Fish Oil

Reviewed by: HU Medical Review Board | Last reviewed: August 2023

Inflammatory bowel disease (IBD) is a condition of chronic inflammation of the digestive tract. The two main forms of IBD are Crohn’s disease (CD) and ulcerative colitis (UC). Symptoms related to IBD include abdominal pain, diarrhea, nausea and fatigue. A major part of treating IBD revolves around managing its symptoms. Medications such as aminosalicylates, immunomodulators, corticosteroids, antibiotics, and biologic therapies are the most important part of therapy and are the only treatments that have been scientifically proven to be effective in treating the underlying disease.

Some people with IBD also choose to take additional supplements, such as fish oil. While some people may find supplements like fish oil to be beneficial to their health, sufficient research has not yet been completed to determine how supplements work, or if they work at all, and how they may benefit people with IBD.1

As with any form of complimentary or alternative medicine, it is important to use these alternative supplements under the supervision of a qualified healthcare provider. IBD varies widely based on the individual. While fish oil supplementation may have an effect for some people, it may not have an effect for others. In addition, some supplements can interact with prescription medications, and it's important for your doctor to understand all medications and supplements you are taking.

By providing your email address, you are agreeing to our Privacy Policy and Terms of Use.

What is fish oil?

Fish oil is a dietary supplement derived from fish.2,3 Fish oil contains omega-3 fatty acids which is one of the essential fatty acids in the human diet, along with omega-6 and omega-9. Our bodies do not make omega-3 fatty acid, so it must be obtained through food. Omega-3 fatty acids are thought to be important in promoting critical brain function. Some studies have suggested that they can help reduce the risk of heart disease, reduce inflammation in the body, reduce blood pressure in people with hypertension, and reduce cholesterol.2

Omega-3 fatty acids can be obtained through some foods such as fatty fish (salmon, herring, mackerel), some nuts and some green vegetables.1,2

How might fish oil affect the symptoms of IBD?

Studies regarding fish oil supplementation and CD symptoms have yielded conflicting findings.1,3 Omega-3 fatty acids, found in fish oils, are believed to reduce inflammation. This could be a beneficial side effect for patients suffering from IBD, because the disease causes inflammation of the digestive tract. If the omega-3 fatty acids in fish oil possibly have some effect on inflammation, then it is possible that it may also reduce some symptoms that IBD inflammation causes.

While some small studies have suggested that fish oil supplementation may help people with IBD maintain remission, the studies have not yet been replicated in large groups of people with IBD. Other studies have not shown any benefit of taking fish oil in people with IBD.1,3

Where can I get fish oil supplements?

Omega-3 fatty acid can be supplemented by regularly ingesting fish oil. Fish oil typically comes in capsule form, but it can also be purchased as a pure liquid. Both forms can be found at most drug stores and health food stores.2 It is important to be sure the supplements are made by a reputable company that certifies their products are free of heavy metals, which are toxic in large amounts. Patients should consult with their healthcare providers regarding dosage for fish oil supplementation.

In addition, fish oil can be consumed by eating fish. Health professionals recommend baking or broiling, rather than frying.2

What are the possible risks of fish oil supplementation?

High doses of omega-3 fatty acids may be harmful, resulting in increased bleeding risk and might suppress the immune system.2 Some patients have reported symptoms such as abdominal pain and diarrhea as a result of fish oil supplementation. Fish oil supplementation should only be administered under the supervision of a healthcare provider. As with any medicinal treatment, alert your healthcare provider of any medications or supplements you are taking, as certain drugs could have adverse interactions.