Fish oil emulsions: what benefits can they bring?

Recent advances indicate great potential for new fish oilcontaining lipid emulsions: the possible mechanisms involve suppression of excessive endothelial activity and thereby decreased production of pro-inflammatory mediators. This means that supplemental fish oil (n-3 fatty acids [FA]) may reduce inflammatory and thrombotic responses while protecting tissue microperfusion and immunity. Consequently, supplementation with fish oil might be used to improve standard clinical therapy, especially in chronic hyper-inflammatory diseases and as an adjunct therapeutic measure after trauma, injury, and during early sepsis. Encouraging effects with supplemental fish oil are observed in patients with chronic catabolism associated with cancer cachexia. Suppression of T-cell mediated immune function is an adverse effect with fish oil supplementation. This undesirable effect is partly due to increased lipid peroxidation and decreased antioxidant capacity and can be prevented by appropriate vitamin E supplementation. Parenteral administration of fish oil based emulsions might be advantageous compared to the enteral route because intestinal loss due to lipid remodelling is bypassed. A new type of emulsion made of a physical mixture of soybean-LCT, MCT, olive oil, and fish oil supplemented with vitamin E has been developed. This novel emulsion with reduced content of n-6 FA, high share of MUFAs and increased amount of n-3 FA is composed according to a current NIH recommendation. A randomized double blind clinical trial with the new emulsion revealed rapid incorporatiom of EPA and DHA in cell membranes resulting in a considerably decreased AA/EPA ratio. A profound increase of LTB5 and simultaneous decrease of LTB4 resulted in a marked decrease of the LTB 4/LTB5 ratio. TxB3 increased and TxB2 decreased. These changes are in accordance with the expected biochemical action of fish oil supplementation. We observed a 7 days shorter hospitalization with the new emulsion compared with the standard control LCT emulsion. The results suggest a beneficial immunomodulation probably due to parenteral provision of n-3 FA and olive oil and also because of the considerable reduction of n-6 FA and indicate that it is possible to establish fish oil supplementation protocols that provide maximum beneficial effects while adverse effects are minimized. Future studies need to be focussed on further elucidation of the intra and inter cellular signalling events mediated by n-3 FA. Understanding the molecular mechanism(s) modified by fish oils will ultimately lead to improved dietary strategies to aid the prevention of auto-immune disease, cardiovascular disease, certain type of cancer and to support therapeutical measures of trauma, sepsis and other acute illnesses. There is strong evidence that the future major feature in clinical nutrition in critically ill and chronic illness will be the creation of the optimum lipid emulsion for use in the most beneficial nutrient admixture. The fish oil story ‐ how it started