Omega-3

Omega-3s are a group of essential fats that we need for normal metabolism and brain health. Because our bodies can’t make omega-3s, we have to consume them from food. Scientists are interested in omega-3s because they have anti-inflammatory effects, and may protect against heart disease, depression and inflammatory conditions1.

The best source of omega-3 is oily fish (like salmon, mackerel and herring) or fish oils, because they contain the long chain omega-3s that have the most direct health benefits. Shorter chain omega-3s are found in plant foods like walnuts and linseeds, but these don’t have the same beneficial effects2,3,4.     

What do we know about omega-3 and psoriasis?

Psoriasis is an inflammatory condition, triggered by the immune system. In people with psoriasis, the body overproduces hormones that cause inflammation.  These hormones are found in high levels in psoriatic skin 5,6, where they activate redness, itching and swelling. Experts also think these hormones might activate the overgrowth of skin cells.  

Since the 1980’s scientists have been interested in using omega-3 to treat psoriasis because omega-3 fats can slow down the release of these inflammatory hormones 2,7,5,6. 

Omega-3s also play a role in keeping our skin healthy. Omega-3s are found in the top layer of the skin, where they help maintain normal structure and protect against sun exposure and infection 8,9,7. They also control how much fluid our cells hold, keeping skin hydrated.

What does the science say?

Over the last 30 years there has been a lot of research into the effects of omega-3 in people with psoriasis. Many studies have found that omega-3 supplements can improve symptoms (like redness and itching), and reduce psoriasis severity.

In one study8, patients with psoriasis were given fish oil capsules containing 1.8 grams of EPA (a long chain omega-3) or the same number of capsules containing olive oil. After 8 weeks patients taking the fish oil capsules had less itching, redness and scaling than the olive oil group.

More recently9, patients with mild or moderate psoriasis were asked to take Tacalcitol (a type of vitamin D) or Tacalcitol plus 2 capsules of fish oil daily (containing 3.3 grams of omega-3) for 8 weeks. Although psoriasis improved in both groups, the group taking the omega-3 and Tacalcitol had greater improvements in itching, scaling and redness.

Other studies have also found that adding omega-3 supplements to existing treatments (like corticosteroids) can improve psoriasis more effectively than when a single treatment is used alone10,11.  One study also found psoriasis improved when people increased their omega-3 levels by eating more oily fish12.

Not all studies have shown positive results. Some found that omega-3 supplements made no difference effects to psoriasis severity or symptoms13,14.These differences might be explained by many factors. It could be that some of the studies were too short for the omega-3 to make a difference, because it can take many weeks for levels of omega-3 in the body to increase.

There are also big differences in the dose of omega-3 used in the studies. Some used small amounts9 (less than one gram) others used very high levels (12 grams)15. This makes comparing studies difficult.

Are there any risks associated with taking omega 3?

Omega-3 supplements are generally thought to be safe to use when taken in low doses. The Food and Drug Administration advises that adults can safely consume three grams per day of omega-3 per day.  

People who are taking medications that thin the blood should speak to their doctor before taking omega-3 supplements, as they may increase the risk of bleeding.  

Another way to increase omega-3 is to eat more oily fish. Most are safe to consume, but some types of fish contain high levels of contaminants (such as mercury and dioxins) that may be harmful if eaten in large amounts. Predator fish like marlin shark and swordfish contain the highest levels, whereas smaller fish like herring, sardines and anchovies contain much less.

Women who are pregnant or wanting to become pregnant should avoid marlin, shark and swordfish. All other adults should limit high mercury fish to one portion a week.  (For more advice on recommendations for pregnant women, click here).

How much omega 3 do I need?

It’s difficult to say how much omega 3 is needed to improve psoriasis, as studies have used different doses. Some research suggests a daily dose of 2 grams is needed to trigger anti-inflammatory effects, but smaller amounts might be helpful.  

100 grams of salmon or herring provides around 2 grams of omega-3, but other fish contain lower levels (click here for more information). If you’re not eating enough oily fish you can top up your intake with an omega-3 supplement.

Learning points

  • Omega-3s are a group of essential fats which may benefit psoriasis by reducing inflammation
  • We can’t make omega-3s, so we have to consume them from food. Oily fish and fish oil supplements are the best sources of omega-3
  • Some studies have found omega-3 supplements taken alone or with medication can help to reduce redness, itching and the amount of skin affected by psoriasis  
  • You can increase your omega-3 intake by eating more oily fish or taking a fish oil supplement

Sources

  1. Swanson D, Block R, Mousa S a. Omega-3 Fatty Acids EPA and DHA: Health Benefits Throughout Life. Adv. Nutr. An Int. Rev. J. 2012;3(1):1-7. doi:10.3945/an.111.000893.
  2. Deckelbaum RJ, Torrejon C. The omega-3 fatty acid nutritional landscape: health benefits and sources. J. Nutr. 2012;142(3):587S-591S. doi:10.3945/jn.111.148080.
  3. Simopoulos AP. Omega-3 fatty acids in inflammation and autoimmune diseases. J. Am. Coll. Nutr. 2002;21(6):495-505. doi:10.1080/07315724.2002.10719248.
  4. Burdge GC, Calder PC. Conversion of α -linolenic acid to longer-chain polyunsaturated fatty acids in human adults. Reprod. Nutr. Dev. 2005;45:581-597. doi:10.1051/rnd.
  5. Darlington LG. Do diets rich in polyunsaturated fatty acids affect disease activity in rheumatoid arthritis? 1988;(June 1987):169-172.
  6. Chapkin RS, Kim W, Lupton JR, McMurray DN. Dietary docosahexaenoic and eicosapentaenoic acid: emerging mediators of inflammation. Prostaglandins. Leukot. Essent. Fatty Acids 2009;81(2-3):187-91. doi:10.1016/j.plefa.2009.05.010.
  7. Sies H, Stahl W. Nutritional protection against skin damage from sunlight. Annu. Rev. Nutr. 2004;24:173-200. doi:10.1146/annurev.nutr.24.012003.132320.
  8. Bittiner SB, Tucker WF, Cartwright I, Bleehen SS. A double-blind, randomised, placebo-controlled trial of fish oil in psoriasis. Lancet 1988;1:378-380. Available at: http://onlinelibrary.wiley.com/o/cochrane/clcentral/articles/032/CN-00052032/frame.html.
  9. Balbás GM, Regaña MS, Millet PU. Study on the use of omega-3 fatty acids as a therapeutic supplement in treatment of psoriasis. Clin. Cosmet. Investig. Dermatol. 2011;4:73-7. doi:10.2147/CCID.S17220.
  10. Gupta AK, Ellis CN, Tellner DC, Anderson TF, Voorhees JJ. Double-blind, placebo-controlled study to evaluate the efficacy of fish oil and low-dose UVB in the treatment of psoriasis. Br. J. Dermatol. 1989;120:801-807. Available at: http://onlinelibrary.wiley.com/o/cochrane/clcentral/articles/539/CN-00061539/frame.html.
  11. Danno K, Sugie N. Combination therapy with low-dose etretinate and eicosapentaenoic acid for psoriasis vulgaris. J. Dermatol. 1998;25(11):703-5. Available at: http://www.ncbi.nlm.nih.gov/pubmed/9863281.
  12. Collier PM, Ursell A, Zaremba K, Payne CM, Staughton RC, Sanders T. Effect of regular consumption of oily fish compared with white fish on chronic plaque psoriasis. Eur. J. Clin. Nutr. 1993;47:251-254. Available at: http://onlinelibrary.wiley.com/o/cochrane/clcentral/articles/094/CN-00093094/frame.html.
  13. Bjorneboe A, Smith AK, Bjorneboe GE, Thune PO, Drevon CA. Effect of dietary supplementation with n-3 fatty acids on clinical manifestations of psoriasis. Br. J. Dermatol. 1988;118(1):77-83. Available at: http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=reference&D=med3&NEWS=N&AN=2829958.
  14. Gupta AK, Ellis CN, Goldfarb MT, Hamilton TA, Voorhees JJ. The Role of Fish Oil in Psoriasis. A Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Effect of Fish Oil and Topical Corticosteroid Therapy in Psoriasis.; 1990.
  15. Maurice PD, Allen BR, Barkley  a S, Cockbill SR, Stammers J, Bather PC. The effects of dietary supplementation with fish oil in patients with psoriasis. Br. J. Dermatol. 1987;117(5):599-606. Available at: http://www.ncbi.nlm.nih.gov/pubmed/3689678.
  16. P. M, H. G, F. G. n-3 fatty acids in psoriasis. Br. J. Nutr. 2002;87(SUPPL. 1):S77-S82. Available at: http://ovidsp.ovid.com/ovidweb.cgi?T=JS&PAGE=reference&D=emed5&NEWS=N&AN=2002059514.
  17. Bernstein AM, Ding EL, Willett WC, Rimm EB. A meta-analysis shows that docosahexaenoic acid from algal oil reduces serum triglycerides and increases HDL-cholesterol and LDL-cholesterol in persons without coronary heart disease. J. Nutr. 2012;142(1):99-104. doi:10.3945/jn.111.148973.

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