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Most health-care providers have heard of using omega-3 fatty acids, or fish oil, for supporting mental health. However, if you prescribe fish oil to your patients, they might not be getting the benefits that you would expect. While the idea sounds straightforward, in reality, the effective use of omega-3 fats can be somewhat complex. In the published research, omega-3 fatty acid supplements have often been found to have quality issues that could interfere with their efficacy.

Fish Oil Quality

Due to their chemical structure, omega-3 fatty acids are easily oxidized. When damaged through oxidation, they can lose their beneficial effects. One of the more recent analyses of commercial products was performed in the United Arab Emirates. The study found that 40% of commercial products off the shelf had oxidation levels above recommended limits (Jairoun 2020). A separate study from Australia discovered similar problems, finding that 38% of the 26 products tested exceeded recommended oxidation levels (Heller 2019).

A study from New Zealand on commercial fish oil supplements found even higher levels of oxidation with 92% of sampled products not meeting international guidelines (Albert 2015). Additionally, 70% of products had only two-thirds or less of the amount of omega-3 fatty acids as claimed on the product label. The evaluation of 171 commercial fish oil products available in Canada found that 50% were above recommended limits for oxidation (Jackowski 2015). A smaller study from the United States on three top-selling fish oil brands found that all three were above recommended oxidation levels (Mason 2017).

Other problems with fish oil products exist, including lack of purification and adulteration with cheaper oils. A study from Brazil discovered that two out of fifteen products tested contained high levels of soybean oil, a cheap “adulterant” (Galuch 2018). A study utilizing fish oil products purchased off the shelf in Italy found that one of the three products tested had not been purified properly (Nevigato 2021).

Verifying Quality Fish Oil Products

Based on the available evidence, it appears obvious that many fish oil products have significant quality issues. These issues could easily affect the results that individuals receive when consuming fish oil products. Arguably, the best way to verify the quality of a fish oil product is if the company in question has independent lab testing of randomly selected products off the shelf to verify omega-3 fatty acid quantities, oxidation status and contaminant levels.

Asking companies directly for documentation of an independent laboratory analysis of their products can be helpful. However, not all companies have their products evaluated. While some independent fish oil certifications exist, including IFOS and IVO, they rely on the manufacturer to send in samples for testing rather than testing fish oil off the shelf. While not ideal, it still may provide some information on the quality of available products for those that have been tested.

Learn the Latest Research in the Psychiatry Redefined Fellowship

Incorporating the latest research in functional and integrative medicine and mental health is a key component of what we teach in the Psychiatry Redefined Fellowship. The complexities of the research literature on omega-3 fats is a relevant example. In the fellowship, you will learn the latest research-based nutritional approaches for treating mental illness, and the different nuances of utilizing these approaches. The fellowship provides the tools for you to become a leader in Functional and Integrative mental health care.

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Albert BB, Derraik JG, Cameron-Smith D, et al. Fish oil supplements in New Zealand are highly oxidised and do not meet label content of n-3 PUFA [published correction appears in Sci Rep. 2016 Nov 07;6:35092]. Sci Rep. 2015;5:7928. Published 2015 Jan 21. doi:10.1038/srep07928

Galuch MB, Carbonera F, Magon TFS, da Silveira R, dos Santos PDS, Pizzo JS, Santos OO, Visentainer JV. Quality Assessment of Omega-3 Supplements Available in the Brazilian Market. J Brazl Chem Soc. 2018;29(3):631-638.

Heller M, Gemming L, Tung C, Grant R. Oxidation of fish oil supplements in Australia. Int J Food Sci Nutr. 2019;70(5):540-550. doi:10.1080/09637486.2018.1542666

Jackowski SA, Alvi AZ, Mirajkar A, et al. Oxidation levels of North American over-the-counter n-3 (omega-3) supplements and the influence of supplement formulation and delivery form on evaluating oxidative safety. J Nutr Sci. 2015;4:e30. Published 2015 Nov 4. doi:10.1017/jns.2015.21

Jairoun AA, Shahwan M, Zyoud SH. Fish oil supplements, oxidative status, and compliance behaviour: Regulatory challenges and opportunities. PLoS One. 2020 Dec 31;15(12):e0244688. doi: 10.1371/journal.pone.0244688. PMID: 33382790; PMCID: PMC7774961.

Kelaiditis CF, Gibson EL, Dyall SC. Effects of long-chain omega-3 polyunsaturated fatty acids on reducing anxiety and/or depression in adults; A systematic review and meta-analysis of randomised controlled trials. Prostaglandins Leukot Essent Fatty Acids. 2023;192:102572. doi:10.1016/j.plefa.2023.102572

Liao Y, Xie B, Zhang H, et al. Efficacy of omega-3 PUFAs in depression: A meta-analysis [published correction appears in Transl Psychiatry. 2021 Sep 7;11(1):465]. Transl Psychiatry. 2019;9(1):190. Published 2019 Aug 5. doi:10.1038/s41398-019-0515-5

Mason RP, Sherratt SCR. Omega-3 fatty acid fish oil dietary supplements contain saturated fats and oxidized lipids that may interfere with their intended biological benefits. Biochem Biophys Res Commun. 2017;483(1):425-429. doi:10.1016/j.bbrc.2016.12.127

Nevigato T, Masci M, Caproni R. Quality of Fish-Oil-Based Dietary Supplements Available on the Italian Market: A Preliminary Study. Molecules. 2021;26(16):5015. Published 2021 Aug 19. doi:10.3390/molecules26165015