Make sure your omega-3 supplements work for you | True Grace Blog

Make sure your omega-3 supplements work for you

Make sure your omega-3 supplements work for you

By Kristina Jackson, True Grace Science & Agriculture Board member & Director of Research at OmegaQuant Analytics

The only way to truly know is to test.

As an omega-3 researcher and registered dietitian, one of the questions I get asked the most is: “How much and what kind of fish oil should I take?”

I always answer this question with more questions:

  • How much fish do you usually eat? What kind?
  • Do you take an omega-3 or fish oil supplement?
  • Do you know how much eicosapentaenoic acid and docosahexaenoic acid (EPA and DHA) is in that?
  • Do you know your Omega-3 Index?

Most people may be able to answer the diet questions, but they have no idea what the Omega-3 Index is, much less what their level is.

 What’s the Omega-3 Index? 

The Omega-3 Index is the amount of the marine omega-3 fatty acids EPA and DHA in red blood cell membranes. The Omega-3 Index was proposed by Dr. William Harris and Dr. Clemens von Schacky in 2004 as a risk factor for heart disease, as well as a stable measure of omega-3 intake.[1] A low or undesirable level is 4% or less (EPA and DHA over total membrane fatty acids), and the desirable range is 8 to 12%.

Over 40 years of research, higher omega-3 blood levels have been linked to longer life, less risk of death from heart attack, lower risk of preterm birth, improved muscle and joint health, better cognitive function, lower risk of depression and anxiety, and more.[2] This laundry list may seem too good to be true, but every cell in the human body has omega-3 fatty acids in its cell walls. So not having enough omega-3s can affect many different areas of health.

The omega-3 level in red blood cells—i.e., the Omega-3 Index—reflects the levels found in heart, muscle, liver, and most other tissues, except the brain and eyes. The brain and eyes have the highest concentrations of omega-3s and are harder to change after development.

What do omega-3s do in the body?

Omega-3s in cell membranes are somewhat bulky, which actually makes the membranes more fluid and flexible. Cells, tissues, and vessels all function better when they are more flexible (to a point).

Omega-3s are also involved in reducing inflammation and supporting healing after an inflammatory event. Enzymes use omega-3s to produce potent molecules that help heal the body after inflammation occurs (protectins, resolvins, maresins, and other eicosanoids). If there aren’t enough omega-3s in the cell membranes, there will be less healing to balance the inflammatory molecules the body creates. Chronic inflammation is a core piece of most diseases. 

There are many other mechanisms that omega-3s are involved in (and likely many more that we have not discovered yet), but membrane fluidity and pro-resolving actions are core to their healthfulness.

How—and how much—should you supplement?

To answer this question, I’d ideally have your Omega-3 Index tested so I could provide a personalized dose of EPA and DHA that would be enough to get you to the 8 to 12% range. Start by talking to a registered dietician or healthcare provider, and if you’d like to test your Omega-3 Index, visit  

At OmegaQuant, we’ve found that 70% of people who report supplementing with omega-3s still don’t have Omega-3 Index levels in the desirable zone because they aren’t getting enough (or they’re not getting their omega-3s in the right form). We have also found that, on average, someone who is a 4% Omega-3 Index (which is typical of a non-fish-eating person in the US) would need 1500 to 2200 mg per day of EPA and DHA to reach 8% in 4 months. However, that’s just the average; some people will need more and some less.

Another aspect of fish oils that can affect absorption is the form the omega-3s are in: triglyceride, phospholipid, and ethyl ester forms are the most common. Ethyl ester forms, which are quite common as high-concentrate fish oils, can be less well absorbed than the other kinds, especially if taken on an empty stomach . Triglyceride and phospholipid forms of omega-3s are absorbed on average 10% better than ethyl esters, when both are taken with food. This means you usually need less EPA and DHA when they are in these two forms compared to the ethyl ester form. These two forms are also found naturally in fish, which may be why they are better absorbed. Unfortunately, it can be difficult to find out what kind of form omega-3s are in on supplement labels as it's not required to be on the label. Usually, triglyceride and phospholipid forms are advertised as such, so if you don't see that on the label, assume it's an ethyl ester form. 

Knowing your Omega-3 Index level, the dose of EPA and DHA in your supplement, and the form of those omega-3s are the main factors in designing a successful supplementation strategy. 

What about diet?

In nature, EPA and DHA are found only in fish and other seafood, so eating fish is another way to reach higher omega-3 blood levels. However, only people who regularly eat fish at least 3 times per week have a decent chance of having an Omega-3 Index of 8%, based on OmegaQuant research. Pescatarians and people from cultures with high fish intake, like Japan, can have a high Omega-3 Index without supplementation.

You may have heard you can get another kind of omega-3, alpha-linolenic acid (ALA), from plant-based foods like walnuts, chia, and flaxseeds. These are very healthy foods, but eating more of them will not do much to raise blood levels of the other omega-3s, EPA and DHA.

Test, then test again

Testing, trying something for 3 to 4 months, and re-testing is the best way to figure out if your supplements or dietary choices are working for you. In the case of the Omega-3 Index, if you aren’t at 8% after 6 months of trying to increase your omega-3 intake, then you need to change your dosage or supplement or fish choices. But once you know what works for you, you can test less frequently (once per year) to make sure you are staying on track.

Dr. Kristina Jackson, PhD, RD, is a registered dietitian specializing in omega-3 essential fatty acids who has helped develop tests for expecting and new moms to measure their levels of omega-3s.


[1] The Omega-3 Index: a new risk factor for death from coronary heart disease? - PubMed (

[2] Publications | OmegaQuant

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