Fish Oil - What You Need to Know

Health Benefits of Fish Oil

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What Is Fish Oil?

Fish oil, used as a dietary supplement, is derived from cold-water fish (mackerel, salmon, tuna, herring, halibut, cod). Fish oil contains omega-3 fatty acids (DHA and EPA) that reduce inflammation. DHA is docosahexaenoic acid and EPA is eicosapentaenoic acid. Fish oil is known to lower triglycerides, lower blood pressure, and have a protective effect against heart disease -- among other health benefits.

Health Conditions That May Benefit From Fish Oil Supplementation

Fish oil is thought to reduce morning stiffness and inflammation. It is used to treat rheumatoid arthritis, lupus, psoriasis, Raynaud's phenomenon, and depression -- though effectiveness has not been established for all of these conditions. It also may play a role in brain function.

Fish Oil Studies

According to the Primer on the Rheumatic Diseases, nine studies of rheumatoid arthritis patients taking omega-3 showed fewer tender joints, but there was no apparent reduction in joint damage. Six studies showed that rheumatoid arthritis patients taking fish oil were able to lower their dose of NSAIDs or corticosteroids.

Availability of Fish Oil

Fish oil is available by eating fish, of course, but also as capsules or chewable tablets. The capsules are large. If you have difficulty swallowing pills, fish oil can be a challenge.

It's difficult to eat enough fish to achieve a therapeutic effect, so fish oil capsules that are at least 30% EPA/DHA are recommended for arthritis and related conditions.

The Primer recommends the following doses:

  • rheumatoid arthritis - up to 2.6 grams fish oil (1.6 g. EPA) twice a day
  • lupus and psoriasis - 2 grams EPA/DHA three times a day
  • Raynaud's phenomenon - 1 gram four times a day

Warnings About Fish Oil

Fish oil may increase the risk of bleeding when taken at high doses, especially when taken with other drugs that also increase the risk of bleeding (e.g., NSAIDs, blood thinners).

Discuss your medication regimen with your doctor before adding fish oil supplements.

Bottom Line

When choosing fish oil supplements, look for reputable brand names. Look for products that contain fish oil without mercury.


Fish Oil. Primer on the Rheumatic Diseases. Thirteenth edition.
Published by the Arthritis Foundation. Accessed July 31, 2009.

Omega-3 fatty acids, fish oil, alpha-linolenic acid. MedlinePlus. March 1, 2008.

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