.

Although these medications can help children focus and remain seated in school, parents often report noticeable changes in their child’s personality.

The Role of Neuroplasticity and Epigenetics

Research has shown that the nervous system has remarkable neuroplasticity, allowing it to adapt neuronal pathways, promote growth, and facilitate repair. Epigenetics demonstrates that genes can be activated or deactivated in response to environmental factors, a process closely linked to the microbiome, which can influence gene expression and neurotransmission.

There is growing recognition of the benefits of supporting mental wellbeing through:

• Maintaining a healthy gut

• Ensuring adequate intake of essential micronutrients

• Engaging in regular physical activity

These approaches are safe, low-risk strategies that may help alleviate ADHD symptoms while supporting overall health.

Conclusion

The expanding body of research on nutrition and physical activity consistently highlights their positive impact on mental health. Evidence shows that a well-rounded diet and regular exercise, combined with a reduction in ultra-processed foods, can support:

• Improved cognitive function

• Enhanced focus

• Better emotional regulation

• Overall well-being

The fields of nutrition and psychology are rapidly evolving, with increasing compelling research. While further studies are needed to establish precise guidelines for specific micronutrients and personalised dosages, the connection between gut health, nutrients, and mental well-being is becoming increasingly clear.

Embracing a nutrient-rich diet, such as the Mediterranean diet, while reducing reliance on ultra-processed foods offers a holistic approach to supporting mental health conditions such as ADHD.

If you would like to discuss health and nutrition coaching, feel free to get in touch. Let’s have a conversation about how I can support you in achieving your nutritional goals.

 

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