Omega-3 Fatty Acid Supplementation and ICU Length of Stay: A Critical Review of Current Evidence

Abstract

Omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) derived from fish oil, have been investigated for their role in modulating inflammation and immune function in critically ill patients in the intensive care unit (ICU). An exaggerated systemic inflammatory response in critical illness often leads to multiple organ dysfunction, nosocomial infections, and prolonged hospitalization. Omega-3 supplementation has been shown to suppress proinflammatory cytokine production, increase inflammatory resolution mediators, and support cellular energy metabolism. Evidence from controlled clinical trials and meta-analyses suggests that omega-3 supplementation, particularly via parenteral administration, may reduce ICU length of stay by an average of 2–3.5 days, reduce mechanical ventilation duration, and decrease infection rates. However, results are heterogeneous and vary with dose, route of administration, and patient characteristics. Notably, several trials in unselected ICU populations have yielded neutral or negative results, particularly with high-dose enteral omega-3 formulas. This review critically synthesizes the current evidence on omega-3 supplementation and ICU outcomes, discusses both supportive and non-supportive findings, and identifies gaps requiring further investigation.