The aim of this study is to assess the effects of giving a schoolmeal with fatty fish, a schoolmeal without fish or omega-3 capsules on Noregian adolescents cognitive performance (concentration and learning abilities), mental health statua and markers of nutritional status. In addition, to disentangle the effect of fatty fish eaten as food and the effects of omega-3 fatty acids taken as a supplement.

There has been an increased attention to the role of nutrition for learning abilities among schoolchildren. As the diet provides humans with energy and several essential nutrients, a balanced supply of all nutrients promotes not only physical growth and health, but also cognitive development, helping children to learn from infancy throughout adolescence and beyond. In a three-armed non-blinded intervention trial the investigators will test whether ingestion of a schoolmeal or omega-3 capsules will improve cognitive function among pupils in 9th grade at eight lower secondary school. The pupils will be randomised into three groups, one group will be served lunch with fatty fish, one group will be served similar lunch with meat/cheese (without fish) and one group will recieve omega-3 capsules three times week over a period of 12 weeks. At the beginning and at the end of the study, pupils should conduct cognitive tests, and blood-, urine- and hair samples will be taken. The pupils should also answer a questionnaire on their diet, physical activity, sleep pattern and mental health.

Inclusion Criteria:

• girls and boys at lower secondary schools (9th grade)

Exclusion Criteria:

• allergy or intolerance to the food or food ingredients in the study