Can Omega-3 Fatty Acids Lower Cholesterol and Triglycerides?

Some research has suggested that omega-3 fatty acids, found in fish, nuts, and supplements such as fish oil, might be able to help you lower your cholesterol and triglyceride levels. As "healthy fats," omega-3 fatty acids may also provide other heart-healthy benefits and even prevent cardiovascular disease.

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What Are Omega-3 Fatty Acids?

Omega-3 fatty acids are types of polyunsaturated fats found in fatty fish, plant-based sources, and certain supplements. These fats include:

  • Alpha-linolenic acid (ALA)
  • Docosahexaenoic acid (DHA)
  • Eicosapentaenoic acid (EPA)

ALA is available as a supplement and is found in a variety of plant products, including seeds (especially chia seeds and flaxseed), soybeans, and nuts.

EPA and DHA are commonly found in the following foods:

  • Fatty fish (anchovies, salmon, tuna, halibut, herring, and sardines)
  • Nuts (walnuts and almonds)
  • Supplements (fish oil, cod liver oil, and krill oil—these typically contain varying amounts of both EPA and DHA)

Omega-3s are referred to as “healthy fats” because they do not appear to promote atherosclerosis, known for causing heart disease. However, studies have primarily examined the effect that DHA and EPA have on the reduction of lipids and lowered risk of cardiovascular disease. ALA continues to be studied and might be less effective.

Do Omega-3s Affect Lipids?

DHA and EPA have been primarily studied when looking at the effect that omega-3 fats have on lipid levels. The usual doses of EPA and DHA used in these studies ranged between 250 milligrams (mg) and 500 mg to 5 grams per day. However, there is no recommended daily dose for either.

To achieve the amounts noted by researchers, you would need to consume a lot of fatty fish, nuts, seeds, and other foods containing these fats. Supplements can be used to bring more omega-3 fats into your diet and help achieve the target amount. Overall, omega-3 fats appear to have a favorable impact on your lipid levels.

Omega-3 fats have a notable effect on triglyceride levels:

  • One study showed that ingesting 900 mg of omega-3 fatty acids each day resulted in a 4% decrease in triglyceride levels after about six months.
  • The most effective dose of omega-3s used in most studies was between 2 and 4 grams. This resulted in a drop in triglycerides between 25% and 45%.
  • The effectiveness of omega-3 fatty acids on triglycerides appears to be dose-dependent. This means that the more omega-3 fatty acids ingested, the lower your triglyceride levels will fall.
  • Omega-3 fatty acids seem to affect recently ingested triglycerides and work best when following a healthy diet.
  • Individuals with extremely high triglyceride levels (greater than 500 mg/dL) appear to get the most benefit from omega-3 fatty acid supplementation.

Although EPA- and DHA-containing products can lower triglyceride levels, they may affect other parts of your lipid profile as well:

  • Omega-3 fats can slightly raise your low-density lipoprotein (LDL) cholesterol. This change, however, is modest and ranges from 3% to 10%.
  • Omega-3 fats—despite increasing your LDL—also increase the size of your LDL. Smaller LDL particles can increase your risk of developing atherosclerosis, whereas larger LDL particles are considered beneficial for your heart health.
  • Consuming omega-3 fatty acids also appears to slightly increase high-density lipoprotein (HDL) levels.

Not Necessarily a Cure-All

Fish oil may not be a cardiovascular event cure-all, according to a study published in JAMA and recently presented at the American Heart Association’s Scientific Sessions 2020. In the study, the researchers assessed omega-3 carboxylic acids or omega-3 CA (brand name Enova), a medication that is derived from fish oil.

The STRENGTH trial, which began in 2014, encompassed data from 13,078 adults at 675 centers in 22 countries.

All of the patients were being treated with statins and had known heart, brain, or leg artery blockages. They were at a higher risk for heart disease due to factors such as smoking and diabetes. The subjects either took the omega-3 CA medication or a placebo. The placebo used was corn oil.

The team compared the rates of cardiovascular death, heart attack, stroke, need for stenting or bypass surgery, and hospitalization for unstable angina in all of the study participants.

The study found that a combination of eicosatetraenoic acid (EPA) and docosahexaenoic acid (DHA)—omega-3 fatty acids found in certain fish—did not lower major cardiac events in high-risk patients.

The researchers found that 1,580 patients experienced at least one cardiac event. There were not any significant differences in cardiac event risk between participants in one group versus the other. However, the researchers did find that people taking the omega-3 CA medication developed atrial fibrillation (irregular heartbeat) more frequently than those who took corn oil.

The trial was stopped in January 2020 after researchers concluded that it likely would not prove the benefit of the omega-3 CA medication.

Fish Oil Research: Mixed Results

Other studies have also looked at fish oil and cardiovascular health. The evidence has been mixed, partly because researchers used different types and quantities of fish oils and different placebos.

  • The 2007 JELIS trial also evaluated the use of EPA and statins and found a reduction in non-fatal coronary events. Major coronary events were reduced slightly in those with a history of coronary artery disease. No placebo was used.
  • The 2019 VITAL study used supplements including vitamin D3 and omega-3 fatty acids. It showed fish oil didn’t lower the risk for major cardiac events.
  • The 2019 REDUCE-IT trial evaluated icosapent ethyl (brand name Vascepa), a high-dose pure EPA (a form of omega-3). The study included people with heart disease or people who were taking a statin medication with raised triglyceride levels. People on the omega-3 supplement had a 25% lower incidence of heart disease and stroke, and a 20% reduction in death from heart disease.

Heart-Healthy Benefits of Omega-3 Fats

Besides having a favorable effect on your lipid profile, omega-3 fats also have a positive impact on other aspects of your heart health:

  • Omega-3 fats appear to help keep your heart beating at a normal rate. This is important for patients at risk of a heart attack because arrhythmias are the leading cause of cardiac deaths in the United States.
  • Omega-3 fats may improve the function of blood vessels.
  • Omega-3 fats may lower blood pressure and heart rate.
  • Omega-3 fats may reduce inflammation at larger doses.
  • Studies have shown that individuals with cardiovascular disease who consume fish oil may have a decreased risk of sudden death and death due to cardiovascular disease.

Daily Intake

Omega-3 fatty acids are available in a variety of foods and supplements, including fish oil. Studies have found that the DHA and EPA found in fish oil can produce favorable changes in several risk factors for cardiovascular diseases, though fresh fish is more effective. 

Some experts, including the American Heart Association, recommend eating one to two servings of fatty fish per week. One serving consists of 3 1/2 ounces of cooked fish.

If you don't like eating fish, a fish oil supplement containing about 1 gram of omega-3 fats is an alternative. However, you should not increase your dose further without consulting with your healthcare provider. High doses of omega-3 fatty acids may affect blood platelet levels, causing a person to bleed and bruise more easily.

Prescription vs. OTC Supplements

Prescription omega-3 fatty acids contain a certain amount of natural or modified forms of omega-3 fatty acids. They are purified and are thoroughly rid of impurities such as trans-fats, mercury, or other contaminants.

Prescription omega-3 fatty acids are usually taken by individuals with very high triglyceride levels who are in need of larger doses of omega-3 fats to bring their triglycerides down.

Supplements that are available over-the-counter (OTC) are classified as “foods” by the U.S. Food and Drug Administration (FDA). Therefore, they do not have to undergo the rigorous purification processes or efficacy studies that prescription drugs have to go through.

A Word From Verywell

The evidence does show that incorporating omega-3 fatty acids into your diet can have a positive impact on your cholesterol levels. The best source is fresh fish and other foods that naturally contain these healthy fats.

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6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Preston Mason R. New insights into mechanisms of action for omega-3 fatty acids in atherothrombotic cardiovascular disease. Curr Atheroscler Rep. 2019;21(1):2. doi:10.1007/s11883-019-0762-1

  3. Agnostoni C, Bresson, JL, Fairweather-Tait S. Scientific Opinion on the Tolerable Upper Intake Level of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and docosapentaenoic acid (DPA)EFSA Journal. 2012;10(7):2815. doi: 10.2903/j.efsa.2012.2815

  4. Jain AP, Aggarwal KK, Zhang PY. Omega-3 fatty acids and cardiovascular disease. European Review for Medical and Pharmacological Sciences. 2015;19(3):441–445.

  5. Zibaeenezhad MJ, Ghavipisheh M, Attar A, Aslani A. Comparison of the effect of omega-3 supplements and fresh fish on lipid profile: A randomized, open-labeled trial. Nutr Diabetes. 2017;7(12):1. doi:10.1038/s41387-017-0007-8

  6. American Heart Association. Fish and omega-3 fatty acids. Updated March 23, 2017.

Additional Reading
  • American Heart Association. Fish and omega-3 fatty acids. 2017.

  • Dipiro JT, Talbert RL. Pharmacotherapy: A Pathophysiologic Approach. 10th ed. New York, NY: McGraw-Hill Education; 2017.