Fish oil and cod liver as safe and healthy food supplements

OBJECTIVES: The aim of this study is to determine the content of mercury, methylmercury and persistent organic pollutants in the capsules filled with fish oil from marine fish and in the canned cod liver and find out, whether analyse products are safe and suitable for human consumption. METHODS: Total mercury was determined by cold vapour atomic absorption spectroscopy on an AMA-254 (Altec Ltd., Czech Republic) single-purpose mercury analyzer. Methylmercury in the cod liver in the form of chlorid methylmercury was determined by gas chromatography. Seven indicator congeners of PCB (PCB 28, 52, 101, 118, 138, 153, 180), HCH, HCB, DDT and its degradation products DDE and DDD, were determined by gas chromatography-mass spectrometry. RESULTS: In capsules filled with fish oil (n=19) total Hg levels were in the range of 0.013 to 2.03 ng/g. All the capsule oil samples analyzed for MeHg were below the detection limit. The highest concentration of total Hg was found in cod liver - can A (0.223 ng/g). The maximum percentage of MeHg in total Hg concentration was found in a liver sample - can B. The values of alpha-, beta-, gamma-, delta- HCH and of HCB were found below the detection limits in all the capsule samples analyzed. In eight capsules, the presence of highly lipophilic PCB congeners was demonstrated. DDT and its important DDE metabolite were found in ten samples. In canned cod liver the highest concentration of all PCB congeners was demonstrated in can D. The lowest congener concentrations, however, were found in smoked cod liver - can C. DDT with its main metabolite DDE was detected in can C. No additional DDT and DDD persistent pollutants were detected. CONCLUSIONS: The consumption of fish oil in capsules, and canned cod liver is safe and healthy and should be encouraged.