Fish Oil for Heart Disease

The long standing notion that fish oil is the miracle food for a healthy heart was upturned rather unceremoniously when in 2015 the New York Times published an article entitled “Fish oil claims not supported by the research”. However, before rushing to toss all your fish oil or Omega-3 supplies down the toilet, let us take a closer look at how Omega-3s function.

It is now a commonly accepted fact that cardiovascular disease is rooted in inflammation. What is not known is which part of inflammation is the real culprit, as inflammation has two clear-cut phases. The first is called the initiation phase and involves the typical redness, swelling and pain we are all familiar with whereas the second phase known as resolution reverses the first phase and allows the tissue to revive. As long as the two phases are balanced, there is no problem. However, if the two phases are thrown out of balance for some reason, then the body reaches the status of low-level chronic inflammation, which is the basis for a large number of diseases including heart disease.

According to one study, for fish oil to have beneficial effects, high doses are required. At levels of less than 5 grams per day, fish oil is ineffective at inhibiting inflammation in the initiation phase.1 Almost no long term cardiovascular studies have ever made use of more than five grams of Omega-3 fatty acids on a daily basis. Furthermore, Omega-3 fatty acids work by actually speeding up inflammation’s resolution phase, provided doses even higher than five grams a day are used.2 The excessive amounts of Omega-3 consumption helps to formulate hormones known as resolvins, which work to promote the resolution phase of inflammation.

Another important factor that is necessary for maintaining the balance of initiation and resolution phases in the body is the Omega-6 to Omega-3 ratio. When a western diet is consumed, this ratio tends to be very high, which is why cardiovascular disease is prevalent in western societies. For there to be sufficient quantities of resolvin hormones in the body for chronic inflammation to be eliminated, this ratio must be around 1.5 ideally, but definitely less than 3. The higher this ratio is beyond 3, the greater the inflammation in the body.

The final important factor is, understanding the differences between the various types of Omega-3s. There are three important Omega-3s. Fish oil contains DHA or docosahexaenoic acid and EPA or eicosapentaenoic acid while the third type ALA or Alpha-linolenic acid comes from plant sources. The types of Omega-3s found in fish oil are the ones with the most established beneficial effects against heart disease. This is why fish oil supplements are given priority against heart disease.


  1. Endres S et al. “The effect of dietary supplementation with n-3 polyunsaturated acids on synthesis of interleukin-1 and tumor necrosis factor by mononuclear cells.” New Engl J Med 320:265-271 (1989)
  2. Serhan CN. “Pro-resolving lipid mediators are leads for resolution physiology.” 510:92-101 (2014)
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By Andy

Hi, my name is Dr. Andy Williams and I am a biologist with a keen interest in diet and nutrition. This site was set up to help me explore the research, facts and fiction about Krill Oil. Please feel free to contact me if you have any comments, questions or suggestions.

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