Children with attention-deficit hyperactivity disorder (ADHD) should be put on restricted diets as a standard treatment, researchers have said.
Previous studies indicate a link between food allergies and ADHD, and the latest findings suggest that eliminating certain foods from a child's diet may improve the symptoms of the condition.
ADHD causes children to be over-active, impulsive and inattentive.
Researchers examined the effect of eliminating specific foods from the individually tailored diets of 50 children aged four to eight with ADHD.
As a comparison, another 50 children with ADHD from the same age group were put on a generally healthy diet.
Following blood tests showing immune responses to 270 different foods, further modification of the diets took place.
Results published in The Lancet medical journal reveal that children with the restricted diet showed significant improvements in their ADHD symptoms.
The authors, led by Professor Jan Buitelaar, from Radboud University, the Netherlands, wrote: 'We think that dietary intervention should be considered in all children with ADHD, provided parents are willing to follow a diagnostic restricted elimination diet for a five-week period, and provided expert supervision is available.
'Children who react favourably to this diet should be diagnosed with food-induced ADHD and should enter a challenge procedure, to define which foods each child reacts to, and to increase the feasibility and to minimise the burden of the diet.'
Drugs or behavioural treatments should be considered for children who do not respond to a dietary approach, said the researchers.