What are these Omega-3s I keep hearing about?

food-712665_1280It seems like “omega-3” has become a bit of a buzz word. Whether folks are taking omega-3 supplements or eating fish for the omega-3s or buying eggs that advertise extra omega-3s, these nutrients are clearly on people’s health radars.  But, what are these omega-3 things exactly? And why should you care about them?

Without getting too deep into the biochemistry (something dietitians have to study in depth in our training!), we’ll provide an overview of omega-3 fatty acids, how they relate to health, and how you can make sure to get enough of them.

What are they?

Omega-3s or formally, omega-3 fatty acids, are basically a type of fat.  In fact, they are a family of polyunsaturated fats (a type of healthy fat that is typically liquid at room temperature; for example, olive oil contains a lot of polyunsaturated fats).

Omega-3s have a lot of different jobs in the body. The are:

  • part of cell membranes and affect the function of receptors in cell membranes
  • a key part of many different hormones involved in: regulating blood clotting, contraction and relaxation of artery walls, & inflammation
  • involved in the cellular regulation of genetic function, meaning they affect how genes are expressed in the body — this is likely why omega-3s have been linked to the prevention and control of several diseases.
  • essential for fetal development and healthy aging
  • found in concentrated amounts in the brain and retina

The body is very good at making many specific types of fats it needs from other fats taken in through the diet or that exist in the body. This isn’t true for omega-3s. They are necessary for humans, but we can’t make them. We must ingest them through diet or supplements, and for this reason they are known as essential fatty acids.

There are 3 primary omega-3 fatty acids:

(1) Eicosapentaenoic acid (EPA)

(2) Docosahexaenoic acid (DHA)

(3) Alpha-linolenic acid (ALA)

EPA and DHA are derived from fish and are responsible for many of the health benefits associated with omega-3s. ALA, however, is the most common omega-3 found in western diets and comes from land plants. It is generally used by the body for energy, although humans can convert a small amount of ALA into EPA and DHA.


What are the health benefits?

Omega-3s, specifically the EPA and DHA, have been linked to an array of health benefits including but not limited to:

  • Heart disease and stroke prevention
  • Improvement in autoimmune diseases such as lupus, eczema and rheumatoid arthritis
  • Possible protection against some cancers

What’s the evidence?

The evidence appears to be strongest for the possible heart disease benefit. Research has shown omega-3s can reduce the risk of arrhythmias, lower blood pressure and heart rate, improve blood vessel function, lower triglycerides, and reduce inflammation (which can play role in atherosclerosis). There is also good evidence to support the important role of DHA in pregnancy.  DHA supports fetal brain development and has recently been related to lower rates of asthma later in childhood.

What are the main sources of Omega-3s?

Omega-3s come from either (1) diet or (2) supplements.


EPA and DHA are sometimes referred to as the “marine omega-3s” because they are mainly found in cold-water, fatty fish like salmon, tuna, mackerel, lake trout and sardines as well as some other seafood products from algae and krill. ALA is mainly consumed in vegetable oils, nuts (walnuts especially), flaxseeds, leafy greens, and some animal fat (especially from grass-fed animals).

Because the main health benefits of omega-3s come from EPA and DHA and most of us already eat plenty of ALA in our Western diets, most dietary recommendations are geared towards eating more fatty fish.  The American Heart Association recommends eating 2 servings of 3.5 ounces of fish a week to meet omega-3 needs for most healthy individuals. Those with heart disease or other health conditions may benefit from higher amounts of EPA and DHA.


Fish oil supplements are the main source for supplemental EPA and DHA.  These can be a good option for a person who doesn’t eat cold-water, fatty fish on a weekly basis or who is trying to consume higher amounts determined by a doctor or dietitian due to specific health conditions. An array of supplements are available on the market with varying amounts of omega-3s.  When choosing a supplement its important to consider the following:

  • Dosage – Discuss with your health provider or dietitian the appropriate dose to meet your health goals.  This will take into account your dietary intake of EPA and DHA as well as any other medications or supplements you take. Higher doses of fish oil have a blood-thinning effect, and this can be dangerous for some people who are already taking blood thinning medications.
  • Brand reputation  – Supplements are not regulated in the US, making it very important to go with a well-known and respected brand that follows high purity standards. This is to ensure your supplement contains what it says it does and has minimal mercury. Some supplement companies pay to have an independent third-party verify the purity, quality, and potency of their supplements through testing.  The three main verification companies are USP, Consumer Lab, and NSF. Products that have undergone third-party testing will have a seal on their label from these verification companies. Labdoor also frequently releases quality and value rankings that can be helpful when choosing a supplement.
  • Amount of Omega-3s in one dose – The key numbers to look at on the label are the number of pills in one serving and the amount of EPA and DHA (in milligrams or mg) in one serving. It’s important to look for the EPA and DHA content as they are typically not listed on the front of the bottle, and they are NOT the same thing as the amount of fish oil advertised.  For example, the front of a supplement bottle may list that it has 2000 mg of fish oil in a serving of 2 pills, while the supplement facts label indicates this serving size contains  400 mg EPA and 200 mg DHA. Remember, the benefits come from the EPA and DHA, and you’ll want to choose a supplement that helps you reach the goal amount set with your healthcare provider, usually in the least amount of pills.


Bottom line: All three omega-3s are essential to humans, but most of us get way more ALA through our diet.  EPA and DHA are the most important of the omega-3s for health and many of us would benefit from increasing our intake.  We can do this by aiming to eat fatty fish a couple times a week and/or considering a fish oil supplement.

If you have questions or want to learn more, let the Transcend Nutrition Counseling dietitians help you optimize your intake of omega 3s.