Heart Health
Do Omega-3s Cause Atrial Fibrillation?
A meta-analysis claims high-dose Omega-3 causes atrial fibrillation. Yet a critical examination of the data shows: for healthy people, Omega-3 remains essential for prevention.
Heart Health
A meta-analysis claims high-dose Omega-3 causes atrial fibrillation. Yet a critical examination of the data shows: for healthy people, Omega-3 remains essential for prevention.
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It's a shame that people are constantly "made uncertain" by information. Since edubily has existed, people have written us these exact two words in a single sentence. After all these years, it honestly gets to us a bit. Because: Why do people let themselves be "made uncertain" again and again? What's going on? Do they trust themselves so little? Their own head, their personal thinking and judgment? What's the issue? Why must one be made uncertain here and have their faith restored there (often by us)?
So a female follower sends us a newspaper article on Instagram about Omega-3 and atrial fibrillation. Referenced is a meta-analysis, based on seven studies, which concludes that Omega-3 supplementation of >1g is associated with a 50% increased incidence of atrial fibrillation (a cardiac arrhythmia). Omega-3 was already associated with atrial fibrillation even below that threshold, though the percentage was lower.
As someone who has been around for a long time... you "love" such meta-analyses. The massive datasets are processed in such a way that the authors themselves no longer know what they actually studied in the end. It's called epidemiology. It usually works particularly well when you want to clearly extract a really strong effect. For example, if you want to show that smokers have a significantly increased risk of lung cancer. Proven. No one would doubt that anymore.
But... >1g of Omega-3 is supposedly supposed to cause potentially deadly cardiac arrhythmias? A fatty acid that, just a few years ago, people wanted to show would prevent exactly that? A fatty acid that – according to mainstream medical opinion – basically does nothing in the body, is now supposed to be so potent that it kills people? That sounds completely bananas, doesn't it?
A look at the study shows that while they reviewed over 4,000 datasets, they only selected seven (larger) studies – and that the average age of the subjects was around 65 years. The Instagram follower, judging by her profile picture, is maybe half that age. And her friends, who had panicked at these results, probably too. Don't they know that you don't just get atrial fibrillation?
The list of risk factors is age-related and long: high blood pressure and heart valve disease, heart failure, coronary heart disease, cardiomyopathy and congenital heart disease. Lung-related risk factors include COPD, obesity and sleep apnea. Other risk factors include excessive alcohol consumption, tobacco smoking, diabetes mellitus and thyrotoxicosis. And then genetics play a role too. Preventive measures include: a healthy lifestyle, such as weight loss if overweight, more physical activity and less alcohol consumption. Aha.
Most people under 50 have virtually nothing to do with atrial fibrillation; the incidence is below 0.1%. If you're over 60, 4% get it. Looking at the mentioned frequencies in the study against the background of these numbers, it becomes apparent: Five of the seven studies show an incidence of atrial fibrillation in connection with Omega-3 of below 1%. Only two reach the age-typical 3–4%. Atrial fibrillation is thus observed less often in the studies than otherwise. From this numerical confusion, they then want to derive that Omega-3 promotes atrial fibrillation. How high the absolute number of added risk is when the hypothetical 50% is added on top of such low numbers, anyone can imagine for themselves.
The most important note remains: Here they didn't measure. So they know nothing about Omega-3 levels at baseline, nor during the intervention, nor about levels at the end of the intervention, and they don't even know anything about levels when people actually come to the hospital with atrial fibrillation. This was done ten years earlier in the "Cardiovascular Health Study" on 3,300 Americans, observed over a period of 14 years. Promptly the result was:
"In older adults, higher blood levels of long-chain n-3 PUFAs and docosahexaenoic acid were associated with a lower risk of atrial fibrillation (−30%)."
Topic actually settled, right? No, no. In the same year, yet another meta-analysis appeared with an even narrower, but essentially similar data selection, which "clarifies": Omega-3 causes atrial fibrillation. But only in people with elevated triglycerides and increased risk of cardiovascular disease. Mind you: Omega-3 is usually given at high doses because it significantly lowers triglycerides.
So what remains? As often: If you're healthy, you do prevention... or if you want to become healthy again, then Omega-3 is of course good and in adequate doses (1–2g per day) a decisive component. Of course. Part of any healthy lifestyle. Best if you get it from fish, because then you also get iodine, selenium, taurine and co. A small difference.
But if you're already (cardiac) sick... and want to stay that way, go to the doctor and have something prescribed, e.g. high-dose Omega-3 – along with other medications – yes then... you might end up in the hospital with atrial fibrillation. Then it's too late anyway. And exactly at this level are such results created, with 0.0 relevance for most of us.
We hope that reassures you. Everything about Omega-3 levels with a view to health can be found here.
