Fish oil and omega-3 supplements have long been promoted for cardiovascular health, but recent research suggests they may increase atrial fibrillation risk in some individuals. Your individual health profile and any pre-existing conditions are strong determinants of whether fish oil supplements are appropriate.
Updated for 2026
Fish oil is a darling of biohackers and health influencers all over the world. However, unlike some new-fangled fads, you’ve probably known about fish oil since childhood. Of course, back then, we called it cod liver oil, a decidedly less sexy name for a potentially very beneficial compound.
Fish oil comes in many forms and is usually taken orally via a gel pill. There are liver oils, krill oils, and deep-sea fatty fish oils of all shapes and potencies available today. Ultimately, each advertises a combination of super-healthy omega fatty acids – the compounds that make fish so delicious and nutritious.
But Do They Prevent Afib?
The short answer is that, some studies, very interestingly, have shown that fish oil supplementation may increase the risk of developing Afib in individuals with elevated blood lipids.1
That being said, in a wider cardiovascular health discussion, the answer is more nuanced. Studies have shown the significant benefits of fish oils and fatty acids.2 The cardioprotective nature of these compounds is well-researched and can be helpful when purchased from a reputable manufacturer and used as indicated.
One study found that people who more closely followed a Mediterranean diet were actually less likely to develop atrial fibrillation.3 The research is by no means settled, and there’s plenty more to study, including whether there’s a difference between supplementation and natural sources.
What About Plant-Based Omega-3?
Plant-based omega-3s containing alpha-linolenic acid (ALA) have become more popular recently. These are usually derived from flaxseed, walnuts, or chia. However, it has been shown that most plant-based supplements are not as potent as their fish-based counterparts. Because humans convert only limited amounts of ALA into the biologically active omega-3 fatty acids EPA and DHA, their effects tend to be more modest than those of fish oil.4
Algae-based omega-3 supplements, which provide preformed DHA and EPA, seem to have similar potency and bioavailability to marine-derived supplements.5
Should I take Omega-3s?
With the hundreds, if not thousands, of fish oil and omega-3 products on the market, it may be tough to know which one is best because the FDA does not regulate supplements. It’s challenging to know that what you’re getting is pure and effective.
As such, do your due diligence, and if you are going to start a fish oil regimen, speak to your medical team, choose a supplement with a good reputation and, ideally, one that regularly tests their products for purity. Also, remember that oils do go rancid and are less effective over time. Be sure to understand the expiration date of any product that you buy.
If you begin to experience the symptoms of atrial fibrillation, speak to your medical team to understand if fish oil supplements may be a trigger.
- The best way to get the proper balance of omega-3s is from natural sources like:
- Deep sea fatty fish (salmon, mackerel, herring)
- Oysters
- Seeds and nuts (Walnuts, flaxseed, chia seed)
- Eggs
- Algae and seaweed
- Edamame and soybeans
- Hemp seeds
These are exceptionally healthy foods that are beneficial to the heart regardless of their omega-3 content. The variety of foods also add varying degrees of fiber as well as additional vitamins and minerals.
Clarifying a Myth:
Unfortunately, there are also several myths surrounding certain foods with omega-3s. Egg yolks and shellfish, for example, have been vilified in the past because of their high dietary cholesterol content. However, understand that dietary cholesterol does not translate into serum (blood) cholesterol – the kind we don’t want. As such, there’s no reason to avoid foods like shellfish and eggs. They can be cardioprotective in moderation and should be consumed if they are to your liking and you have no allergies.
As always, we encourage you to ask any questions about your diet at your next appointment. Dr. Tordini can work with your primary care physician and cardiologist to best understand your dietary needs for improved heart health. Always talk to a healthcare provider before introducing new supplements into your routine.
Related Resources
- Magnesium to Prevent Afib: Does It Work?
- Does Coffee Cause or Worsen Afib?
- Are Eggs Good or Bad for Afib & Your Heart?
- Zone 2 Training – An Exercise for Most Afib Patients
- Chocolate for Afib Prevention
- Dehydration and Afib & How Much Water Should You Drink?
- Are Weight Loss Drugs the Answer to Our Afib & Heart Health Issues?
- Cardio Versus Strength Training: What’s Better for Afib?
Dr. Tordini is a part of Florida Medical Clinic, Orlando Health.
REFERENCES
- Omega-3 supplementation linked with atrial fibrillation risk: a meta-analysis. (2021). Cardiovascular Journal of Africa, 32(3), 167. https://pmc.ncbi.nlm.nih.gov/articles/PMC8756005/.
- National Center for Complementary and Integrative Health. (2024, November). Omega-3 Supplements: What You Need To Know. NCCIH. https://www.nccih.nih.gov/health/omega3-supplements-what-you-need-to-know.
- Zhang, Q., Wu, S.-P., Liu, X., & Wang, Y.-L. (2024). Mediterranean diet and atrial fibrillation: a case-control study from China. Frontiers in Nutrition, 11. https://doi.org/10.3389/fnut.2024.1433274.
- Nettleton JA. Omega-3 fatty acids: comparison of plant and seafood sources in human nutrition. J Am Diet Assoc. 1991 Mar;91(3):331-7. PMID: 1825498. https://pubmed.ncbi.nlm.nih.gov/1825498/
- Santos, H. O., Price, J. C., & Bueno, A. A. (2020). Beyond Fish Oil Supplementation: The Effects of Alternative Plant Sources of Omega-3 Polyunsaturated Fatty Acids upon Lipid Indexes and Cardiometabolic Biomarkers-An Overview. Nutrients, 12(10), 3159. https://doi.org/10.3390/nu12103159.
