The most significant factor that has changed for children in the last 20 years is their diet

Dr Madelaine Portland

Supplements of omega three, which is found in fish, and omega six, found in plants, plant and fish extracts will be given to the pupils at specific stages over the six-month trial period.

The research is based on the belief that deficiencies in fatty acids can cause serious learning difficulties which are more to do with a child's metabolism than his or her neurological condition.

The study is being carried out in 13 primary schools across County Durham under the lead of the senior educational psychologist for the county education authority, Dr Madelaine Portland.

"In the past 20 years there have been massive increases in the numbers of children diagnosed with these disorders - as many as four or five times more," Dr Portwood said.

"This is certainly not down to better recognition of these conditions.

"The most significant factor that has changed for children in the last 20 years is their diet."

Dr Portland said it was highly likely that the problem for most children with learning difficulties was not neurological but metabolic - and therefore treatable with supplements.

The pupils would not be asked to give anything up in their diet, therefore allowing researchers to determine that a deficiency in the diet was to blame.

Breath test

The researchers will identify fatty acid deficiencies by means of a breath test, rather than a blood test.

"So it's totally non-invasive," said Dr Portland.

And, in the long term, it could lead to universal screening for young children to identify learning disorders before they start to struggle.

The research is being funded by the Dyslexia Research Trust in Oxford, with the supplements provided by Equazen Nutraceuticals.

Breakfast clubs

Details of the research came as a survey found school breakfast clubs - which offer pupils a decent meal before the start of the school day - could help cut truancy rates and enhance pupils' academic performance.

Three quarters of the 33 schools studied said the clubs had improved attendance and punctuality.

And 80% said pupils concentrated better in class.

Half of the schools questioned by Kellogg's noticed improvements in pupils' work.