Iron deficiency in Australian children you would expect to be a rare occurrence. So why am I seeing so many children in practice that are obviously anaemic or have sub-optimal levels of iron?
Iron is essential not only to ensure that children do not develop anaemia but to ensure adequate growth and learning through optimal development of neural processes. Studies over the last 20 years clearly show a link between low iron and learning difficulties in children. More recent research is showing a higher incidence of psychiatric disorders as well.
To emphasise this point, a Taiwanese study in 2013 that looked at 2957 children and adolescents with iron deficiency anaemia and 11,828 healthy controls, found that iron deficiency anaemia is associated with an increased risk for psychiatric disorders. After adjusting for demographic data and risk factors, children and adolescents with iron deficiency anaemia were at higher risk for the following:
- Unipolar depressive disorder
- Bipolar disorder
- Anxiety disorder
- Autism spectrum disorder
- Attention-deficit/hyperactivity disorder
- Tic disorder
- Delayed development
- Mental retardation
A study that looked at low-birth-weight babies who did not receive iron supplements were 4.5 times more likely to show signs of behavioural problems at age 3 compared with low-birth-weight babies who received iron supplements during early infancy. Low-birth-weight babies grow rapidly and may not receive enough iron from their mothers in utero to last them during the first few months of life. Signs of behavioural problems, including attention problems, were seen in 12.7 percent of children who did not receive iron supplements. By contrast, only about 3 percent of children who received an iron supplement and 3 percent of children in the healthy weight group showed signs of behavioural problems.
Of the 19 babies with signs of behavioural problems, 15 had an iron intake of less than 1 mg/kg per day. The results held regardless of whether or not the babies were breastfed or formula fed.
According to the American Academy of Pediatrics recommendations, healthy babies should also receive iron supplements starting at 4 months of age if they are breastfed. I am not aware of any paediatricians in Australia recommending mothers give additional iron to their breastfed babies.
Iron is an important micronutrient in the diet of very young children. In animal studies, iron has been shown to be essential for brain cell development.
Iron, ADHD and Antipsychotics
Interest in studying the role of iron in ADHD is not new, as the earliest studies were conducted over 20 years ago. Low serum iron levels in iron-deficient infants, children and adolescents are strongly correlated with cognitive deficits similar to ADHD symptoms (e.g. reduced attention, motivation, working memory, motor control).
Of note is that normal serum iron levels do not exclude the possibility of abnormal brain iron levels in ADHD. In fact, animal studies have reported the association of low brain iron with disrupted neural processes implicated in ADHD, including dopamine abnormalities. Specifically, a fundamental relationship between brain iron and dopamine metabolism has been demonstrated through iron’s role as a required cofactor for dopamine synthesis.
A recent systemic review has highlighted that it is the ferritin (iron store) levels that are more important than serum iron to assess in ADHD. Another study found that ferritin levels >30µg/L (normal reference range is usually 7 – 140µg/L) were associated with a lower incidence of ADHD.
Parents with children that have been prescribed the antipsychotic risperidone, should be aware that the long-term use of risperidone can lead to iron deficiency. Therefore, it would be wise to have regular bloodwork done to assess iron and iron stores in any child on long-term risperidone.
In clinical practice, I find that parents often find considerable resistance from medical practitioners to order blood tests for paediatric patients. Perhaps even more alarming I see many blood pathology reports that parents present to me saying that their doctor has told them that everything is “normal” on the report. On reviewing the test results, they are clearly not “normal”. I would strongly urge all parents to always request a copy of their children’s test results and wherever possible get them reviewed by a practitioner that can look at the results in the context of the patient’s symptoms.