Do omega-3s help against heart rhythm disorders?
Omega-3 supplements do not help against heart rhythm disorders and at higher doses actually increase the risk of atrial fibrillation. Eating fish regularly appears to be a different story, but always discuss rhythm problems with your doctor first.
High doses of omega-3 supplements increase the risk of atrial fibrillation. Seven large randomised trials with more than 81,000 participants combined showed a 25% higher risk at doses above 1 gram per day. At doses higher than 1 gram per day that risk was even greater: 49% higher. This applied to pure EPA as well as to EPA combined with DHA. A lower dose, up to 1 gram per day, also raised the risk, albeit less markedly (12%). The risk therefore clearly increases with the dose.
For people who already have atrial fibrillation, omega-3 supplements do not help prevent relapse. Even after a previous cardiovascular event, no proven benefit has been demonstrated for this heart rhythm disorder.
Around cardiac surgery the picture is less clear. A large analysis of 19 randomised trials found that omega-3 supplementation just before and after the procedure reduced the risk of post-operative atrial fibrillation, particularly with oral intake. However, another analysis of 8 comparable trials found no significant effect. The two analyses therefore partly contradict each other.
Interestingly, the opposite applies to omega-3 from ordinary food. Higher blood levels of DHA and DPA, which build up through eating fish regularly, were associated with less atrial fibrillation in a large international study of nearly 55,000 participants. That association does not hold for dietary EPA, and it is not proof that eating fish is the cause, but the contrast with supplements is striking.
For ventricular rhythm disorders and sudden cardiac death, a different type of heart rhythm disorder, early studies and animal research suggested a protective effect via calcium channels in heart muscle cells. Later well-designed studies in humans have not confirmed that benefit. In cases of cardiac or rhythm problems, omega-3 supplements are not recommended for atrial fibrillation. If you have rhythm problems or are taking medication for them, discuss with your doctor whether omega-3 is safe for you.
The evidence on atrial fibrillation rests on several large randomised trials and multiple pooled analyses of those trials, with tens of thousands of participants in total. That is a solid basis for the elevated risk from supplements. The protective association with eating fish comes from a large international prospective study of nearly 55,000 people, but that cannot prove cause and effect. For post-operative atrial fibrillation, two analyses partly contradict each other, which makes the picture uncertain. For ventricular rhythm disorders the evidence is thin: early signals from laboratory and animal research have not been confirmed in humans.
Do omega-3 (fish oil) supplements benefit my heart?
Fish oil reliably lowers triglycerides and can slightly reduce the risk of a heart attack in people with existing heart disease or high risk, but it does not demonstrably lower the overall risk of death. Always discuss its use with your doctor if you have a condition or are on medication.
Does taking omega-3 help you stay healthy for longer?
Omega-3 reliably lowers blood fats, but the evidence that it helps you live longer or stay healthier is limited. If you already have heart disease, discuss with your doctor whether omega-3 is a worthwhile addition to your treatment.
Does reducing inflammation help your heart in the long term?
Targeted treatment to reduce inflammation, particularly with low-dose colchicine, measurably reduces the risk of serious heart events in people with coronary artery disease. Discuss with your cardiologist whether this is relevant for you, because not every drug works and there are safety considerations that require careful weighing.
Are calcium supplements bad for your heart?
Calcium supplements may be associated with an increased heart risk, but not all studies confirm this. It is best to get calcium from your diet, and discuss with your doctor whether a supplement is truly necessary for you.
Does omega-3 from fish oil help with chronic inflammation?
Omega-3 from fish oil lowers inflammation markers in the blood and has the strongest evidence in rheumatoid arthritis. The effect varies by condition and by person; if you have a joint condition, talking to your doctor is the logical first step.
What does an omega-3 deficiency do to your brain and mental resilience?
An omega-3 deficiency demonstrably harms the brain, especially during early development and in depression. If you have symptoms of low mood and are already taking antidepressants, omega-3 as an adjunct is the best-supported option; for Alzheimer's prevention, supplementation offers very little.