All Year 11 pupils will be signing-up to take the supplement eye q for the next nine months. The initiative, which is the largest programme using fatty acids in the classroom, is the brainchild of Dave Ford, the county council's chief schools inspector. He has followed the progress of children in earlier studies taking the supplement, and is convinced that the same improvements in concentration and learning, if applied to Year 11 pupils, could have a direct impact on their GCSE results.
The countywide trial at 36 schools will continue until pupils complete their exams next summer. The first test will be when they sit their mock GCSEs in December.
"We are able to track pupils' progress and measure whether their attainments are better than their predicted scores," said Mr Ford.
Over the past four years, the level of GCSE attainment at five or more A* to C grade passes in the county has improved by more than 15 per cent - far ahead of the national average increase.
This year, the percentage of pupils gaining five or more grades of C or above topped 56 per cent, which was 5.5 per cent up on 2005, but below the national average of 62.4 per cent.
Durham education officials believe students can dramatically close the gap on the national average next year - maybe equalling it - by taking the supplements.
The county council ran a trial for young children four years ago. Twelve school offer the eye q supplement to pupils aged six to 12 as part of a double blind, placebo controlled study. Significant improvements were seen in attention, hyperactivity and short-term memory. Achievements in reading and spelling were also highly significant.
Since then, teenagers from Greenfield Community College also saw improvements in behaviour and attention after taking the supplement.
Infants attending three SureStart early years centres saw gains far beyond expectation in behaviour, concentration and language developments after taking the fish oils.