<p>Of the three components of parenteral macronutrient classes (protein, carbohydrate and lipid), the lipid class is the least understood and the fatty acid distribution in lipid emulsion products has the potential to play a critical role in the development of infant morbidities. Breast milk has long been considered the gold standard for infant nutrition, but when infants cannot tolerate enteral feeds, the use of lipid emulsions cannot be avoided despite their adverse side effects.</p> <p>In this study, fatty acid profiles from five commercially available lipid emulsion products were compared to the profile of breast milk. As well, resulting serum on each of these nutrition sources were compared to the profile of either lipid emulsion (Intralipid) or breast milk. Fatty acid profiles for matched pairs of breast milk from mother and resulting serum from infants were compared as well as the profile of normotriglyceridemic serum samples to hypertriglyceridemic ones. Results indicate that not one lipid emulsion product is like another, nor do their profiles closely resemble breast milk even though they are intended to replace the fat portion of the infant’s natural source of nutrition. Serum was not found to directly reflect the fatty acid profile of the nutrition source administered, as was expected based on literature, highlighting that there is a complex web of pathways between nutrition administration and appearance of fatty acids in the serum. Further research is necessary to define the effect of fatty acid chain length and degree of saturation on these metabolic pathways, as the very essence of interrelations such as these can complicate interpretations of results.</p> / Master of Science in Medical Sciences (MSMS)