Higher Docosahexaenoic acid, lower Arachidonic acid and reduced lipid tolerance with high doses of a lipid emulsion containing 15% fish oil: A randomized clinical trial

Background & aims: Lipid emulsions containing fish oil, as source of long chain omega 3 fatty acids, have recently became available for parenteral nutrition in infants, but scanty data exist in extremely low birth weight preterms. The objective of this study was to compare plasma fatty acids and lipid tolerance in preterm infants receiving different doses of a 15% fish oil vs. a soybean oil based lipid emulsion. Methods: Preterm infants (birth weight 500-1249 g) were randomized to receive parenteral nutrition with MOSF (30% Medium-chain triglycerides, 25% Olive oil, 30% Soybean oil, 15% Fish oil) or S (S, 100% Soybean oil) both at two levels of fat intake: 2.5 or 3.5 g kg(-1) d(-1), named 2.5Fat and 3.5Fat respectively. Plasma lipid classes and their fatty acid composition were determined on postnatal day 7 and 14 by gas chromatography together with routine biochemistry. Results: We studied 80 infants. MOSF infants had significantly higher plasma phospholipid Docosahexaenoic acid and Eicosapentaenoic and lower Arachidonic acid. Plasma phospholipids, triglycerides and free cholesterol were all significantly higher in the MOSF-3.5Fat group, while cholesterol esters were lower with MOSF than with S. The area under the curve of total bilirubin was significantly lower with MOSF than with S. Conclusions: The use of a lipid emulsion with 15% FO resulted in marked changes of plasma long-chain fatty acids. Whether the benefits of increasing Docosahexaenoic acid outweigh the potential negative effect of reduced Arachidonic acid should be further studied. MOSF patients exhibited reduced lipid tolerance at 3.5 g kg(-1) d(-1) fat intake.