Under-achieving children could benefit from ground-breaking research into how certain foods can boost brain power.
The supplements contained fish and evening primrose oil
More than 100 junior schoolchildren in County Durham took part in tests to see if taking food supplements can improve academic achievement.
Experts are hoping that youngsters will show improved learning and behaviour.
The study involves one in a series of trials carried out by Dr Alex Richardson, from the University of Oxford.
It involves giving fatty acid supplements or placebos to children aged between eight and 12.
Although teachers are excited by some of the apparent improvements in the behaviour of many youngsters, it is not yet known who has been taking the real capsules.
Dr Madeleine Portwood, an educational psychologist, with Durham education authority, said: "At the Durham primary head teachers conference 2001, I presented details of research linking nutritional deficiencies and learning difficulties.
"The possibility of running a large-scale trial in the county to consider the effects of dietary supplementation with under-achieving pupils in mainstream schools, proved very exciting."
A Durham Council spokesman said: "We were concerned that a significant number of pupils underachieved because they have particular problems concentrating and remaining on task."
He added: "For many, this can lead to difficulties with reading, spelling and other aspects of the curriculum.
"Pupils can feel isolated within their peer-group and suffer loss of self-esteem.
"With current research revealing that fatty acid deficiencies may be a factor connecting these learning difficulties, it was possible that for some pupils an improved diet would lead to improvements elsewhere.
"However, overturning the high-carbohydrate heavily- processed diets that children typically consume was always going to be a momentous task.
"The education department of Durham County Council has given its full support to the collaborative project, which could have far-reaching benefits for children and their families.
Other support for the research has come from the Dyslexia Research Trust, an Oxford-based charity.