Assessment of the safety of dietary fish oil supplements in terms of content and quality.

The fatty acid composition of top-selling fish oil dietary supplements in the markets was compared with the content stated on product label, and their oxidative qualities and heavy metal contents were evaluated in this study. While all the capsule groups (C) confirmed the label information, it was observed that one-third of the syrup groups (S) had less than the specified content. Capsule groups generally had richer EPA and DHA contents than syrup groups in the samples examined. The peroxide values (PV) of all fish oil capsules and syrups were found in the range of 1.97-2.89 mEq/kg and 2.22-18.30 mEq/kg, respectively. As for free fatty acids (FFA) values, the C4, S6, S9, and S10 groups were above the 3% oleic acid limit recommended for high-quality oils. However, thiobarbituric acid reactive substances (TBARs) values were found below 1 mg MA/kg in all groups. All fish oil supplements were within the limits specified in terms of As (0.50-4.19 µg/g), Cd (0.14 µg/g detected for one group, C5), Cu (not detected), Fe (0.32-15.7 µg/g), and Hg (≤ 0.1 µg/g). On the other hand, two fish oil supplements from the capsule group (0.17 for C6 and 1.01 µg/g for C8) and one group from the syrup group (0.29 µg/g for S10) exceeded the recommended limit in terms of Pb (0.1 mg/kg). As a result of the research, it can be concluded that the chemical quality of fish oils in syrup form needs to be improved and their reliability in terms of fatty acid content should be increased. Considering the heavy metals, it seems significant to follow up the fish oil products more strictly.