Psoriasis and Essential Fatty Acids

Fish oil supplements are sometimes recommended for psoriasis treatment. The research evidence is contradictory, but because fish oil can have other health benefits (see article on Fish Oil), it might be worth trying.

Inflammation plays a role in psoriasis, and fish oil has also shown promise as an anti-inflammatory treatment.

Read more details about Essential Fatty Acids.

An 8-week, double-blind study followed 28 people with chronic psoriasis.¹ Half received 10 capsules of fish oil daily, and the other half received a placebo. By the end of the study, researchers saw significant improvement in itching, redness, and scaling, but not in the size of the psoriasis patches. However, another double-blind study followed 145 people with moderate to severe psoriasis for 4 months and found no benefit as compared to placebo.²

Typical dosages of fish oil are 3 g to 9 g daily, but this is not the upper limit.

Safety Issues

Fish oil appears to be generally safe. The most common problem is fishy burps. However, there are some safety concerns to consider.

For example, it has been suggested that some fish oil products contain excessive levels of toxic substances such as organochlorines and PCBs. ¹ If possible, try to purchase fish oil products certified not to contain significant levels of these contaminants. Note:Various types of fish contain mercury, but this has not been a problem with fish oil supplements, according to reports on Consumerlab.com.

Fish oil has a mild blood-thinning effect; ² in one case report, it increased the effect of the blood-thinning medication warfarin (Coumadin). ³ Fish oil does not seem to cause bleeding problems when it is taken by itself ⁴ or with aspirin. ⁵ Nonetheless, people who are at risk of bleeding complications for any reason should consult a physician before taking fish oil.

Fish oil does not appear to raise blood sugar levels in people with diabetes. ⁶ Nonetheless, if you have diabetes, you should not take any supplement except on the advice of a physician.

Fish oil may modestly increase weight and lower total cholesterol and HDL (“good”) cholesterol levels. ⁷ It may also raise the level of LDL ("bad") cholesterol; however, this effect may be short-lived. ⁸ If you decide to use cod liver oil as your fish oil supplement, make sure you do not exceed the safe maximum intake of vitamin A and vitamin D . These vitamins are fat soluble, which means that excess amounts tend to build up in your body, possibly reaching toxic levels. The official maximum daily intake of vitamin A is 3,000 mcg for pregnant women as well as other adults. Look at the bottle label to determine how much vitamin A you are receiving. (It is less likely that you will get enough vitamin D to produce toxic effects.)

Interactions You Should Know About

If you are taking warfarin (Coumadin) or heparin , do not take fish oil except on the advice of a physician.

1. Jacobs MN, Santillo D, Johnston PA, Wyatt CL, French MC. Organochlorine residues in fish oil dietary supplements: comparison with industrial grade oils. Chemosphere. 37(9-12):1709-21.
2. Emsley R, Niehaus DJ, Oosthuizen PP, Koen L, Ascott-Evans B, Chiliza B, van Rensburg SJ, Smit RM. Safety of the omega-3 fatty acid, eicosapentaenoic acid (EPA) in psychiatric patients: results from a randomized, placebo-controlled trial. Psychiatry Res. 161(3):284-91.
3. Buckley MS, Goff AD, Knapp WE. Fish oil interaction with warfarin. Ann Pharmacother. 38(1):50-2.
4. Harris WS. Dietary fish oil and blood lipids. Curr Opin Lipidol. 7(1):3-7.
5. Leaf A, Jorgensen MB, Jacobs AK, Cote G, Schoenfeld DA, Scheer J, Weiner BH, Slack JD, Kellett MA, Raizner AE. Do fish oils prevent restenosis after coronary angioplasty? Circulation. 90(5):2248-57.
6. Harris WS. Dietary fish oil and blood lipids. Curr Opin Lipidol. 7(1):3-7.
7. Emsley R, Niehaus DJ, Oosthuizen PP, Koen L, Ascott-Evans B, Chiliza B, van Rensburg SJ, Smit RM. Safety of the omega-3 fatty acid, eicosapentaenoic acid (EPA) in psychiatric patients: results from a randomized, placebo-controlled trial. Psychiatry Res. 161(3):284-91.
8. Cobiac L, Clifton PM, Abbey M, Belling GB, Nestel PJ. Lipid, lipoprotein, and hemostatic effects of fish vs fish-oil n-3 fatty acids in mildly hyperlipidemic males. Am J Clin Nutr. 53(5):1210-6.

1. Bittiner SB, Tucker WF, Cartwright I, et al. A double-blind, randomised, placebo-controlled trial of fish oil in psoriasis. Lancet. 1988;1:378-380.
2. Soyland E, Funk J, Rajka G, et al. Effect of dietary supplementation with very-long-chain n-3 fatty acids in patients with psoriasis. N Engl J Med. 1993;328:1812-1816.