fish oils

What are fish oils?

Fish oils are oils found in the tissues of fish. They contain a certain type of fat called omega-3.


What are omega-3 fats?

Omega-3 fats are a type of fat that may be important for good general health. Our bodies cannot produce omega-3 fats so they must be obtained from food. Omega-3 fats are mostly found in oily fish and certain nut and seed oils.


Omega-3 fats may help reduce inflammation in some forms of arthritis. Make sure you take the right dose to affect inflammation.


How do omega-3 fats work for arthritis?

Certain types of omega-3 fats can reduce inflammation from psoriatic arthritis (PsA). This may help to relieve joint pain and stiffness in a similar way to non-steroidal anti-inflammatory drugs (NSAIDs).


Can omega-3 fats be beneficial for people with PsA? 

Omega-3 fats have not been studied in all forms of arthritis. Current research suggests omega-3 fats are helpful for people with inflammatory arthritis, including PsA. 

The use of fish oils has been shown to improve the symptoms of PsA, like reducing joint tenderness and stiffness.  These effects may be further enhanced by limiting intake of polyunsaturated oils (e.g., corn, soybean, safflower, and sunflower) to 10 grams or less per day.  Fish oils have also been shown to improve symptoms of psoriasis, including skin reddening, itching, scaling and inflammation. 


Other benefits

Long-term intake of fish oil has been shown to reduce the reliance on NSAIDs. This can help decrease the risk of side effects from these medicines. Fish oils can also help reduce the risk of heart disease and heart attack. Evidence suggests fish oils play a role in preventing and treating depression.


Where do I find omega-3 fats?

  • Oily fish, such as tuna, salmon, herring, sardines and mackerel
  • Flaxseed (linseed) and canola oil (however these oils are not as active against inflammation as fish oils)
  • Walnuts
  • Foods fortified with omega-3, such as margarines and eggs.


Eating foods rich in omega-3 fats may help you to achieve benefits for your heart and general health. However it is unlikely that you can obtain enough omega-3 fats from your diet to reduce inflammation without also taking fish oil supplements.


Where do I find fish oil supplements?

There are many different brands of fish oils supplements available at health food shops and pharmacies.


What type of supplement should I choose?

Fish oil supplements are available as capsules or as a liquid. Different brands of capsules vary in the amount of omega-3 fats they contain so it is worthwhile to compare brands. Check the label to see the amount of omega-3 contained in each capsule (it may be listed as a total omega-3 or as EPA and DHA, which are two forms of omega-3). Bottled fish oil is generally the most convenient and least expensive way to take the dose needed to reduce inflammation (see below). Capsules are preferred by some people and are more portable when travelling.


Should I take fish oil or krill oil?

Nearly all of the information about omega-3 fats and arthritis has come from studies of fish oils. To date, there is very little evidence to show whether krill oil is useful for arthritis.


What dose should I take for arthritis?

Research suggests the dose needed to reduce joint inflammation is 2.7 grams of omega-3 (EPA plus DHA) daily. This dose usually requires approximately either:

  • nine to 14 standard 1000mg fish oil capsules or five to seven capsules of a fish oil concentrate per day, or
  • 15mL of bottled fish oil or five to seven mL of concentrated bottled fish oil per day.

(Note, fish oil can benefit your heart and general health at lower doses. However these doses, generally, will not control symptoms of arthritis).


How long will it take to notice an effect?

You may need to take fish oil supplements regularly at the recommended dose for two to three months before you notice improvements in your arthritis symptoms. If there is no change by then, the supplements are probably not effective for your PsA.


Are there any side effects?

Fish oil is usually well tolerated. A possible side effect from fish oil supplements is a mildly upset stomach (for example, heartburn, nausea, diarrhoea). There is currently no evidence that fish oils increase the risk of bleeding or interact with medicines that affect bleeding, such as aspirin or warfarin. Despite this, it is recommended that you consult with your doctor before having major surgery or if you are commencing fish oil while taking warfarin. International Normalised Ratio (INR) monitoring tests (blood tests to check how long it takes for your blood to clot) may be done more often at first, to ensure there are no side effects. If there is any bleeding, stop taking fish oils and consult with your doctor.


Caution with fish liver oils

It is important not to confuse fish oils with fish liver oils (such as cod liver oil and halibut liver oil). Fish liver oils also contain vitamin A. Large amounts of vitamin A can cause serious side effects, particularly during pregnancy. If you take fish liver oils in the doses recommended for arthritis you may exceed the recommended daily intake of vitamin A. Only take the dose of fish liver oil recommended on the label. To increase your intake of omega-3 fats, you should do so by taking pure fish oils, not fish liver oils.


Let your doctor know

Always let your doctor and pharmacist know if you are taking any treatments, including fish oils and other natural medicines. Do not stop any current treatments without first discussing it with your doctor.