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Heart Health and Fish Oil: What’s the deal?

About the Author: Rohit Jayakar MD specializes in non-surgical Sports Medicine (Physical Medicine & Rehabilitation). He treats a variety of musculoskeletal injuries, neurological injuries, and pain conditions.

Responsible for 16% of deaths worldwide, heart disease is the number one killer on a global scale. What’s more, deaths attributed to cardiovascular disease have only increased over the last two decades, rising to 8.9 million deaths globally in 2019.1 

In the United States, one in every four deaths is caused by heart disease, and someone has a heart attack every 40 seconds.2 The national costs associated with heart disease are exorbitant,  exceeding 200 billion dollars each year.3

Heart disease comes in many forms, including coronary artery disease, heart rhythm disorders, structural heart disease, and heart failure. Coronary artery disease, the buildup of plaque in the heart’s arteries, is the most common form of heart disease, as well as the leading cause of heart attacks. 

Fortunately, coronary artery disease is preventable. Lifestyle changes including diet and exercise modifications can lead to a major decrease in heart attack risk, as well as other diseases like strokes. Moreover, medications are important to help manage underlying medical conditions that may increase the chance of experiencing a heart attack. 

In addition to traditional medication and lifestyle changes, there have been a wide range of conflicting messages regarding the benefits of fish oil supplementation to improve heart health. In fact, this topic has become so controversial that the Food and Drug Administration (FDA), who usually does not regulate or comment on supplements, has had to take a position on certain claims that have been made by supplement vendors. 

So, what are these supplements? Can they help with heart disease? Who should (and who should not) take them? 

In order to understand if supplementation is right for you, it is important to understand how fish oil supplements affect the risk factors leading to development of heart disease, including high blood pressure and high cholesterol. 

What is fish oil?

Fish oil is the oil extracted from fatty fish, whose benefits are attributed to its high concentration of Omega-3 Polyunsaturated Fatty Acids (PUFAs). 

There are 3 main types of omega-3s: ALA, DHA, and EPA. While ALA (alpha-linolenic acid) is found in other food sources like nuts and seeds, DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) are mainly found in oily fish. Moreover, DHA and EPA are thought to provide more benefits than ALA, as they offer anti-inflammatory properties which can aid in the treatment of health conditions like heart disease and certain cancers.

What Are The Benefits of Fish Oil for Heart Health?

Fish oil intake from natural food sources has been shown to be protective for the heart across  multiple studies, such as the DART study and Lyon Diet Heart Study. The Mediterranean diet is especially known to lower the risk of poor heart health; it consists of 1-2 servings of fish per week, along with fruits and vegetables, nuts, whole grains, and olive oil, while minimizing processed foods, dairy products, and red meat. 

Does fish oil supplementation come with these same benefits? Unfortunately, most claims on the benefits of supplementation are still heavily debated. In this next section, we’ll review the most common claims around fish oil supplementation for heart health, both for healthy adults and those with underlying diseases. 

Claim #1: “Fish Oil Supplementation Reduces Triglyceride Levels”

Triglycerides are a form of lipids (fats) found in the bloodstream that increase the risk of cardiovascular diseases. As of today, there is strong evidence that fish oil supplementation reduces triglyceride levels in those with elevated numbers. The REDUCE-IT trial, for instance, found significant benefits for triglyceride levels when researchers enrolled over 8,000 people with high triglyceride levels and randomized them to placebo or 2 grams of purified EPA twice a day. In 2019, the FDA even approved Vascepa, a purified form of EPA, for those with triglyceride levels greater than 150 mg/dl who are already on the highest tolerable doses of a traditional lipid-lowering statin. For those with normal triglyceride levels, however, more research is needed to assess the extent of lipid-lowering benefits that supplementation may provide.

Claim #2: “Fish Oil Supplementation Reduces Your Risk For Heart Attacks”

The REDUCE-IT trial also found that high-risk patients among the purified EPA group had less heart attacks and strokes. However, a subsequent study with a similar population, showed no difference in cardiac events when administering an EPA/DHA combination pill. 

There have been many other studies with conflicting results. In one older study, researchers followed 11,000 patients who had previously had a heart attack and randomized them to a EPA/DHA (850mg) pill versus placebo, and found that the group receiving the supplementation had a lower risk of future heart attacks and cardiac death. Nevertheless, attempts at replicating these findings have been difficult. For instance, the OMEGA study in 2010 and others subsequently had a similar protocol but found no differences in the two groups.

Due to the murkiness of the research around supplementation for coronary artery disease and heart attacks, the FDA has commented that “supportive but not conclusive research shows that consumption of EPA and DHA omega-3 fatty acids may reduce the risk of coronary heart disease” under certain circumstances. Therefore, despite all the research, we can only say that fish oil supplementation may or may not be helpful for preventing heart attacks in those with cardiac risk factors. 

Claim #3: “Fish Oil Supplement Reduces Blood Pressure”

There have been several studies on the effects of fish oil on blood pressure, many of which have produced varying results. Ultimately, none of the scientific literature has shown a strong improvement in blood pressure––in fact, due to erroneous health claims on supplement labels, the FDA issued an update in 2019 clarifying that the effects of EPA/DHA on blood pressure are “inconsistent and inconclusive.” At this point, fish oil supplementation is not recommended to treat or prevent high blood pressure.

Claim #4: “Fish Oil Supplementation Benefits The Heart In Healthy Adults”

Based on current studies, fish oil supplementation for healthy adults is generally not recommended. The VITAL trial in 2018, for example, studied the effects of a combined EPA/DHA supplement versus a placebo in over 25,000 people with no history of heart attacks or strokes, and found no improvement in cardiovascular health outcomes. Furthermore, a 2020 Cochrane review of many randomized trials concluded that fish oil supplements do not appear to significantly reduce the risk of cardiovascular events in healthy adults.

What Are The Risks of Fish Oil Supplementation?

In general, many supplements are not risk-free and should be approached with caution. It is always important to discuss any new supplement with your healthcare provider to ensure it is safe for you. 

At very high doses (more than 5g/day of EPA/DHA), fish oil supplements can increase bleeding risk. Therefore, those on blood thinners (e.g. warfarin) may experience a higher risk for hemorrhaging when taking fish oil supplements. Furthermore, supplementation can increase the chance of atrial fibrillation, a common heart arrhythmia. The European Society of Cardiology recently announced that caution should be taken with fish oil supplementation, as it carries an increased risk of atrial fibrillation in patients with cardiac risk factors. 

Supplementation can also come with mild side effects, such as gastrointestinal discomfort, nausea, and headaches. 

What Are Heart Organizations Saying?

The American Heart Association and World Health Organization recommend 1-2 servings of seafood per week to reduce heart disease. For those who already have heart disease, the AHA recommends 1g/day of EPA/DHA from oily fish, and states that supplements can also be considered for those with high cardiovascular risk who do not eat fish. In contrast, the organization does not recommend supplementation for those without risk factors. The Academy of Nutrition and Dietetics, as well as The National Lipid Association, recommends 2 or more servings of fatty fish per week. The U.S. Department of Agriculture recommends 8 oz per week of a variety of seafood.7

 See Table 1 from this article for a list of oily fish and their respective omega-3 content.

Beyond Supplementation: What Else Can I Do For My Heart?

Starting with a well-balanced Mediterranean diet and an exercise program can provide a large benefit that is more robust than fish oil supplementation. Furthermore, in those who already have heart disease, taking medication as prescribed is critical to control underlying health conditions (e.g. high blood pressure and high cholesterol) and to subsequently reduce the likelihood of developing heart disease. Traditional medications for heart disease and underlying risk factors include: Blood thinners (anticoagulants), antiplatelets, blood pressure medications, beta blockers, cholesterol lowering medications, antiarrhythmic medications, diuretics, and vasodilators. 

So, Is Supplementation Really Worth It?

Fish oil has many heart healthy benefits, but its effect is much stronger when ingested in real food rather than a pill. Oily fish, for instance, provides additional vitamins and antioxidants that are not found in supplements. Moreover, the government’s 2020-2025 Dietary Guidelines for Americans echoes the sentiment that nutritional needs should be met primarily through foods. 

That being said, fish oil supplementation can be beneficial for specific populations — namely those who have high triglycerides despite being on traditional medications, and possibly those who have had a prior heart attack and who are looking to reduce the likelihood of another episode. In addition, supplementation should not be used in isolation but rather alongside regular treatment. For those interested in fish oil supplements, a pure EPA or high EPA/DHA ratio is recommended, with a daily dose of one to four grams.

More importantly, remember that real change is made by managing underlying cardiovascular risk factors, a healthy diet, and a consistent exercise routine.


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