Life Extension Magazine®

Older couple feeling good after supplementing with fish oil

How Fish Oil Benefits Heart Disease Patients with Depression

Recently published studies provide clear evidence that omega-3 fatty acids in fish oil provide protection against heart disease and depression by reducing inflammation throughout the body.

Scientifically reviewed by: Dr. Vanessa Pavey, ND, in August 2023. Written by: Mary Benton.

Three recently published studies have confirmed the importance of fish oil supplementation in heart disease patients with major depression.1-3

This is of great importance because one in four patients with cardiovascular disease (heart attacks, heart failure, angina, and others) also has depression—a double whammy that increases the risk of mortality.4

Studies show powerful associations between cardiovascular disease and depression:5-8

  • People with cardiovascular disease are more likely to have depression than the general population.
  • Those with depression are more likely to develop or have cardiovascular disease. They also die at a higher rate than the general population.
  • People with cardiovascular disease who are depressed have worse outcomes than heart patients who are not depressed.
  • The more severe the depression, the higher the risk of dying or having additional cardiovascular disease events.

While some researchers think that depression may only be a “marker” for those with more severe cardiovascular disease, the simple fact that depression occurs so much more often in heart patients suggests to most experts that there is a causal relationship.5

Three new studies offer clear evidence that omega-3 fatty acids in fish oil provide protection against the deadly combination of heart disease and depression.

Antidepressant Value of Fish Oil in Heart Disease



Depression and heart disease might seem like two completely different diseases, but they share one common underlying factor: inflammation.9-12

This connection helps explain why there is so much overlap between these two seemingly unrelated conditions. It also helps explain why omega-3s—which are well known for their powerful anti-inflammatory properties—are beneficial for both heart disease and depression.

Because heart disease can lead to depression, and depression to heart disease, it makes perfect sense to attack both conditions with an anti-inflammatory supplement.

The recently published studies highlight this important protocol.

In the first study, researchers from the Department of Psychiatry and Behavioral Neuroscience at the University of Cincinnati College of Medicine conducted a review that cites three decades of accumulating evidence demonstrating an undeniable link between omega-3 fatty acids, depression, and cardiovascular disease.

This review clearly found that depression arises in large part from dietary deficiencies in two specific omega-3 fatty acids: EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid).2 Higher consumption of EPA plus DHA was found to be associated with lower risks for both depressive symptoms and full-blown major depressive disorder.

In addition, this review showed that having lower levels of EPA and/or DHA not only significantly increases the risk for major depression, but also raises a person’s risk for both suicide and cardiovascular disease. Because suicide and cardiovascular disease are leading causes of premature death in patients with major depression, boosting EPA/DHA levels by supplementing with fish oil could be a key strategy for reducing mortality.2

Based on this evidence, the author ends the review with this plea:

“It’s time to translate all of the laboratory and clinical evidence about fish oil and its omega-3 content into routine clinical screening and treatment procedures, so that every heart patient has a better shot at long-term survival.”2

Making the Connection

The other two recently published studies are from a research group at the University of Toronto, where scientists have long been studying the relationships between diet and mental health.

The first article helps explain why fish oil is so helpful in combatting both heart disease and depression due to its impact on oxidative stress.1 Oxidative stress is common in patients with coronary artery disease, and scientists believe that it may contribute to depressive symptoms as well.13 As powerful anti-inflammatories, omega-3s are known to combat oxidative stress.

Based on these basic principles, the researchers evaluated whether this was the reason for omega-3’s ability to combat both heart disease and depression.

To determine this, they studied 79 patients with known coronary artery disease (a major risk for heart attacks) and rated the subjects using the standard Hamilton Depression Rating Scale. They also obtained baseline measures of oxidative stress in their blood. The subjects were then randomly assigned to receive either a placebo or 1.9 grams/day of omega-3 fats for 12 weeks.

The study showed that supplemented subjects who started out with high levels of oxidative stress had significant improvements in their depression scores. In addition, patients with the highest baseline levels of EPA/DHA had the greatest improvement in depressive symptoms. This indicates the importance of adding supplemental fish oil even to healthy diets that contain some omega-3s. No significant improvements were seen in placebo recipients, or in depressed patients with normal levels of chemical stress markers.

This study confirms that one of the reasons for omega-3’s benefits is because of its impact on oxidative stress. It also provides strong support for fish oil supplementation in people with cardiovascular disease who have high levels of oxidative stress and depressive symptoms.

The second of the Canadian studies was a simple evaluation of EPA plus DHA and their direct relationship to depression scores in patients with known coronary artery disease.3

Among the 76 subjects, those with lower ratios of total omega-3 (EPA/DHA) to omega-6 (arachidonic acid) had greater severity of depressive symptoms. Since omega-3s are anti-inflammatory, and omega-6s are generally pro-inflammatory, this study highlights, once again, not only the connection between inflammation and heart disease/depression, but the importance of combatting inflammation by increasing intake of omega-3 fatty acids (and decreasing dietary intake of omega-6 fats such as corn, safflower and cottonseed oils.)


Scientists are beginning to recognize a connection between two life-threatening conditions: heart disease and depression.

Studies show that having heart disease increases the risk of being depressed, while being depressed raises the risk for heart disease.

Both conditions are independently associated with premature death, and the combination of the two raises the risk of dying still more.

Since both heart disease and depression are closely associated with chronic, low-level inflammation, regular use of omega-3-rich fish oil, known to have potent anti-inflammatory properties, is especially beneficial for people with either, or both conditions.

New studies published in 2016/2017 confirm those findings, and demonstrate that, among those with either heart disease or depression (and certainly both) regular supplementation with fish oil can significantly improve symptoms.

If you have any questions on the scientific content of this article, please call a Life Extension® Wellness Specialist at 1-866-864-3027.


  1. Mazereeuw G, Herrmann N, Andreazza AC, et al. Oxidative stress predicts depressive symptom changes with omega-3 fatty acid treatment in coronary artery disease patients. Brain Behav Immun. 2017;60:136-41.
  2. McNamara RK. Role of Omega-3 Fatty Acids in the Etiology, Treatment, and Prevention of Depression: Current Status and Future Directions. J Nutr Intermed Metab. 2016;5:96-106.
  3. Mazereeuw G, Herrmann N, Ma DW, et al. Omega-3/omega-6 fatty acid ratios in different phospholipid classes and depressive symptoms in coronary artery disease patients. Brain Behav Immun. 2016;53:54-8.
  4. Bradley SM, Rumsfeld JS. Depression and cardiovascular disease. Trends Cardiovasc Med. 2015;25(7):614-22.
  5. Hare DL, Toukhsati SR, Johansson P, et al. Depression and cardiovascular disease: a clinical review. Eur Heart J. 2014;35(21):1365-72.
  6. Conklin SM, Harris JI, Manuck SB, et al. Serum omega-3 fatty acids are associated with variation in mood, personality and behavior in hypercholesterolemic community volunteers. Psychiatry Res. 2007;152(1):1-10.
  7. Jiang W, Oken H, Fiuzat M, et al. Plasma omega-3 polyunsaturated fatty acids and survival in patients with chronic heart failure and major depressive disorder. J Cardiovasc Transl Res. 2012;5(1):92-9.
  8. Haberka M, Mizia-Stec K, Mizia M, et al. Effects of n-3 polyunsaturated fatty acids on depressive symptoms, anxiety and emotional state in patients with acute myocardial infarction. Pharmacol Rep. 2013;65(1):59-68.
  9. Grosso G, Galvano F, Marventano S, et al. Omega-3 fatty acids and depression: Scientific evidence and biological mechanisms. Oxidative Medicine and Cellular Longevity. 2014;2014:16.
  10. Grosso G, Pajak A, Marventano S, et al. Role of omega-3 fatty acids in the treatment of depressive disorders: A comprehensive meta-analysis of randomized clinical trials. PLoS ONE. 2014;9(5):e96905.
  11. Zulyniak MA, Roke K, Gerling C, et al. Fish oil regulates blood fatty acid composition and oxylipin levels in healthy humans: A comparison of young and older men. Mol Nutr Food Res. 2016;60(3):631-41.
  12. Su KP, Lai HC, Yang HT, et al. Omega-3 fatty acids in the prevention of interferon-alpha-induced depression: results from a randomized, controlled trial. Biol Psychiatry. 2014;76(7):559-66.
  13. Chauvet-Gelinier JC, Trojak B, Verges-Patois B, et al. Review on depression and coronary heart disease. Arch Cardiovasc Dis. 2013;106(2):103-10.