Ulcerative colitis (UC) causes inflammation and sores, called ulcers, in the inner lining of your colon. This can cause symptoms such as diarrhea and belly cramps. UC may also make it harder for your body to get the nutrients it needs. Certain medications and surgery can contribute to nutritional deficiencies as well.
Fish oil contains omega-3 fatty acids, which have anti-inflammatory properties. Although a few small, older studies suggested that fish oil might reduce inflammation in the colon, larger reviews have not found clear evidence that omega-3 supplements can induce or maintain UC remission. Current guidelines do not recommend them as a treatment for UC. Here’s what the research shows about fish oil and ulcerative colitis.
What Is Fish Oil?
Fish oil is an oil that contains omega-3 fatty acids and is available as a dietary supplement. Your body needs omega-3s for many functions, including cell growth, immune function, energy production, and muscle activity. Because your body can’t make these essential fatty acids, you need to get them from food or supplements.
There are three types of omega-3s:
- ALA (alpha-linolenic acid)
- DHA (docosahexaenoic acid)
- EPA (eicosapentaenoic acid)
Fish oil can be a good source of omega-3s and contains DHA and EPA. The fatty acid is known for its anti-inflammatory effects on your body, especially against specific conditions like heart disease, high blood pressure, cholesterol, and rheumatoid arthritis.
What Are the Benefits of Fish Oil for Ulcerative Colitis?
While there’s no cure for UC, growing research suggests that fish oil may help reduce or prevent inflammation in your colon. Not only this, but some studies claim omega-3s can also reduce the need to take anti-inflammatory drugs and promote healthy weight gain in people with UC.
How does it work? UC leads to an increase in leukotriene B4 levels in the innermost layers of the colon. It’s a type of chemical agent that triggers inflammation. High levels of it are associated with a more serious case of UC. Studies claim omega-3 fatty acids found in fish oil can reduce or prevent the rise in leukotriene B4, which lowers the inflammation in your gut.
A small study with 11 men with mild to moderate UC tested this. They were split into two groups. One group got fish oil for three months while the other got olive oil for three months. Then the groups switched treatments. The study found that those who got fish oil saw their UC symptoms improve by 56%. Moreover, eight men who were taking fish oil could reduce or stop taking anti-inflammatory drugs. However, the fish oil didn’t reduce leukotriene B4 levels in the colon.
Another small study saw similar results. In this study, several participants were able to cut down on their daily dose of prednisone, a steroid anti-inflammatory drug that can cause side effects, by up to 66%. Some experts believe that the EPA found in omega-3 fatty acids stops leukotriene B4 from causing a spike in inflammation levels, which then causes UC symptoms to improve.
But more research needs to be done to better understand if omega-3 fatty acids benefit UC and how much you might need to take for it to work.
Which Foods Are High in Omega-3 Fatty Acids?
Omega-3 fatty acids are naturally found in high levels in fatty fish. This includes:
- Herring
- Wild salmon
- Mackerel
- Sardines
- Anchovies
- Lake trout
- Striped bass
Fatty fish mostly contain DHA and EPA, and it’s the best way to get omega-3s into your body. To get the most out of your fish, you can either bake or broil it. But don’t fry it. You can also eat canned tuna, but watch out for high levels of mercury. Canned light tuna has less mercury than albacore, white, or yellowfin tuna. If you’re pregnant or nursing, avoid high-mercury fish such as swordfish, tilefish, and sharks.
Besides fish, there are other foods that contain omega-3s. If you’re vegan, vegetarian, or allergic to seafood, you can opt for plant-based sources, such as:
- Flaxseed oil
- Canola oil
- Chia seeds
- Walnuts
- Soy foods
- Pumpkin seeds
Plant-based omega-3s contain ALA. Your body has to convert this into DHA and EPA. Since this process isn’t the best way to get omega-3 fatty acids, you might have to eat more of it or supplement your diet with fish oil to meet the daily recommended amount.
Should You Take Fish Oil Supplements for Ulcerative Colitis?
It’s best to get your omega-3s directly from food for UC. If you’re unable to, taking fish oil supplements can boost your overall intake. But dosages can vary, and it does cause a few side effects. Before you start taking it, ask your doctor if fish oil supplements are right for you.
How Much Fish Oil Should You Include in Your Diet?
There’s no established omega-3 dose for ulcerative colitis. As a general guide, the Dietary Guidelines for Americans recommend about 8 ounces of seafood a week, or approximately two servings. This provides an average of roughly 250 milligrams of EPA and DHA per day.
Complications From Fish Oil
If you take the recommended amount of omega-3 fatty acids, it’s generally considered safe and good for your overall health. But supplements may cause mild side effects, such as:
- A fishy aftertaste
- Bad breath
- Heartburn
- Nausea
- Diarrhea
- Rash
Taking very high doses of omega-3s can increase the risk of bleeding and stroke. Omega-3s can also interact with some medications and foods, changing their overall effect.
These include:
- Anticoagulant (blood clotting) drugs or supplements
- Blood pressure medicine, herbs, or supplements
- Birth control drugs, which can interfere with the effects of fish oil
- Orlistat (Alli, Xenical), a type of weight loss drug that can lower fish oil absorption
- Vitamin E levels, which may dip when you take fish oil
If you have UC and you’re planning to include fish oil in your diet, check with your doctor if it’s right for you. If you’re allergic to seafood, experts aren’t sure if fish oil is safe for you. If you do take it, monitor for side effects, and if you have an allergic reaction, get immediate medical help.
Note that the FDA regulates supplements under a different set of regulations than it does drugs or food.
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