You may have seen in the news this week an article about fish oils and concerns regarding quality.  We received the following from one of our suppliers (FxMed) …. Our clinic supplies quality, usually practitioner only, supplements.  The following may help bring a more balanced view of  issues surrounding fish oils.  Rancidity is an issue we are always concerned about and we would encourage you to purchase your fish oils from us or another reputable practitioner.

“FxMed is concerned for patients and practitioners with respect to the results from research conducted by the University of Auckland’s Liggins Institute evaluating the quality and content of fish oils sold in New Zealand.

The study looked specifically at the amount of omega-3 EPA and DHA contained in various products, measuring the oxidation (rancidity) of the oil by measuring Peroxide, Anisidine and Totox Values. The conclusion was that there is a high number of fish oils sold in NZ that do not meet label claims with regards to omega-3 content (specifically EPA and DHA) probably due to the high rancidity or oxidation levels causing degradation of the EPA and DHA molecules.

Similar international research has generally shown that most fish oils meet their active ingredient list, so further investigation is needed in relation to the research. It does seem unlikely that such a high percentage of products would fall so far under their label claim. No information has been released on which products or brands were included in the study.

GOED (Global Organisation for EPA and DHA Omega-3’s) consulted with fatty acid experts about this study and some of their concerns follow:  

  • Only three of the 32 oils tested contained a quantity of EPA + DHA that was equal to or higher than that claimed by the label, with more than two-thirds of supplements containing less than 67%. Because of the consistency of the results, it seems likely that the authors were using a method that yields incomplete results. The authors did disclose their method and did not follow the accepted AOCS, European Pharmacopeia, or GOED Voluntary Monograph methods, although it is unclear whether the authors’ method was validated.
  • The authors’ statement that “oxidation may at least in part account for the low n-3 PUFA levels” suggests a lack of general knowledge of lipid analysis. The amount of n-3 PUFA lost to the oxidation implied by high pAV (Anisidine Value) and PV (Peroxide Value) is too low to be picked up by FAME analysis.
  • If flavoured oils were analyzed, this would have been problematic because many flavors contain aldehydes that interfere with pAV testing.
  • According to the authors, “A 12ml sample of oil was produced by combining the contents of 8–24 capsules (depending on capsule size). From this pooled oil sample, PV, AV, Totox, and fatty acid concentration were measured in triplicate.” It’s important to know that the analyses must be done immediately before the oils oxidize. The data reported in Table 1 in the study appears to have been generated by someone with limited experience handling n-3 PUFA oils. Typically, you see much higher AVs than PVs, but in the case of the oils reported in line 15 (Canada), 25 (Australia) and 32 (New Zealand), this is reversed, which suggests poor handling of the oil. Generally, high PVs suggest the oils were oxidized upon opening the capsule.

Due to the suspicious nature of the results, GOED has decided that its next round of randomized testing of currently marketed products will be selected exclusively from the New Zealand market. Once GOED has the results, it intends to share them with the Therapeutic Goods Administration (TGA) in Australia and Medsafe in New Zealand. In addition, The Omega-3 Centre in Australia has been leading a media outreach effort to ensure that some balance is included in the reporting on the issue”.