Triglyceride Hydrolysis of Soy Oil vs Fish Oil Emulsions

Abstract

Background: Fish oil triglycerides (TG) are being considered for use in IV lipid emulsions, but the characteristics of their lipase-mediated clearance from plasma are largely unknown. Methods: We compared the in vitro hydrolysis of soy oil long-chain triglyceride emulsions (LCT) and fish oil emulsions (ω-3) using lipoprotein (LPL) and hepatic (HL) lipases. ω-3 emulsions contained 18% and 28% of total TG fatty acid as eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA), respectively. Results: Under conditions of maximal hydrolysis, total free fatty acid (FFA) release was two- to threefold greater with LCT compared with ω-3 emulsions. Also, EPA and DHA together contributed proportionally much less than other fatty acids (<20%) to FFA released from ω-3 emulsions. In mixtures of LCT emulsion with ω-3 emulsions, the presence of >20% of w-3 particles substantially inhibited LCT emulsion hydrolysis (by up to 50%). Conclusions: Our results suggest that, during infusion of ω-3 emulsions, EPA and DHA may enter cells as TG or partial glycerides within emulsion particles and not as FFA and that coinfusion of ω-3 emulsion with LCT emulsion at low w-3:LCT emulsion ratios (up to 20% of total triglyceride as w-3) will not substantially inhibit LCT hydrolysis. (Journal of Parenteral and Enteral Nutrition 21:224-229, 1997)