Parenteral Nutrition and Lipids

Abstract

Lipids have multiple physiological roles that are biologically vital. Soybean oil lipid emulsions have been the mainstay of parenteral nutrition lipid formulations for decades in North America. Utilizing intravenous lipid emulsions in parenteral nutrition has minimized the dependence on dextrose as a major source of nonprotein calories and prevents the clinical consequences of essential fatty acid deficiency. Emerging literature has indicated that there are benefits to utilizing alternative lipids such as olive/soy-based formulations, and combination lipids such as soy/MCT/olive/fish oil, compared with soybean based lipids, as they have less inflammatory properties, are immune modulating, have higher antioxidant content, decrease risk of cholestasis, and improve clinical outcomes in certain subgroups of patients. The objective of this article is to review the history of IVLE, their composition, the different generations of widely available IVLE, the variables to consider when selecting lipids, and the complications of IVLE and how to minimize them.

Lipid Use in Hospitalized Adults Requiring Parenteral Nutrition

“…In summary, lipid emulsions containing ω‐3 fatty acids offer a number of advantages in surgical patients. These include increased safety and tolerability, less inflammation, and a more hepatoprotective effect vs soybean oil emulsions . Moreover, lipid emulsions containing ω‐3 fatty acids can decrease the risk of cholestasis, as well as improve a number of clinical outcomes discussed previously (eg, decreased infections and decreased length of hospital/ICU stay) .…”

“…These include increased safety and tolerability, less inflammation, and a more hepatoprotective effect vs soybean oil emulsions . Moreover, lipid emulsions containing ω‐3 fatty acids can decrease the risk of cholestasis, as well as improve a number of clinical outcomes discussed previously (eg, decreased infections and decreased length of hospital/ICU stay) . In practice, the use of lipid emulsions containing ω‐3 fatty acids could eliminate the practice of withholding intravenous (soybean oil) lipid emulsions for some groups such as hyperdynamic patients (surgical and mixed ICU patients) and in stable patients with sepsis, and could decrease the incidence of hypertriglyceridemia and the resultant need to discontinue or decrease the supply of intravenous lipid emulsions.…”

“…Lipid emulsions are a principle part of parenteral nutrition, minimizing dependence on glucose as a major source of non‐protein energy and preventing essential fatty acid deficiency (EFAD) . Lipid oil sources can also be characterized by their relative range of inflammatory effects: soybean oil, which contains a high concentration of linoleic acid, is more inflammatory than either medium‐chain triglycerides (MCTs) or olive oil, while fish oil is even less inflammatory and possibly even anti‐inflammatory . Access to lipid emulsions is variable: ranging from a full spectrum of lipid emulsions available in parts of Europe, to the situation in the United States where pure soybean oil lipid emulsions were the only lipid emulsions available until August 2016 .…”

Summary of Proceedings and Expert Consensus Statements From the International Summit “Lipids in Parenteral Nutrition”

“…A wide variety of commercial lipid emulsions are now available for use in PN . Soybean oil is the traditional lipid source in IV lipid emulsions; however, based on concerns that an excessive supply of ω‐6 fatty acids might be associated with inflammatory and immunosuppressive effects, subsequent generations of lipid emulsions include lipids derived from alternative oil sources as well as composite lipid emulsions containing a mixture of lipids from different oil sources . Fish oil has become an important component of modern, composite lipid emulsions, owing in part to a growing body of evidence suggesting favorable effects on a variety of key biologic functions …”

“…The biological effects of lipid emulsions are strongly influenced by their fatty‐acid composition . Pure soybean‐oil emulsions contain high concentrations of the ω‐6 polyunsaturated fatty acid (PUFA) linoleic acid, which is converted to arachidonic acid, a precursor to eicosanoids that promote inflammation and suppress cell‐mediated immunity .…”