Effect of postnatal fish oil supplementation in high risk infants on immune function and allergy development: a randomized controlled trial

[Truncated abstract] Allergic diseases have reached epidemic proportions in westernized countries over the last 30-40 years indicating that environmental and lifestyle changes must be responsible, although the mechanisms are unclear. It is imperative to identify ‘allergy promoting’ environmental factors with plausible biological effects, that can be modified for the primary prevention of allergic disease and there is strong interest in dietary changes with immunomodulatory properties. Among these, a significant decrease in dietary levels of relatively anti-inflammatory omega-3 (n-3) polyunsaturated fatty acids (PUFA) in favor of n-6 PUFA, has been associated with the allergy increase, which has logically lead to interest in the role of fish oil supplementation to restore n-3 PUFA status for allergy protection. Another core aspect of allergy prevention is the capacity to more accurately identify ‘at risk’ populations for targeted intervention. Notably, a novel allergy marker, namely protein kinase C zeta (PKCζ), is modified by fish oil, and a leading candidate for further investigation in the context of allergy prediction. The aims of this thesis were 1) to further investigate the predictive value of PKCζ expression at birth on allergy development (Chapter 4) and 2) to determine whether infant fish oil supplementation in the early postnatal period can favourably modify infant immune development (Chapter 5) and prevent allergy development (Chapter 6). Firstly, in a cohort of 135 infants of ‘mixed’ allergic risk (selected from the clinical trial described below and a parallel control study) we affirmed a predictive association between low neonatal T cell PKCζ expression at birth and allergic disease by 12 months of age (Chapter 4).