Immunomodulatory and Anti-Inflammatory Potential of Shark Liver Oil: A Scoping Review of Human and Animal Studies.

Abstract

Shark liver oil (SLO) is commercially promoted as an immunity booster to fight off infections, heal wounds, and for its beneficial effects in cancer treatment. Despite the growing body of research on SLO, scattered data and reported outcomes in understanding its immunomodulatory and anti-inflammatory mechanisms exist across study designs and populations, and the experimental design variances complicate data interpretation for meaningful translation into clinical applications. This scoping review aims to address this by comprehensively charting human and animal models to identify patterns of immunomodulatory and anti-inflammatory effects of SLO and its bioactive components, thus highlighting areas requiring further investigation. A scoping search through Cochrane, PubMed^®, MEDLINE^® via Ovid and Scopus using keywords such as "shark liver oil", "immunomodulation", "anti-inflammatory", similar keywords and their combinations was performed. Quantitative and qualitative measurements of immune or inflammatory responses were recorded and mapped. A total of 16 articles met the inclusion criteria, including human studies and in vivo animal models with various baseline health conditions. SLO has a broad yet selective immunomodulatory effect that shows an adaptive response depending on context, such as inflammatory conditions, cancer, or infection. The inconsistencies in results highlighted the biological complexity and the context-dependent role of SLO in the immune system. Despite this, alkylglycerols (AKG) emerge as a key bioactive component, with some studies suggesting potential dose-dependent effects and exploring the structure-activity relationship of different AKG forms in modulating the immune response. Overall, the current evidence is promising but preliminary, with methodological differences in the literature that highlight a clear need for rigorous, standardized clinical trials.