Does fish oil (omega-3 fatty acid) supplementation have therapeutic benefits, according to the latest research?

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Last updated: April 7, 2025View editorial policy

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From the Guidelines

Fish oil supplements are not recommended for ASCVD risk reduction due to lack of evidence on cardiovascular outcomes benefits and potential gastrointestinal side effects, whereas prescription omega-3 fatty acid products have been shown to be effective in reducing triglyceride levels and ASCVD risk in certain patient populations. The latest research, as outlined in the 2021 ACC expert consensus decision pathway 1, highlights the differences between nonprescription fish oil preparations and prescription omega-3 products. Unlike prescription omega-3 fatty acid products, nonprescription fish oil supplements are not FDA-approved to treat elevated triglyceride levels and have varying content and quality. Some key points to consider include:

  • Nonprescription fish oil products are not interchangeable with prescription omega-3 products 1
  • Prescription omega-3 fatty acid preparations, such as IPE, have been shown to be effective in reducing triglyceride levels and ASCVD risk in patients with elevated triglyceride levels and established cardiovascular disease or diabetes mellitus with additional risk factors 1
  • The most frequent adverse effects of prescription omega-3 fatty acid preparations include eructation, dyspepsia, and taste perversion 1
  • High doses of omega-3 fatty acids (1.8 to 4 g daily) have been associated with an increased risk of atrial fibrillation (AF) 1
  • Clinicians should evaluate the potential net benefit of prescription omega-3 fatty acids in patients at high risk of AF 1.

From the Research

Fish Oil Research

  • The latest research on fish oil suggests that it can be beneficial for reducing triglycerides and improving heart health 2, 3.
  • A 2019 study found that prescription omega-3 fatty acids (EPA+DHA or EPA-only) at a dose of 4 g/d can reduce triglycerides by ≥30% and decrease non-high-density lipoprotein cholesterol and apolipoprotein B 2.
  • Another study published in 2019 found that high DHA fish oil can have beneficial effects on heart and cardiovascular system, brain and visual function, inflammation and immune function, and growth/Body Mass Index 3.
  • However, a 2018 systematic review found that increasing omega-3 intake, including EPA and DHA, has little or no effect on all-cause mortality, cardiovascular mortality, and cardiovascular events 4.

Fish Oil Supplements

  • A 2015 study found that many commercial fish oil supplements do not contain the stated label amount of EPA and DHA, with over 70% of supplements tested not meeting the label claims 5.
  • This highlights the need for increased testing and regulation of fish oil supplements to ensure their quality and efficacy.

Health Benefits

  • The health benefits of fish oil are supported by several studies, including a 2004 review that found evidence for a benefit in coronary heart disease prevention 6.
  • However, the evidence for other health benefits, such as reducing the risk of depression disorders, is still unclear 3.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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