Fish Oil Supplements and Heart Health: What You Need to Know

Fatty acids known as Omega-3s are part of the "healthy fats" family and have been shown for years to improve heart health, reduce inflammation, possibly boost mental health and provide many other health benefits. Many people add fish oil supplements to their daily vitamin routine to help reap all those benefits. But a new study from the British Medical Journal reported that some patients who used fish oil supplements had a higher risk of certain heart conditions, such as atrial fibrillation. So what is the deal with fish oil supplements?

Is fish oil still good for my heart?

A large body of evidence suggests that fish oil is beneficial for the prevention of heart disease. The recent study from BMJ Medicine has raised some concerns about fish oil intake. The study used data from the UK Biobank and found that fish oil intake is linked to a 13 percent higher risk of atrial fibrillation in healthy people who do not have heart disease. The study also supported existing evidence that for those already diagnosed with heart disease, including atrial fibrillation, fish oil intake was linked to a lower risk of progressing to more severe heart disease. 

All of that said, the data from this study should be interpreted with caution.

First, the study relies on self-reported data, with no verification of the dosage of fish oil that participants took. The risk of atrial fibrillation with fish oil intake has only been observed in high doses. In higher doses of fish oil in certain forms, there is a link to reduced risk of more severe heart disease in people already diagnosed with heart disease. In low doses, such as one gram per day, fish oil intake has been shown to reduce heart attack risks without increasing the risk of atrial fibrillation, even in healthy people. Taking one gram of fish oil per day provides plenty of benefits without a proven, verified risk of developing heart conditions.

Second, as the study was observational and relied on one-time touchscreen questionnaire, there's no information on the brand, composition, or formula of the fish oil intake, in addition to no information on dosage. Fish oil supplements can vary widely, which could impact how much fish oil the participants were actually taking. 

FInally, the observational aspect of the study also failed to take into consideration that the people taking fish oil may have already been at risk for developing heart diseases including atrial fibrillation. These risks, which were not accounted for, could include a family history of heart disease or high cholesterol. 

Due to these limitations of the study, it is too early to decide that healthy people would only experience harm from fish oil supplementation. Based on high-quality, randomized trials of the past, the science still indicates that healthy people, particularly those at a higher risk of heart disease, would benefit from taking fish oil supplements in the proper dose. 

Why are there inconsistent data on fish oil supplements?

The primary issue with studying the effects of fish oil is that over-the-counter forms vary widely. As mentioned above, fish oil supplements can differ from one another in doses, composition, and sources of fish oil. Even prescription forms can have different formulations. This substantial variability is likely a major factor contributing to inconsistent findings in fish oil studies.

Factors such as the purity of the fish oil, the ratio of EPA to DHA (two types of omega-3 acids that our body needs), and the presence of other ingredients can all influence the outcomes. Additionally, differences in study populations, dosages, and duration of treatment can complicate the interpretation of results. 

Like other over-the-counter supplements, fish oil supplements are not held to the same stringent manufacturing and testing standards that prescription medications undergo. These lower standards can lead to significant variations in the concentration and stability of the active ingredients, potentially impacting their effectiveness. 

All of these variables likely account for inconsistent findings from studies on the benefits of fish oil supplements on heart health.

Who should take fish oil supplements?

While it's always preferable to get your vitamins and nutrients from whole foods as part of a balanced, heart-healthy diet, fish oil might be necessary for some people at high risk of heart disease, especially those who don't like fish or prefer a more plant-based diet. 

For people who have already been diagnosed with heart conditions, certain forms of fish oil can be beneficial. For people without diagnosed heart disease, fish oil supplements can still potentially be beneficial, especially for those who are at a higher risk of developing heart conditions. 

However, whether the benefits outweigh the risks will depend on the individual's specific risk factors. Whether certain doses and forms of fish oil supplements can provide benefits without causing harm still needs to be studied carefully with high-quality clinical trials beyond observational data. 

You should always talk with your doctor before adding new supplements to your regimen. Often, you don't actually need them and can save money by buying heart-healthy foods to get the vitamins and minerals naturally. If you have high triglycerides, diabetes, or heart disease, discuss with your doctor whether to take fish oil supplements and which forms might be right for you.

More research on fish oil is needed

Fish oil is not a one-size-fits-all solution. Personalized supplementation based on individual risk profiles will likely be the best approach. However, more research is needed. There are many other questions to consider: What are the mechanisms behind the beneficial effects of fish oil? What are the mechanisms behind high dose fish oil causing atrial fibrillation? Is there a clear dose threshold that causes atrial fibrillation? 

The Lipid and Prevention Program at the Lifespan Cardiovascular Institute is taking a lead in an NIH-funded study to answer some of these questions and more, especially around whether different components of fish oil have different effects in the cardiovascular system. The research conducted right here in Rhode Island could help shine some light on the benefits of fish oil for cardiovascular health and provide guidance for people around the world.

For more tips on how to live well and improve your cardiovascular health, visit the Lifespan Living blog.