Iron deficiency causes abnormal functioning of the brain neurotransmitter dopamine and may contribute to the 'physiopathology' of ADHD, note Dr Eric Konofal, of Hopital Robert Debre in Paris, and his colleagues in this month's Archives of Pediatrics and Adolescent Medicine (158, pp1113-1115).
The researchers assessed blood iron levels of 53 children with ADHD, aged four to 14 years old, and 27 controls.
Serum ferritin levels were abnormal in 84 per cent of children with ADHD and 18 per cent of controls.
In addition, low serum ferritin levels were correlated with more severe general ADHD symptoms measured with Conners' Parent Rating Scale and greater cognitive deficits.
"These results suggest that low iron stores contribute to ADHD and that ADHD children may benefit from iron supplementation," write the researchers.
This could decrease the need for medication, they suggest.
Iron deficiency with anaemia affects about 25 per cent of infants worldwide and twice as many have iron deficiency without anaemia.