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Atrial Fibrillation (AFib) and Omega 3s

  • 2 days ago
  • 3 min read


What it is:


Risk may emerge when:

  • There is already cardiac vulnerability

  • Dose is high (>1g/day)

  • EPA is disproportionately elevated to DHA


Omega-3 fatty acids, including EPA, DHA, and DPA, have traditionally been associated with cardiovascular benefit, but their relationship with atrial fibrillation (AFib) is more nuanced than previously understood. AFib is the most common sustained cardiac arrhythmia and involves disorganized electrical activity in the atria of the heart, which can reduce cardiac efficiency and increase stroke risk. Recent research has shown that, for some, there may be a U-shaped or threshold effect of AFib risk with supplements in which EPA is higher than DHA, or it’s EPA alone.


Earlier observational data linked higher fish intake with lower cardiovascular risk, leading to widespread use of omega-3 supplements: note the difference in choice between using whole-food fish versus supplements.




What the Science Says:


Some studies show a small increase in AFib incidence with higher dose omega-3 supplementation (≥1 g/day). Strongest in those with:

  • Existing cardiovascular disease

  • Older adults (>60 years)

  • Higher baseline AFib risk.

  • Trials using EPA-dominant or EPA-only formulations


Supplementation products often skew heavily toward EPA, especially with high-dose pharmaceutical products or lower-quality over-the-counter options.

  • Vascepa (https://fda.report/DailyMed/9c1a2828-1583-4414-ab22-a60480e8e508) - a purified form of the omega-3 fatty acid eicosapentaenoic acid (EPA), a prescription medication used to help lower elevated triglyceride levels and reduce cardiovascular risk when used alongside statin therapy.

    • Strongest evidence that high-dose EPA increases AFib risk. FDA website states, "WARNINGS AND PRECAUTIONS: Atrial Fibrillation/Flutter: VASCEPA was associated with an increased risk of atrial fibrillation or atrial flutter requiring hospitalization."


However, EPA-dominant supplements have shown benefits in other health areas, particularly at lower, dietary-range doses where the AFib risk is minimal, including mental health, triglyceride reduction, anti-inflammatory and antioxidant effects, and improved endothelial function. Also, in some people, high DHA supplements can raise LDL cholesterol levels, which is why Vascepa was viewed as beneficial.


Most fish naturally contain DHA levels similar to or higher than their EPA levels. But supplements often flip this, so most products have EPA > DHA.


When advising on Omega-3 supplements, it can be difficult to find products with a higher DHA-to-EPA ratio, so look for algae-based oils, cod liver oil, and specialized formulations. Some high-quality brands with DHA>EPA:

  1. Nordic Naturals - ProDHA Xtra: 960mg DHA, 410mg EPA, per 2 soft gels

  2. Nordic Naturals Algae Omega: 390mg DHA, 195mg EPA, 715 mg of total omega-3s, per 2 soft gels

  3. Carlson Labs Cod Liver Oil: 500mg DHA, 370mg EPA, 1,100mg of total omega-3s per tsp of oil.




Our Take:

Individuals with the highest plasma omega‐3 fatty acid levels were at the lowest risk for developing AFib. Whole food is best. Otherwise, a combination of moderate-level supplements (<1g/day) with whole foods.


Foods: NIH Table

  • Foods where DHA > EPA

    • Salmon, Herring, Mackerel, Seabass, Tuna

  • Foods where EPA >/= DHA

  • Oysters, Shrimp, Lobster


Please speak with your doctor or healthcare provider before starting any new supplements.



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