Encapsulated fish oil products available in the UK meet regulatory guidelines with respect to EPA + DHA contents and oxidative status

Abstract

Encapsulated fish oil products continue to be of high interest, particularly concerning labelling claims and oxidative status. Thus, the present study analysed twenty‐three encapsulated fish oil products from the UK for their lipid and fatty acid composition as well as oxidation parameters. Oil contents ranged from 91.4‐118.9% of the manufacturers stated level. Lipid class analyses revealed three different types of oil products consisting of either triacylglycerol (TAG), ethyl ester (EE) or in combination (EE/TAG). Fatty acid profiles varied according to oil form with long‐chain omega‐3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), more concentrated in EE compared to TAG‐based oils with TAG/EE oils containing intermediary levels. Twelve products had EPA + DHA contents lower than advertised, although this was reduced to 11 when the actual measured capsule oil content was taken into consideration. All products had peroxide (PV) and anisidine values below those set by pharmacopeias, although four products had a PV above the industry set limit of 5 meq.kg−1. No relationships were found between oxidative parameters and missing EPA + DHA contents, although a significant relationship was observed between PV and days to expiry. In summary, encapsulated fish oil products on the UK market are not oxidized and meet regulatory guidelines with respect to EPA + DHA contents and oxidative status. Practical Applications: The study highlights the importance of quantifying the actual capsule oil content when determining EPA + DHA levels with respect to label claims. Furthermore, it also places results into context regarding regulatory guidelines demonstrating to regulatory bodies and consumers alike that UK fish oil products do meet specification and are not oxidised.