Can Omega-3 Fatty Acids Lower Your Cholesterol and Triglycerides?

Brian A. Jackson, istockphoto

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

  • DHA (docosahexaenoic acid)
  • EPA (eicosapentaenoic acid)
  • ALA (alpha linolenic acid)

ALA is available as a supplement, but can also be 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 – including anchovy, salmon, tuna, halibut, herring, sardines
  • Certain nuts – including walnuts and almonds
  • Supplements – including those labeled as fish oil, cod liver oil, and krill oil. These supplements will usually contain varying amounts of both EPA and DHA.

All three types of omega-3 fats are referred to as “healthy fats” because they do not appear to promote atherosclerosis associated with causing heart disease. However, more studies have examined the effect that DHA and EPA have on the reduction of lipids and lowered risk of cardiovascular disease. ALA has not been studied as much, and may be less effective.

How Do Omega-3s Affect Your Lipids?

DHA and EPA have been mostly 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 900 mg and 5 grams a day. In order to achieve this amount, you would need to consume a lot of fatty fish and other foods containing these fats.

Supplements can be used to supply the omega-3 fats in your diet – without having to consume a ton of fish, nuts and other foods to achieve this 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 to 4 grams - which resulted in a drop in triglycerides between 25 to 45%.
  • The effectiveness of omega-3 fatty acids on triglycerides appears to be dose-dependent - meaning that the more omega-3 fatty acids ingested, the lower that your triglyceride levels will fall.
  • Omega-3 fatty acids seemed to affect recently ingested triglycerides and worked 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, too:

  • Omega-3 fats can slightly raise your 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.
  • Taking omega-3 fatty acids also appears to slightly increase HDL levels.

Other, Heart-Healthy Benefits of Omega-3 Fats

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

  •  Omega-3 fats appear to help keep your heart beating at a normal rate. This is important for patients at risk of 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.
  • Studies have shown that omega-3 fats may lower blood pressure and heart rate.
  • Omega-3 fats may reduce inflammation at larger doses.
  • Previous studies have shown that individuals with cardiovascular disease consuming fish oil may have a decreased risk of sudden death and death due to cardiovascular disease.

What is the Difference Between Prescription Omega-3 Fatty Acids and Over-The-Counter 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. Supplements that are available over-the-counter are classified as “foods” by the Food and Drug Administration. Therefore, they do not have to undergo the rigorous purification processes or efficacy studies that prescription drugs have to go through. Prescription omega-3 fatty acids are usually taken by individuals with very high triglyceride levels who are in need to larger doses of omega-3 fats to bring their triglycerides down.

How Much Should I Take Each Day?

Omega-3 fatty acids are available in a variety of foods and supplements - including fish oil. Studies have found that that the DHA and EPA found in fish oil can produce favorable changes in several risk factors for cardiovascular diseases – such as improving your overall lipid profile and reducing the risk of death of cardiovascular disease and sudden death in some individuals.

Some experts, including the American Heart Association, recommend eating one to two servings of fatty fish per week. One serving consists of 3.5 ounces of cooked fish. If you don’t eat a lot of fish, a fish oil supplement containing about one gram of omega-3 fats may be considered. However, you should not increase your dose further without consulting with your healthcare provider. High doses of omega-3 fatty acids over 3 grams daily may affect your platelets, causing you to bleed and bruise more easily.


McKenney JM, Sica D. Prescription omega-3 fatty acids for the treatment of hypertriglyceridemia. Am J Health Syst Pharm.2007 Mar 15;64(6):595-605.

Balk EM, Lichtenstein AH, Chung M et al. Effects of omega-3 fatty acids on serum markers of cardiovascular disease risk: a systematic review. Atherosclerosis. 2006 Nov;189(1):19-30.

Dipiro JT, Talbert RL. Pharmacotherapy: A Pathophysiological Approach, 9th ed 2014

Minihane AM, Khan S, Leigh-Firbank EC, et al. ApoE polymorphism and fish oil supplementation in subjects with an atherogenic lipoprotein phenotype. Arterioscler Thromb Vasc Biol 2000; 20:1990

Griffin MD, Sanders TA, Davies IG, et al. Effects of altering the ratio of dietary n-6 to n-3 fatty acids on insulin sensitivity, lipoprotein size, and postprandial lipemia in men and postmenopausal women aged 45-70 y: the OPTILIP Study. Am J Clin Nutr 2006; 84:1290.

Wang C, Harris WS, Chung M, et al. n-3 Fatty acids from fish or fish-oil supplements, but not alpha-linolenic acid, benefit cardiovascular disease outcomes in primary- and secondary-prevention studies: a systematic review. Am J Clin Nutr 2006; 84:5.

Kris-Etherton PM, Harris WS, Appel LJ. Fish consumption, fish oil, omega-3 fatty acids, and cardiovascular disease. Circulation. 2002; 106:2747-2757.

American Heart Association. Fish and Omega-3 Fatty Acids. Link: Accessed May 23, 2016.

Continue Reading