Parenteral lipid emulsions in the preterm infant: current issues and controversies

Parenteral lipid emulsions are a necessary component of nutrition for extremely low gestational age newborns until adequate levels of enteral intake are established. Historically, Intralipid, a 100% soybean oil emulsion, has filled this role. Newer multicomponent lipid emulsions containing a mixture of other oils, including olive oil and fish oil, are now available as options, although the regulatory approval for use in neonates varies worldwide. When dosed at currently published recommendations, each of these lipid emulsions meets total fat and energy requirements without a risk of essential fatty acid deficiency. Thus, when choosing which lipid emulsion to provide, the answer must be based on the metabolic differences induced as a result of these fatty acid-rich emulsions and whether the emulsions provide a health advantage or pose a health risk. The questions of induced fatty acid profiles, health benefit and health risk are discussed sequentially for multicomponent lipid emulsions. Despite the growing acceptance of multicomponent lipid emulsions, there is concern regarding changes in blood fatty acid levels and potential health risk without strong evidence of benefit. There remains no ideal parenteral lipid emulsion option for the preterm infant. Standardising future animal and human studies in lipid delivery with the inclusion of lipid metabolism data will iteratively provide answers to inform the optimal lipid emulsion for the preterm infant.