Effects unrelated to anti-inflammation of lipid emulsions containing fish oil in parenteral nutrition for adult patients

Several reviews and meta-analyses on modulated inflammatory and immunologic responses after the administration of omega-3 polyunsaturated fatty acids (PUFAs) in different diseases and conditions have been published. However, omega-3 PUFAs exert several other actions which are not directly related to immunologic or inflammatory responses. The aim of this paper was to review the effects which are not directly related to immunologic and inflammatory responses of intravenous lipid emulsions (IVLEs) containing fish oil (FO) in parenteral nutrition (PN) for adult patients. IVLEs containing FO could have a role in the prevention of alterations in liver enzyme tests (LETs) or PN-associated liver disease (PNALD). Studies using FO doses of ≥ 0.150 mg/kg/day or IVLEs with high FO concentration reported more positive results than those with lower doses. Once PNALD was developed, the use of IVLEs exclusively composed of FO at doses of 0.25-1 g of FO/kg/day for several weeks could attenuate or even eradicate cholestasis and liver alteration. IVLEs containing FO seemed to have faster blood clearance, and this could be beneficial for some patients. Some studies also suggested a possible improvement of respiratory function by the administration of these IVLEs. In general, IVLEs containing FO were safe. Their use did not increase oxidative stress but, in contrast, increased plasma tocopherol content. They did not alter insulin sensitivity or glycemic control, and studies have found no relevant clinical effect on platelet aggregation or hemostasis. In conclusion, the use of IVLEs containing FO in PN may be beneficial with regard to older IVLEs, in addition to the modulation of systemic inflammation response.