Fish oil supplements can be incredibly helpful for calming inflammation. For the greatest benefit, it is best to choose a good quality brand that takes steps to prevent the omega-3 oils from becoming oxidized.  Recommended products are:

• Nordic Naturals Ultimate Omega 2X.  (US) (UK) (CA)
•  Garden of Life Minami Platinum,

These fish oil supplements are relatively expensive, but they contain a larger amount of EPA and DHA than other brands, and the manufacturers go to great lengths to prevent oxidation of these fragile oils.  If you are choosing a different brand, the best way to ensure that the oils are not oxidized is to select a bottle that is at least 2 1/2 years from the expiration date, in soft-gel form, and in a dark bottle.

For children with juvenile arthritis or psoriasis, a good quality fish oil supplement that many kids are happy to take is Nordic Omega-3 Fishies.

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For more information on the evidence supporting fish oil supplements for psoriasis and arthritis, see the following excerpt from Chapter 8 of The Keystone Approach: 

Numerous double-blind, placebo-controlled studies have found a consistent benefit of fish oil supplements, particularly at relatively high doses (3–4 grams per day) and when taken for several months.[i] This benefit is seen in:

• psoriasis,[ii]
• rheumatoid arthritis,[iii]
• ankylosing spondylitis,[iv]
• Crohn’s disease,[v] and
• juvenile idiopathic arthritis.[vi]

Supplementing with additional fish oil has also been found to enhance the anti-inflammatory effect of a low-carbohydrate Mediterranean diet.[vii]

Despite decades of positive results in clinical trials,[viii] controversy has arisen in the past few years about whether supplements may do more harm than good on the basis that the omega-3 fats in fish oil are prone to oxidation.

Omega-3 fats are polyunsaturated, which means they are long-chain fats with many double bonds. These double bonds are inherently unstable. At each double bond, the fat molecule can be oxidized (by losing a hydrogen atom and ending up with a free radical), triggering chemical reactions that produce a variety of different compounds. Some of these compounds are inflammatory, theoretically undermining the anti-inflammatory effect of the fish oil.[ix]

Oxidation is more prevalent in fish oil than fish itself because oxidation occurs during processing and storage of the isolated oil. Investigations of the extent of this problem have yielded conflicting results; depending on the study, anywhere between 10 percent and 75 percent of fish oil supplements exceed oxidation limits.[x]

Given the prevalence of oxidation in fish oil, experts conclude that “it is likely that the omega-3 supplements used in many clinical trials have also been significantly oxidized.”[xi] Yet the results of these trials are overwhelmingly positive, particularly when high doses are given.[xii] Any oxidation that occurred to the fish oil supplements used in these studies therefore did not cancel out the therapeutic effects.

It is also worth noting that the average amount of oxidation products measured in fish oil supplements is comparable to that found in conventional cooking oils.[xiii] By eliminating these oils (discussed further below), it is possible to take fish oil supplements without adding to the overall burden of oxidized lipids. Indeed, studies adding a fish oil supplement in combination with a diet eliminating vegetable oils show the best results. In one such study, more than half of the patients had a moderate to excellent improvement in their psoriasis, while another 20 percent had a mild improvement.[xiv]

Fish oil supplements have been found to be helpful in the context of aggressive medical treatment of rheumatoid arthritis.[xv] In a study at the Royal Adelaide Hospital in Australia, patients taking a high-dose fish oil (5 grams of EPA and DHA per day) were twice as likely as those taking a low dose (0.4 g) to achieve remission while on “triple DMARD therapy” (methotrexate, sulphasalazine, and hydroxychloroquine). Fish oil supplements can therefore effectively complement conventional medical approaches.

The major advantage of fish oil supplements over just eating more fish is the ability to reach a high daily dose. It may take at least 3–4 grams per day of EPA and DHA to make a significant difference to psoriasis and arthritis,[xvi] which would require 5 to 6 ounces of high omega-3 fish every day. (In children with juvenile arthritis, a dose of 2 grams per day was effective.[xvii]) To meet the daily goal, it is probably easier in the long term to eat salmon, sardines, or mackerel a few times per week and add a daily fish oil supplement of 2–4 grams (2000–4000 mg).

We can also take steps to choose a fish oil supplement that is less likely to be oxidized. The most important factor seems to be the freshness of the supplement; in one study, almost all tested fish oil products that were more than 2½ years from expiration had low levels of oxidation.[xviii] Some other factors to consider when choosing a supplement:

• Light is a major contributor to oxidation during storage, so choose a product in a dark or opaque bottle.
• Krill oil has been found to have particularly high oxidation levels.[xix]
• Soft gels have lower levels of oxidation than bulk oil.[xx]
• Oils in triglyceride form are better absorbed than other forms.[xxi]
• If in doubt, cut open a capsule to smell and taste the oil. It should be only mildly fishy and not smell rancid.
• Look for a high concentration of EPA and DHA per capsule—at least 1000 mg.

One excellent choice is Nordic Naturals Ultimate Omega 2X. The company uses a proprietary oxygen-free manufacturing process to prevent oxidation and reports that the oxidation markers in their products are well below standard limits. Another good choice is Garden of Life Minami Platinum, which is produced using a carbon dioxide process to limit oxidation; the company also reports having independent lab verification of acceptable oxidation levels.

Like any supplement, check with your doctor before starting a fish oil supplement. There is some concern that it may increase bleeding risk in those taking blood-thinning medication.[xxii]

References

[i] Senftleber, N. K., Nielsen, S. M., Andersen, J. R., Bliddal, H., Tarp, S., Lauritzen, L., … & Christensen, R. (2017). Marine Oil Supplements for Arthritis Pain: A Systematic Review and Meta-Analysis of Randomized Trials. Nutrients, 9(1), 42.

[ii] Millsop, J. W., Bhatia, B. K., Debbaneh, M., Koo, J., & Liao, W. (2014). Diet and psoriasis, part III: role of nutritional supplements. Journal of the American Academy of Dermatology, 71(3), 561-569.

[iii] Miles, E. A., & Calder, P. C. (2012). Influence of marine n-3 polyunsaturated fatty acids on immune function and a systematic review of their effects on clinical outcomes in rheumatoid arthritis. British Journal of Nutrition, 107(S2), S171-S184.

[iv] Sundström, B., Stålnacke, K., Hagfors, L., & Johansson, G. (2006). Supplementation of omega‐3 fatty acids in patients with ankylosing spondylitis. Scandinavian journal of rheumatology, 35(5), 359-362.

[v] Belluzzi, A., Brignola, C., Campieri, M., Pera, A., Boschi, S., & Miglioli, M. (1996). Effect of an enteric-coated fish-oil preparation on relapses in Crohn’s disease. New England Journal of Medicine, 334(24), 1557-1560.

[vi] Gheita, T., Kamel, S., Helmy, N., El-Laithy, N., & Monir, A. (2012). Omega-3 fatty acids in juvenile idiopathic arthritis: effect on cytokines (IL-1 and TNF-α), disease activity and response criteria. Clinical rheumatology, 31(2), 363-366.

[vii] Paoli, A., Moro, T., Bosco, G., Bianco, A., Grimaldi, K. A., Camporesi, E., & Mangar, D. (2015). Effects of n-3 polyunsaturated fatty acids (ω-3) supplementation on some cardiovascular risk factors with a ketogenic Mediterranean diet. Marine drugs, 13(2), 996-1009.

[viii] Endres, S., Ghorbani, R., Kelley, V. E., Georgilis, K., Lonnemann, G., van der Meer, J. W., … & Schaefer, E. J. (1989). The effect of dietary supplementation with n—3 polyunsaturated fatty acids on the synthesis of interleukin-1 and tumor necrosis factor by mononuclear cells. New England Journal of Medicine, 320(5), 265-271.

[ix] Albert, B. B., Cameron-Smith, D., Hofman, P. L., & Cutfield, W. S. (2013). Oxidation of marine omega-3 supplements and human health. BioMed research international, 2013.

[x] Albert, B. B., Cameron-Smith, D., Hofman, P. L., & Cutfield, W. S. (2013). Oxidation of marine omega-3 supplements and human health. BioMed research international, 2013;

Albert, B. B., Derraik, J. G., Cameron-Smith, D., Hofman, P. L., Tumanov, S., Villas-Boas, S. G., … & Cutfield, W. S. (2015). Fish oil supplements in New Zealand are highly oxidised and do not meet label content of n-3 PUFA. Scientific reports, 5, 7928.

[xi] Albert, B. B., Cameron-Smith, D., Hofman, P. L., & Cutfield, W. S. (2013). Oxidation of marine omega-3 supplements and human health. BioMed research international, 2013;

Albert, B. B., Derraik, J. G., Cameron-Smith, D., Hofman, P. L., Tumanov, S., Villas-Boas, S. G., … & Cutfield, W. S. (2015). Fish oil supplements in New Zealand are highly oxidised and do not meet label content of n-3 PUFA. Scientific reports, 5, 7928.

[xii] Senftleber, N. K., Nielsen, S. M., Andersen, J. R., Bliddal, H., Tarp, S., Lauritzen, L., … & Christensen, R. (2017). Marine Oil Supplements for Arthritis Pain: A Systematic Review and Meta-Analysis of Randomized Trials. Nutrients, 9(1), 42.

Millsop, J. W., Bhatia, B. K., Debbaneh, M., Koo, J., & Liao, W. (2014). Diet and psoriasis, part III: role of nutritional supplements. Journal of the American Academy of Dermatology, 71(3), 561-569

[xiii] Halvorsen, B. L., & Blomhoff, R. (2011). Determination of lipid oxidation products in vegetable oils and marine omega-3 supplements. Food & nutrition research, 55.

[xiv] Kragballe, K., & Fogh, K. (1988). A low-fat diet supplemented with dietary fish oil (Max-EPA) results in improvement of psoriasis and in formation of leukotriene B5. Acta dermato-venereologica, 69(1), 23-28.

[xv] Proudman, S. M., James, M. J., Spargo, L. D., Metcalf, R. G., Sullivan, T. R., Rischmueller, M., … & Cleland, L. G. (2013). Fish oil in recent onset rheumatoid arthritis: a randomised, double-blind controlled trial within algorithm-based drug use. Annals of the rheumatic diseases, annrheumdis-2013.

[xvi] Cleland, L. G., James, M. J., & Proudman, S. M. (2005). Fish oil: what the prescriber needs to know. Arthritis research & therapy, 8(1), 202.

[xvii] Gheita, T., Kamel, S., Helmy, N., El-Laithy, N., & Monir, A. (2012). Omega-3 fatty acids in juvenile idiopathic arthritis: effect on cytokines (IL-1 and TNF-α), disease activity and response criteria. Clinical rheumatology, 31(2), 363-366.

[xviii] Halvorsen, B. L., & Blomhoff, R. (2011). Determination of lipid oxidation products in vegetable oils and marine omega-3 supplements. Food & nutrition research, 55.

[xix] Jackowski, S. A., Alvi, A. Z., Mirajkar, A., Imani, Z., Gamalevych, Y., Shaikh, N. A., & Jackowski, G. (2015). 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. Journal of nutritional science, 4, e30.

[xx] Jackowski, S. A., Alvi, A. Z., Mirajkar, A., Imani, Z., Gamalevych, Y., Shaikh, N. A., & Jackowski, G. (2015). 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. Journal of nutritional science, 4, e30.

[xxi] Dyerberg, J., Madsen, P., Møller, J. M., Aardestrup, I., & Schmidt, E. B. (2010). Bioavailability of marine n-3 fatty acid formulations. Prostaglandins, Leukotrienes and Essential Fatty Acids, 83(3), 137-141.

[xxii] Eritsland, J. (2000). Safety considerations of polyunsaturated fatty acids. The American journal of clinical nutrition, 71(1), 197S-201S.