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Natural Health Products

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Fish oil

Common Name(s)

fish oil, fish oil fatty acids, omega-3 fatty acids, cod liver oil, salmon oil, tuna fish oil

Scientific Name(s)

Fish oil

General Information

Fish oil contains essential fatty acids, which are important for proper structure and function of cells in our body. This type of dietary fat is considered to be healthy because they contain unsaturated fatty acids instead of the not-so-healthy saturated fatty acids found in animal fat. Omega-3 fatty acid is a type of unsaturated fatty acid that contains DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid).

How is this product usually used?

Fish oils can be obtained from eating fish (e.g., anchovies, sardines, mackerel, herring, tuna, salmon, halibut, cod liver) or by taking supplements. These supplements are taken orallyorallyto be taken by mouth (swallowed) and may come in various forms, including capsules, liquid, tablets, and powders. The dosage ranges from about 100 mg to 3,000 mg of fish oil (EPA plus DHA) per day, depending on age and what it is being used for. The maximum daily intake of this product for children between the ages of 1 to 8, 9 to 13, and 14 to 18 are 1,500 mg, 2,000 mg, and 2,500 mg, respectively.

Products containing 100 mg to 3,000 mg of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) per daily intake are used as sources of omega-3 fatty acids, EPA, DHA for the maintenance of good health, and help support cognitivecognitiverelating to the ability to think, reason, remember, and discern health or brain function.

Products containing 150 mg to 2,000 mg of EPA and DHA (with at least 150 mg DHA) per day can be used to help support brain, eyes, and nerves development in children under 12 years of age.

Products containing 500 mg to 3,000 mg of EPA and DHA with a ratio of EPA to DHA between 0.5:1 and 2:1 can be used to help to maintain or support cardiovascular health, reduce serum triglycerides or triacylglycerols, and reduce the pain of rheumatoid arthritis.

Products containing 1,500 mg to 2,000 mg of EPA and DHA (with at least 1,000 mg EPA) per day and a ratio of EPA to DHA of 1.75:1 to 2:1 can be used to help promote healthy mood balance.

What is this product used for?

Fish oils containing DHA and EPA have been used for different purposes, including:

  • maintaining overall good health
  • maintaining and supporting cardiovascular health (e.g., heart disease, heart attack)
  • lowering a type of fat in your body called triglycerides
  • reducing the pain and stiffness related to rheumatoid arthritis in adults (when used in combination with conventional therapy)
  • helping support brain and cognitivecognitiverelating to the ability to think, reason, remember, and discern function (e.g., attention deficit hyperactivity disorder, Alzheimer's disease)
  • helping support the normal development of eyes, brains, and nerves in children and adolescents
  • helping promote healthy mood balance

Your health care provider may have recommended this product for other conditions. Contact a health care provider if you have questions.

What else should I be aware of?

Studies have shown that fish oil can lower triglyceride levels by 20% to 50%, but it may not work as well as some of the prescription medications that are available. It is important to ask your doctor or pharmacist if this supplement is right for you before starting it.

An analysis of all studies with omega-3 fatty acids showed that it lowers the risk of death and heart attack resulting in death. A similar review, however, concluded that omega-3 fatty acids did not affect rates of death or other events including heart attack, heart failure, or stroke. The second review included poorly-designed trials as well as studies of ALA (alpha linolenic acid, which came from plant sources), so it may have led to different results. Overall, there is good evidence to support the use of omega-3 fatty acids, especially DHA and EPA, to prevent heart disease.

Some studies have shown that fish oil can possibly help with symptoms (e.g., morning stiffness) common in people with rheumatoid arthritis.

Research to date did not show that fish oil is beneficial to prevent cognitivecognitiverelating to the ability to think, reason, remember, and discern function decline in seniors, though fish oils may help slow the progression of mild Alzheimer's disease. They may also help improve symptoms in children with ADHD.

The American Heart Association and Health Canada recommend eating fish (particularly fatty fish) at least 2 times a week. Depending on what you are using fish oil for, the amount of fish oil that you need may vary, so always check with a health care professional first.

Fish oil is generally well-tolerated. The most common side effects include belching, bad breath, heartburn, nausea, and diarrhea. Some of these stomach side effects can be avoided by taking fish oil with food.

High doses of fish oil can slow blood clotting. When it is taken with other medications that can affect your body's ability to clot blood, fish oil can increase the chance of bleeding.

Fish oil should likely be avoided in patients who are allergic to fish and seafood, as well as those who have severe liver disease, bipolar disorder, or people with an implantable defibrillator (a device used to prevent irregular heartbeat).

There may be an interaction between fish oils and the following medications:

  • blood pressure lowering medications
  • "blood thinning" medications (e.g., warfarin, clopidogrel, ASA)
  • birth control pills
  • orlistat

Before taking any new medications, including natural health products, speak to your physician, pharmacist, or other health care provider. Tell your health care provider about any natural health products you may be taking.


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  3. Fish Oil (monograph). Natural Medicines Comprehensive Database. (Accessed online 1 October 2008)
  4. Health Canada. Licensed Natural Health Products database. Fish Oil. (accessed 28 May, 2010)
  5. Bucher HC, Hengstler P, Schindler C et al. N-3 polyunsaturated fatty acids in coronary heart disease. A meta-analysis of randomized controlled trials. Am J Med 2002;112:298-304.
  6. Hooper L, Thompson RL, Harrison RA et al. Omega 3 fatty acids for prevention and treatment of cardiovascular disease. The Cochrane Database of Systematic Reviews 2004.
  7. American Heart Association. Fish and omega-3 fatty acids., accessed September 16, 2008.
  8. Health Canada. Eating well with Canada's Food Guide: Meat & Alternatives. (Accessed 1 October 2008)

All material © 1996-2015 MediResource Inc. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.