The purpose of this study is to determine whether DHA (in a daily dose of 600 mg.) will improve the behaviour and learning of normal children aged 7-9 years in mainstream state schools who are underperforming according to nationally standardized tests.

The study has two stages, as its primary aim is to find out whether there is a real link between children's fatty acid status and their reading and behaviour. Previous reviews have stated the importance of objective measures, as did our referees.

We will aim to address this by using well validated tests of reading and behaviour, and comparing results from these with children's fatty acid status as assessed from a pinprick blood sample. In Stage 1 we will primarily aim to establish the degree of association between fatty acid status and reading and behaviour. Secondarily, we will look at whether the children who have a higher DHA status have better sleep, and whether in turn they have better reading and/or behaviour, as previous work has suggested this.

In Stage 2 we aim to carry out a randomised trial where children will be given either DHA or a taste- and appearance-matched dummy capsule for 16 weeks. Neither the children, parents nor the researchers will know which children will get which treatment until the study is over.

Inclusion Criteria:

1. Children aged 7 - 9 years from mainstream state schools who are underperforming in literacy skills according to nationally standardized assessments of scholastic achievement at age 7 years (Key Stage 1 ). To be eligible, children must score below the 33rd centile for reading/writing, but within the normal range in at least one other domain.
2. English as a first language.

Exclusion Criteria:

1. Major learning disabilities or medical disorders
2. Taking medications expected to affect behaviour and learning
3. Taking fish oils already, or eating fish 2 times or more a week