Primary objective of this study is to examine the effects of 2 different approaches of dietary strategies to optimise fatty acid composition in complementary food on infant's fatty acid status and its consequences on cognitive and visual development.

Subjects are randomly assigned to one of three groups:

• Rapeseed oil (high in n-3 PUFA and small n-6:n-3 ratio to support endogenous n- 3 LC-PUFA metabolism)
• Fatty fish (preformed n-3 LC-PUFA, especially DHA)
• Corn oil (as control group, high in n-6 PUFA, common in complementary food).

The intervention starts with the beginning of complementary feeding as generally recommended between 4 to 6 months of age and ends at the age of 10 months. For this period of time subjects of all groups receive commercial vegetable-potato-meat-meals as part of complementary food which only differs in the fatty acid composition.

A well balanced supply of polyunsaturated fatty acids, in particular the omega-3 long chain docosahexaenoic acid (DHA), in early childhood is essential for children's cognitive and visual development. DHA can either be supplied preformed in the diet (e.g. via fatty fish) or synthesised by conversion of its essential precursor alpha-linolenic acid (e.g. via rapeseed oil). The study examines the effect of two different approaches to optimise infants´ fatty acid status.

The study sample consists of healthy newborns and their mothers (3 x 57 infants according to a priori power calculation) who are enrolled in delivery hospitals in the region of Dortmund, Germany. In total, the individual study program covers the first 10 months of infant's life. Biomarkers of fatty acid status from the mother are collected 8 weeks pp for the estimation of pre- and perinatal fatty acid supply. Additionally, information on maternal diet during pregnancy and after delivery is assessed. The intervention covers the period of complementary feeding (from 4 to 6 months of age until 10 months of age). In all groups the specific study food is given 5 to 7 times a week, whereas 2 of these are fish meals in the fatty fish group. At the age of 4 and 10 months blood samples are collected from the infants to examine the effect on blood fatty acid status. Parameters of visual and cognitive development are also assessed at the age of 4 and 10 months using VEP examinations and Bayley scales. Infants´ dietary intake is assessed from the end of the 2 months until 10 months of age using continuous weighed dietary records.

Inclusion Criteria:

• a term healthy newborn infant ( birth weight > 2500 g, gestational age > 37 weeks
• German speaking mother
• the intention of the mother to breast-feed the children and to feed study menus at least 5 times per week beginning in the fifth to seventh month of life.

Exclusion Criteria:

• preterm children
• twins