Intravenous Lipid Emulsions in Modern Parenteral Nutrition: A Comprehensive Analysis with a Focus on Olive Oil-Based Formulations

The Evolution and Biochemical Foundations of Intravenous Lipid Emulsions

From Energy Source to Therapeutic Modulator: A Historical Perspective

The concept of administering fats intravenously is not a modern one; initial attempts date back centuries, though these early efforts were often met with fatal outcomes, likely due to fat embolism resulting from unstable and unrefined preparations.[1] The modern era of intravenous lipid emulsion (ILE) therapy began in the 1960s with the development of the first stable emulsion derived from soybean oil. This first-generation ILE was a revolutionary advance, primarily aimed at achieving two fundamental goals: delivering a dense source of non-protein calories to malnourished patients and preventing the clinical manifestations of essential fatty acid deficiency (EFAD).[1]

For decades, these soybean oil-based long-chain triglyceride (LCT) emulsions were the standard of care. However, as clinical experience grew, a more nuanced understanding of fatty acid biochemistry emerged. Concerns began to mount regarding the potential adverse effects associated with the high load of omega-6 (ω-6) polyunsaturated fatty acids (PUFAs) inherent in soybean oil. A body of evidence suggested that an excess of ω-6 PUFAs could be pro-inflammatory and immunosuppressive, particularly in critically ill patients.[4] This recognition served as the primary catalyst for innovation, driving the development of second- and third-generation ILEs designed to mitigate these risks.