Oxidation in EPA‐ and DHA‐rich oils: an overview

Abstract

Oxidation of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) rich omega-3 oils (hereafter referred to as either EPA and DHA or omega-3) is a complicated topic, but an important one to understand. A significant number of consumers cite fishy burp and/or taste, thought to be the result of oxidation, as one of the main reasons they do not consume EPA and DHA rich oils. In addition, consumers note that some articles have raised concerns about the potential for adverse effects associated with consumption of oxidized oils. Measuring oxidation in omega-3 oils is complicated due to the differences in chemical and physical characteristics of many commercially available products, which means not all methods to determine quality are appropriate for all types of oils. A number of consumer advocacy groups, product quality seal programs and academic groups have published data on levels of oxidation in omega-3 oils. Overall, this data shows that commercially available omega-3 supplements are low in oxidation. If consumers have a poor sensory experience with their omega-3 product, they should try another product as an alternative.

Australian and New Zealand Fish Oil Products in 2016 Meet Label Omega-3 Claims and Are Not Oxidized

“…Anisidine value met international recommended level, for 8 of the 10 products. Products 3 and 10 (pAV 108, 109 respectively) were known to contain flavorings that interfere with the pAV test [11]. …”

“…GOED is currently finalising their fatty acid results, which have also generally shown compliance [15], and it intends to share them with the industry and the regulators. GOED recently published a review on the topic of oxidation of EPA and DHA rich oils [11]. For over 2000 published analyses of fish oil capsules included in the review, 2171/2187 products analysed were compliant for PV, with 2092/2117 products compliant for pAV, both with respect to Australian Government, British Pharmacopoeia and European Pharmacopeia standards.…”

“…For over 2000 published analyses of fish oil capsules included in the review, 2171/2187 products analysed were compliant for PV, with 2092/2117 products compliant for pAV, both with respect to Australian Government, British Pharmacopoeia and European Pharmacopeia standards. GOED also stated the use of TOTOX as a measure of oxidation (a calculation combining PV and pAV) was not valid for any oils containing other interfering ingredients (many oils are flavoured) or that have strong colours, including krill oils and virgin salmon oils [11]. In recognition of the methods issues that are recognized to occur, GOED and the Council for Responsible Nutrition (CRN) published and widely distributed a White paper [16] prior to the completion of the peer review scientific paper [11].…”

“…A number of organizations and consumer groups issue seals for product quality seals, and academic groups have published data on levels of oxidation in omega-3 oils. Overall, these data show that commercially available omega-3 supplements are low in oxidation products [11]. The White paper prepared by GOED and the CRN responds to the methods issues widely recognized to have occurred in the New Zealand fish oils study and a further recent and similar Canadian study [17].…”

Encapsulated Fish Oil Products Available in the UK Meet Regulatory Guidelines With Respect to EPA + DHA Contents and Oxidative Status

“…Consequently, the oxidative status of oils can be evaluated through several methods such as measuring the peroxide value (PV) and para ‐anisidine value ( p ‐AV), among others, as primary and secondary oxidative products, respectively. Industry regulators, including the British and European Pharmacopeias, have limits for n‐3 LC‐PUFA‐containing oils at 10 meq kg −1 for PV, 30 for p ‐AV, and 50 for the total oxidation value (TOTOX), a combination of both PV and p ‐AV to give an assessment of total oxidation . The Global Organization for EPA and DHA omega‐3s (GOED), on the other hand, an industry association body commonly representing fish oil manufacturers, have set their own more stringent limits for n‐3 LC‐PUFA oils, through a Voluntary Monograph of 5 meq kg −1 , 20, and 26 for PV, p ‐AV, and TOTOX, respectively, as a means of maintaining products of high quality …”