Will Krill Oil Reduce Your Risk of Heart Disease?

Could fish oil reduce your risk of heart disease? This question has been puzzling scientists for decades. Some studies have shown benefit, while others have been inconclusive (Circulation, April 11, 2017). If you do decide to take fish oil, we recommend a high-quality product that is not rancid. Other people have wondered whether krill oil might be a better choice.

Is Krill Oil Safe?

Q. For several years I had been taking krill oil, as supposedly it had the benefits of fish oil but was more potent. At a recent check-up, my doctor told me that I should stop taking it.

According to him, recent findings show that fish oil does not have the health benefits that were ascribed to it, but it does increase the risk of stroke and heart attack.

This is the first I’d heard this. I’ve stopped my supplementation, but I would like to know if this is really the new consensus.

A. Most research supports the cardiovascular benefits of a diet rich in fish and other sources of omega-3 fats (Nutrients, Oct. 26, 2023). After decades of research, the benefits of fish oil supplementation is still a bit controversial. However, the overall picture appears to show that fish oil can help prevent cardiovascular outcomes, including heart attack and stroke (Progress in Cardiovascular Diseases, May-June 2024).

Scientists have not studied krill oil as carefully as fish oil. However, it too is a rich source of omega-3 fatty acids. Many researchers believe it would be as helpful as fish oil.

How Often Is Fish Oil Rancid?

The Food and Drug Administration does not monitor dietary supplements for quality. Therefore, consumers must be vigilant.

A study published in the Journal of Dietary Supplements reveals the problem with this lack of oversight. Millions of people take supplements of omega-3 fatty acids. These products are frequently derived from fish, krill or algae. They are thought to provide anti-inflammatory health benefits, including the possibility that they reduce your risk of heart disease.

High Levels of Oxidation:

Scientists from George Washington University and ConsumerLab.com evaluated 72 popular brands of omega-3 supplements (Journal of Dietary Supplements, Sept. 15, 2023). The researchers used three different measures to detect oxidation, also known as rancidity. Nearly two-thirds of the flavored supplements were overly oxidized. Roughly 13% of the unflavored pills also failed the tests for rancidity. This is likely to diminish the health benefits of these supplements. The authors suggest exercising caution, especially when it comes to flavored fish oil. Flavoring may sometimes mask the “off” odor of a rancid product.

Does Fish Oil Reduce Your Risk of Heart Disease?

The BMJ published a study analyzing data from the UK Biobank (The BMJ, March 4, 2020). The results should help clarify how well fish oil could reduce your risk of heart disease.

What Did the Scientists Find Out About Fish Oil and the Risk of Heart Disease?

Approximately 427,000 men and women between 40 and 69 years old filled out questionnaires between 2006 and 2010. About a third of them reported taking fish oil supplements on a regular basis.

Those who took the supplements were 13 percent less likely to die during the follow-up period. They were also 7 percent less likely to have heart attacks and 16 percent less likely to die from cardiovascular causes.

Other Benefits from Fish Oil Supplements:

This is far from the first study to indicate that fish oil may reduce your risk of heart disease. We heard earlier from a reader wondering about supplements.

Q. I’ve taken fish oil successfully for years for lupus, osteoarthritis, dry eye, and cardiovascular benefits. Three different specialists recommended it. Even if they changed their minds about it tomorrow, their updated opinion wouldn’t alter my opinion on the benefits of fish oil.

I’ve found that quality matters for fish oil, as it does in many things in life. The amount and ratio of EPA and DHA are also important.

How Do Quality Fish Oil Supplements Affect Health?

A. A recent review of three large randomized controlled trials concluded that marine omega-3 fats (fish oil) can reduce the risk of cardiac complications and death from cardiovascular causes (Mayo Clinic Proceedings, Oct. 15, 2019).  One of these trials (REDUCE-IT) used a prescription pharmaceutical EPA product, Vascepa.

To summarize, the authors of this analysis concluded that

“Marine omega-3s should be used in high doses for patients with CHD on statins who have elevated triglycerides and at about 1 gram/day for primary prevention for individuals who do not consume at least 1.5 fish or seafood meals per week.”

A different meta-analysis published in the Journal of the American Heart Association (Oct. 1, 2019) also concluded that fish oil supplements can reduce the risk of heart attacks and death from cardiovascular disease. In the thirteen trials analyzed here, higher doses of quality fish oil were linked to more protection.

Autoimmune Conditions Like Lupus or Rheumatoid Arthritis:

In addition, there is evidence that omega 3 fats have potential in treating autoimmune diseases like yours (Frontiers in Immunology, Sept. 27, 2019). Although your joint pain is caused by osteoarthritis, quality fish oil has beneficial effects in rheumatoid arthritis (Nutrition, Jan. 2018).

Dry Eye Disorder:

You mentioned that fish oil helps ease your dry eyes. A systematic review of 15 studies suggests that supplements with omega-3 fatty acids may improve symptoms of dry eyes (Acta Ophthalmologica, Dec. 2017). While the scientific evidence is not perfect, it makes sense for you to continue with something that appears to be helping you.

How Can You Find Quality Fish Oil Supplements?

A few of the studies included in these analyses used pharmaceutical-grade fish oil, including icosapent ethyl (Vascepa) as mentioned above and omega-3 acid ethyl esters (Lovaza). The downside of these prescription products is price.

Learn More:

You can learn more about improving risk factors in our eGuide to Cholesterol Control and Heart Health.  People taking fish or krill oil should consult their health care providers.

If your physician does not prescribe one of these prescription quality fish oil supplements, you will want to choose carefully at the drugstore or online. We like to consult ConsumerLab.com when we contemplate an important supplement purchase. In one analysis (Feb. 2020), the organization found that Kirkland Signature Fish Oil 1000 mg was a top pick. Another brand that it rated highly is Minami Garden of Life Platinum Omega-3 Fish Oil Orange Flavor. For more information on these and other fish oil supplements, you may wish to purchase the report from ConsumerLab.com.