The Relationship Between Iron Deficiency and ADHD
Iron deficiency is strongly associated with behavioral disturbances in children, including decreased attention to tasks, which can manifest as or exacerbate symptoms of ADHD. 1
Iron's Role in Brain Function and ADHD
- Iron is essential for proper brain development and cognitive function, particularly for the dopaminergic neurotransmitter system, which is implicated in ADHD pathophysiology 2
- Iron deficiency, even without anemia, can lead to altered neurotransmitter function that may contribute to ADHD symptoms 3
- Brain iron deficiency has been observed in several regions in children with ADHD, including bilateral striatums, anterior cingulum, olfactory gyrus, and right lingual gyri 4
Clinical Evidence of the Relationship
- Iron deficiency anemia in children results in developmental delays and behavioral disturbances, specifically decreased motor activity, social interaction, and attention to tasks 1
- These developmental delays may persist past school age (beyond 5 years) if iron deficiency is not fully reversed 1
- Studies show that children with ADHD have significantly lower serum ferritin levels compared to control groups 2, 5
- Iron deficiency anemia makes a child 3.82 times more prone to developing ADHD 2
ADHD Subtypes and Iron Deficiency
- Iron deficiency appears to be more prevalent among the inattentive subtype of ADHD (38% vs 22% in other subtypes) 6
- Treatment with iron supplements has shown better response in the inattentive subtype of ADHD compared to other subtypes 6
Familial and Genetic Factors
- Children with ADHD and a positive family history of Restless Legs Syndrome (RLS) appear to represent a subgroup particularly at risk for severe ADHD symptoms 5
- Both a positive family history of RLS and previous iron supplementation in infancy were associated with more severe ADHD scores 5
Treatment Implications
- Iron supplementation may be beneficial in treating ADHD symptoms in children with iron deficiency 6
- Treatment with ferrous sulfate (4 mg/kg/day) for 3 months has shown complete symptom control in some patients with the inattentive subtype of ADHD and iron deficiency 6
- Oral iron supplementation may be less effective than intravenous iron for replenishing iron stores in severe deficiency cases 1
Diagnostic Considerations
- Quantitative Susceptibility Mapping (QSM) brain imaging technique may have potential efficacy in the auxiliary diagnosis of ADHD by detecting brain iron deficiency 4
- When evaluating children with ADHD, clinicians should consider screening for iron deficiency, RLS, and family history of RLS 5
Potential Mechanisms
- Iron deficiency may contribute to ADHD symptoms through its impact on the dopaminergic system, which is critical for attention and impulse control 3
- Iron deficiency also increases the gastrointestinal tract's ability to absorb heavy metals, including lead, which can further impact neurodevelopment 1
Clinical Pitfalls and Caveats
- Iron deficiency often coexists with other factors that may independently affect child development (low birthweight, generalized undernutrition, poverty, high blood lead levels) 1
- Not all children with ADHD have iron deficiency, suggesting that iron deficiency is one of multiple potential contributing factors to ADHD symptoms 2, 4
- Clinicians should be careful not to attribute ADHD symptoms solely to iron deficiency without comprehensive evaluation 1