Can Fish Oil Bring on an Irregular Heartbeat?

Fish oil provides the body with omega-3 fatty acids, which help the body in many areas including possible benefits to the heart. They do reduce cholesterol levels and lower the risk for suffering an ischemic stroke. It is unclear though, whether fish oil will help prevent heart palpitations or heart arrhythmias. The studies on this question offer mixed results.

What is Heart Arrhythmia?

Heart arrhythmia is a heartbeat pattern is slower or faster than it should be. This condition causes a range of symptoms from not any to cardiac death. Omega-3 fatty acids have an effect on the human heart in this area. The studies below explain in what way.


Researchers with the Portland VA Medical Center conducted a study involving 200 patients. These patients had either implantable defibrillators or cardioverters comparing the effects of placebo versus fish oil on said patients.

Heart Arrhythmia

The ones that took omega-fatty acids in a dose of 1.8 mg a day higher occurrence of two types of arrhythmias, VF (ventricular fibrillation) and VT (ventricular tachycardia) compared to the ones that took the placebo. The study went on for 24 months and the results were that 59 percent of the participants on the placebo and 65 percent of the participants on fish had one occurrence of either VF or VT. This study appeared in JAMA in June 2005.

An analysis of many studies some including animals and others including humans shows some results on the effects of n-3 fatty acids. These studies found that including these fatty acids into the diet changes enzymic activity and membrane composition, which could also change the workings of the ion channels. All these things relate to n-3 fatty acids having an anti-arrhythmic affect on the heart. Fish oil also can extend the ventricular effective refractory time, which measure the excitability of the myocardium.

A study in 2007 performed in Australia looked at how the phospholipids in the human myocardial membrane incorporates n-3 fatty acids DHA and EPA while the individual is taking supplements of fish oil and flax seed oil, which is rich in alpha linolenic acid. The participants that had normally low intakes of fish of less than 1 serving of fish a week with no fish oil supplementation and accepted for cardiopulmonary bypass, were divided randomly into 6 groups. This went on to include fish oil given in dosages of 6g of DHA +EPA each day for one week, 2 weeks or 3 weeks prior to surgery, no supplements, olive oil, or flaxseed oil.

The participants, who took fish oil, showed that the DHA and the EPA accumulated in the right atrium of the heart and it reached the maximum in about 30 days, but displaced the arachidonic acid. The flaxseed oil on the other hand increased the atrial EPA and not the DHA. The olive oil resulted in no change to speak of in atrial n-3 fatty acids. The result were that n-3 fatty acids taken in dietary supplements incorporate themselves into the myocardial phospholipids with high dosages of fish oil and push out the arachidonic acid.

Another study done on whether omega-3 fatty acids prevent atrial arrhythmias. The 40 participants had paroxysmal atrial tachyarrhythmia discovered during regular pacemaker controls. They took omega-3 fatty acids 1g/die. The results point to the omega-3 fatty acids having a huge effect on lowering the atrial arrhythmia-fibrillation in the participants. No negative side effects reported.

The studies show mixed results as to whether the fish oil causes irregular heartbeats. More studies performed may clear up the answer. This means that if you suffer from heart palpitations, rapid or uneven heartbeat, or any other heart issue, consult your doctor before taking fish oil.

Related Articles