The effects of high-dose fish oil supplementation during early infancy on neurodevelopment and language

[Truncated abstract] This thesis addresses the role of fish oil supplementation during early infancy for optimal neurodevelopment. Fish oil is high in omega-3 (n-3) long-chain polyunsaturated fatty acids (LCPUFA), including docosahexanoic acid (DHA) which is found in high concentrations within the brain and retina, and affects a number of processes during early development. From the beginning of the third trimester of pregnancy til the end of the second year of life, the brain content of DHA increases by 30 fold (Martinez 1994; Lauritzen, Hansen et al. 2001), and DHA is functionally important for membrane biogenesis, and such events as neurogenesis, neuronal migration and outgrowth (Innis 2007). While n-3 LCPUFA are desaturated internally from the precursor ALA, several authors have argued that the conversion to LCPUFA is low within infants (Carnielli, Wattimena et al. 1996; Salem, Wegher et al. 1996; Carnielli, Simonato et al. 2007), and not sufficient to meet the high demands for n-3 LCPUFA during the critical early stages of development. The potentially low levels of infant desaturation of n-3 LCPUFA together with the decline in the consumption of n-3 LCPUFA due to increasing Western dietary patterns have led to concerns for the quantity supplied during early development. Adequate intake for pregnant and lactating women has been recommended to be between 200-300mg per day (Simopoulos, Leaf et al. 1999; Koletzko, Cetin et al. 2007); however median intakes of DHA can be as low as 30 – 50mg (Meyer, Mann et al. 2003; Makrides 2009). Breast milk DHA is similarly affected by maternal diet, and countries that experience typically low levels of DHA within breast milk are Western nations such as the USA (0.2%), Canada (0.14%) and Australia (0.25%). Infant formulas fortified with LCPUFA are commercially available in Australia. They are typically supplemented with LCPUFA to a level similar to mean breast milk levels.