Persistent organic pollutants in fish oil supplements on the Canadian market: polychlorinated biphenyls and organochlorine insecticides.

Rawn DF, Breakell K, Verigin V, Nicolidakis H, Sit D, Feeley M.

Sir Frederick Banting Research Centre, Tunney's Pasture, Ottawa, ON, Canada. TheaRawn@hc-sc.gc.c

Abstract

Fish and seal oil dietary supplements, marketed to be rich in omega-3 fatty acids, are frequently consumed by Canadians. Samples of these supplements (n = 30) were collected in Vancouver, Canada, between 2005 and 2007. All oil supplements were analyzed for polychlorinated biphenyls (PCBs) and organochlorine insecticides (OCs) and each sample was found to contain detectable residues. The highest SigmaPCB and SigmaDDT (1,1,1-trichloro-di-(4-chlorophenyl)ethane) concentrations (10400 ng/g and 3310 ng/g, respectively) were found in a shark oil sample while lowest levels were found in supplements prepared using mixed fish oils (anchovy, mackerel, and sardine) (0.711 ng SigmaPCB/g and 0.189 ng SigmaDDT/g). Mean SigmaPCB concentrations in oil supplements were 34.5, 24.2, 25.1, 95.3, 12.0, 5260, 321, and 519 ng/g in unidentified fish, mixed fish containing no salmon, mixed fish with salmon, salmon, vegetable with mixed fish, shark, menhaden (n = 1), and seal (n = 1), respectively. Maximum concentrations of the other OCs were generally observed in the seal oil. The hexachlorinated PCB congeners were the dominant contributors to SigmaPCB levels, while SigmaDDT was the greatest contributor to organochlorine levels. Intake estimates were made using maximum dosages on manufacturers' labels and results varied widely due to the large difference in residue concentrations obtained. Average SigmaPCB and SigmaDDT intakes were calculated to be 736 +/- 2840 ng/d and 304 +/- 948 ng/d, respectively.

Pubmed # 19200125

NOTE: Fish oils can vary in quality and also in dosage or percentage of omega 3 as EPA and DHA. There are other omega 3 fats. HIGHER or GREATER percentage of EPA and DHA means increased processing. While this sometimes may add a little more to purity, it DOES NOT EQUATE TO HIGHER QUALITY. The changes in structure may in fact lower the biological activity and desired pathways of natural fish oil. Regular fish oil is about 30% EPA and DHA. The first molecular distillation process usually doubles this amount to 60%. BUT, it changes the backbone of the fish oils from the natural glycerol to ethyl esters, which is ethanol alcohol. This may not be wise. ref Absorption of this form is reduced. Some studies reveal the natural triglyceride form has 33 to 48% greater absorption, plus it is less likely to oxidize than the ethyl ester form. An ethyl ester form of fatty acids at twice the dosage at the same price may not really be such a bargain.

PRICE AND POTENCY ARE POOR DETERMINANTS FOR FISH OIL CHOICES

There is a process to put the 60% EPA DHA fish oil back into a glycerol backbone which adds greater expense, but may increase biological value and affect absorption. Some companies are getting up to a 90% EDA and DHA percentage. This involves further separate processing with molecular distillation methods to FIRST get out the EPA and a second process to just separate out the remaining DHA. Higher purity and percentage, but at what price to the integrity of the fish oil structure?

Spoilage is also a major problem with fish oils. *****Always refrigerate your fish oils, even softgels, leave the cotton in bottle, plus get bottles that include desiccants. And buy smaller sizes. Never keep a bottle over 90 days. One 90% pure product was discovered to be highly spoiled. One krill oil was also found spoiled. There is more to picking the best format for fish oils than the products with the best marketing or price. Fish oils are large molecules and need antioxidant protection, and colder temperatures help stability.