Composition and Functionality of Lipid Emulsions in Parenteral Nutrition: Examining Evidence in Clinical Applications

Abstract

Lipid emulsions (LEs), an integral component in parenteral nutrition (PN) feeding, have shifted from the primary aim of delivering non-protein calories and essential fatty acids to defined therapeutic outcomes such as reducing inflammation, and improving metabolic and clinical outcomes. Use of LEs in PN for surgical and critically ill patients is particularly well established, and there is enough literature assigning therapeutic and adverse effects to specific LEs. This narrative review contrarily puts into perspective the fatty acid compositional (FAC) nature of LE formulations, and discusses clinical applications and outcomes according to the biological function and structural functionality of fatty acids and co-factors such as phytosterols, a-tocopherol, emulsifiers and vitamin K. In addition to soybean oil-based LEs, this review covers clinical studies using the alternate LEs that incorporates physical mixtures combining medium-and long-chain triglycerides or structured triglycerides or the unusual olive oil or fish oil. The Jaded score was applied to assess the quality of these studies, and we report outcomes categorized as per immuno-inflammatory, nutritional, clinical, and cellular level FAC changes. It appears that the FAC nature of LEs is the primary determinant of desired clinical outcomes, and we conclude that one type of LE alone cannot be uniformly applied to patient care.

Synthesis of middle–long–middle structured intralipids by biological catalysis and the evaluation of intralipids’ protective effect on liver injury rats

“…The specific structure of MLM‐based intralipids placed different fatty acids on specific positions of triglyceride to deploy their best advantages. MCFAs were placed in sn ‐1,3 position, which would be hydrolyzed to provide fast energy for liver regeneration (Karupaiah & Sundram, 2007; Sadu Singh et al., 2020). LCFAs were placed in the sn ‐2 position, which will be absorbed in the form of monoglyceride form, and it can cross the cell membrane faster than the free form of LCFA (Bracco, 1994).…”

Effects of Dietary n–3 and n–6 Polyunsaturated Fatty Acids in Inflammation and Cancerogenesis

“…The third generation LE consists of 20% soybean oil and 80% olive oil. The fourth generation of LE are enriched by fish oil [38,39]. Some research suggests that phytosterols, a component of soy lipid emulsions, are a major health-complicating factor.…”

Intravenous Lipid Emulsions in the Prevention and Treatment of Liver Disease in Intestinal Failure

“…The progress made by 1974 allowed for administration of customized “all-in-one” solutions, the so-called “3-in-1” PN solutions with amino acids, dextrose and customized electrolytes [ 17 ]. The observation that soybean-based emulsions had a negative impact on cellular immune function prompted the development of initially two oil and later three and four oil-based lipid emulsions [ 11 , 18 , 19 ].…”