Determination of eicosapentaenoic acid and docosahexaenoic acid contents and the oxidation level of fish oil supplements from Bahrain market

Abstract

Eicosapentaenoic acid and docosahexaenoic acid are two types of omega-3 fatty acids that provide numerous health benefits. It is thus important to gain the recommended daily intake of eicosapentaenoic acid and docosahexaenoic acid and compensate for omega-3 deficiency through supplements. However, supplements are very susceptible to oxidation, which affects their biological significance. This study aimed to examine the quality of fourteen different commercially available fish oil supplements in Bahrain markets by comparing their actual and labelled Eicosapentaenoic acid and docosahexaenoic acid contents, determination of their oxidation levels by measuring the peroxide value, anisidine value, and the total oxidation value. Fish oils were methylated, separated, and identified by Gas Chromatography. Measurement of peroxide value was conducted using titration, and the anisidine value using spectrophotometry. The total oxidation value was calculated based on anisidine value and peroxide value values. Results showed that most brands have lower actual total fish oil per capsule than the labelled values. Only two brands (14.29%) showed an approximately similar amount of Eicosapentaenoic acid and docosahexaenoic acid, whereas six brands (42.86%) have a lower actual amount of both Eicosapentaenoic acid and docosahexaenoic acid. In addition, five brands (35.71%) have higher actual EPA and lower DHA values. Only one brand has higher actual amounts of both Eicosapentaenoic acid and docosahexaenoic acid. The results also showed that 57.1% of the tested supplements (8 out of 14) exceeded the recommended levels of peroxide value, while only one brand (7.14%) exceeded the safe levels of anisidine value. Moreover, five brands (35.71%) recorded a total oxidation value level higher than the recommended. Compared to other studies in several countries, the oxidative levels of supplements in Bahrain are not very high; nonetheless, it must be improved by applying oxidation levels regulations and storage regulations regarding fish oil supplements.

Keywords:

• Docosahexaenoic acid
• eicosapentaenoic acid
• fish oil
• oxidation
• supplements

Acknowledgements

The authors are grateful to the Department of Biology, College of Science, University of Bahrain where the study was conducted and financially supported.

Authors’ contributions

All authors have given substantial contributions to the conception or the design of the manuscript, including the acquisition, analysis, and interpretation of the data. All authors have participated in drafting the manuscript, and author Afnan Freije revised it critically. All authors read and approved the final version of the manuscript. All authors contributed equally to the manuscript and read and approved the final version of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).