What are omega-3 fatty acids?

Omega-3 fatty acids are a major class of polyunsaturated fatty acids (PUFAs). PUFAs are different from saturated and monounsaturated fatty acids because they contain 2 or more double bonds in their carbon skeleton. The three main omega-3 fatty acids are alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).

Because the human body can’t form the double bonds needed to produce omega-3 fatty acids, they are considered essential and can only be obtained from the diet, especially ALA.1,3

Why are they important?

Omega-3s are important in the body because they make-up part of the phospholipids that form the structures of cell membranes. Omega-3s also provide energy for the body and are used to form signaling molecules that function in the body’s cardiovascular, pulmonary, immune, and endocrine systems.

A deficiency of essential fatty acids can cause rough, scaly skin, and dermatitis.

Some evidence shows that higher omega-3 levels are associated with a reduced risk of several chronic disease, including coronary heart disease.

Many observational studies have linked higher intakes of fish (high in omega-3s) with improved outcomes, but it’s difficult to pin point whether the benefits are due to the omega-3 content of the fish, other components of the seafood, the substitution of seafood for other less healthful foods, other health behaviours, or a combination1.

How much do I need?

For males ages 19 and up, Health Canada recommends at least 1.6 g/day of omega-3 fatty acids.

For females ages 19 and up, Health Canada recommends at least 1.1 g/day of omega-3 fatty acids.2

Sources of Omega-3s

  • Plant oils – flaxseed, soybean, and canola oils
  • Chia seeds
  • Walnuts
  • Some soy beverages are fortified with omega-3’s
  • Cold water fatty fish – salmon, mackerel, tuna, herring, sardines

Do I need an omega-3 supplement?

The use of dietary supplements containing omega-3s contributes to total omega-3 intakes. Fish oil is one of the most commonly used nonvitamin/nonmineral dietary supplements taken by adults and children. However, essential fatty acid deficiency in healthy individuals in North America is very rare.

However, it is recommended that no more than 3 g/day of EPA and DHA combined should be consume, including up to 2 g/day from dietary supplements. High doses of omega-3s can cause bleeding problems and possibly affect immune functions.

Side effects from taking omega-3 supplements include an unpleasant taste in the mouth, bad breath, heartburn, nausea, stomach discomfort, diarrhea, headache, and smelly sweat3.

Before taking omega-3 supplements, consult your physician.


  1. National Institutes of Health – Office of Dietary Supplements. (2019, October 17). Omega-3 Fatty Acids. Retrieved from https://ods-od-nih-gov.subzero.lib.uoguelph.ca/factsheets/Omega3FattyAcids-HealthProfessional/
  2. Health Canada. (2006, June 29). Dietary Reference Intakes. Retrieved from https://www.canada.ca/en/health-canada/services/food-nutrition/healthy-eating/dietary-reference-intakes/tables/reference-values-macronutrients-dietary-reference-intakes-tables-2005.html
  3. National Institutes of Health – Office of Dietary Supplements. (2019, July 11). Omega-3 Fatty Acids – Consumer Fact Sheet. Retrieved from https://ods-od-nih-gov.subzero.lib.uoguelph.ca/factsheets/Omega3FattyAcids-Consumer/

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