Do fish oils cause arrythmia?

Fish oils are one of the most commonly taken supplements by smart professionals. But what if your fish oil is actually doing your more harm than good? Let’s dig into the science and use our brains.

Fish oils under fire - Are omega-3 fatty acid supplements dangerous?

HOLD ON TO YOUR SALMON BELLIES! We’ve got controversy about supplements and nutraceuticals again, with mainstream medicine trying to make natural health products look dangerous - because god forbid there could be dietary, lifestyle and nutraceutical and botanical interventions that might, when used appropriately and prescribed by a knowledgeable healthcare practitioner  be safe, effective and Oh right you can’t patent that shit.

If you’re taking any supplements, you probably know that omega-3 fatty acids, typically derived from fish oil, are one of the most basic, most important, most science-based and evidence-informed and likely beneficial nutraceuticals for your long-term healthspan.  

But wait! Sometimes science likes to screw with our heads.  A new study in the journal Circulation - A systematic review and meta-analysis, the strongest forms of evidence-based research we have in modern science, is reporting now that fish oils and omega-3 fatty acid supplementation is correlated with atrial fibrillation, an arrythmia that is related to blood clots in the heart, stroke, heart failure and other heart-related complications.  

Oh shit, sorry, fish oil is actually BAD for you, and now we SHOULDN’T take it as a supplement?

Now if you’re a self proclaimed biohacker, or if you know enough to be talking and researching about healthspan instead of longevity or if you just are looking for ways to be the best version of yourself and have your brain and body functioning at the peak of their capacity -and if you want to do that in an evidenced- andd science based, but integrative and holistic way, you should probably hit that subscribe button, because that’s my jam and I’m hear to share my 16 years of clinical experience in precision medicine and functional genetics, as a Coach, as Dad and as a Naturopathic doctor licensed here in Vancouver, British Columbia, Canada.

OK so Let’s just hold on a second.  If there’s one thing that I have learned in my 16 years of practice, it’s that Mainstream media doesn’t know how to interpret science.  And if there’s another thing I’ve learned is that peer reviewed journals still have bias and an agenda.  If you actually read the study and the results, instead of just reading the conclusions, sometimes you’ll find a different story than what is presented in the media.

In this case, the study, the meta-analysis research article that we’re all talking about was published a peer reviewed journal, Circulation, Vol 144, 25.  In total, the research article included over 81,000 patients across 7 different clinical trials, and average follow-up observation period was 5 years, which is really fantastic when it comes to dietary interventions, that we can track and follow-up on patients for that long.  And that’s how we can learn things like, perhaps, that fish oils might cause arrhythmia, and atrial fibrillation, specifically.

But to actually be evidence-informed, rather than evidence-based, means thinking with your brain, and applying clinical research data to an individual person, typically yourself.  So we need to be thinking - what is the likelihood that this science is actually relevant to me.  For instance, if you’re a 30 year old healthy adult, does the fact that this meta analysis included a population that was on average, 65 years old make you feel any differently about this fish oil debacle?  Out of the 7 studies included in the metaanalysis, 2 had an average age of patient at 62 or 63 years old, 2 more at 64 average age, and the rest from 65 to 75 as the average age.  And oh, by the way, atrial fibrillation and arrhythmias are much more common, as are hospitalizations, for people as we age, specifically over the age of 65 years old.

Now before this meta analysis, one criticism I had about some of the othe rstudies that have been held up in social media to vilify fish oils and omega-3s for atrial fibrillation and arrythmia were just shitty studies in terms of scientific metjod.  Which is why this meta analysis excluded them, and only focused on teh good science.  7 solid studies that met a rigorous qualifying standard.  And a lot of those other studies that were excluded, I wanted to mention, were studies that only saw the effect of atrial fibrillation associated with doses of fish oil over 4g per day - which is a lot of fish oil.  For most retail brands of fish oil that going to be at least 3, if not 6 or 10 capsules per day, or over 2 tsp of liquid fish oil daily.  And typical dosage for fish oil is in the neigihbourhood of 800-1000mg of combined EPA+DHA daily for most therapeutic targets.

But this meta-analysis, to be clear, did include several studies that used an intervention arm that used only about 1g per day of EPA+DHA combined.  Across the 7 studies they looked it, the incidence of atrial fibrillation was 1.3% per year, or a little more than 1 in 100 people who took fish oil in these studies, who were on average over 65 years old.  

HOWEVER 5 of these 7 studies - including the one study the authors clearly identify as the “main article”,  clearly indicated NO difference between the intervention arm (being given fish oil) compared to the control arm (we’ll call it a placebo, but in these studies the control arm varied from olive oil to mineral oil and others).  For those of you more familiar with statistics in medicine, the confidence interval at 95% crossed 1, which generally implies that there is no difference between the two arms of the studies.  The two studies that did have confidence intervals favoring increased hazard, or risk, ratio, were the two smallest studies, AND they were the two studies that used doses of fish oils OVER 4 g per day of combined EPA+DHA - that’s 2-4x more fish oil that I typically recommend for 95% of my patients!!!  To really pool these data together the dosage from the studies should ideally have been standardized.  The low n, or number of people in the two studies with very high dosing skewed the meta-analysis pooled results, and even stinks a bit of cherry picking studies try to make a point.  They stick out as two studies that are vastly and fundamentally different from the other studies.

Oh yeah, and I almost forgot to mention that almost all of these studies that were included in this meta-analysis were also being done between 2019-2021.  When we have been dealing with a global pandemic, are seeing unprecedented levels of perceived stress and anxiety (which increases the likelihood of atrial fibrillation), and have been in most countries in the world,  undergoing mass vaccination for COVID-19 - virus which, itself and its vaccines, have been linked with heart issues.

This is an example of how science, and evidence-based information, can be used to sway opinion due to people’s laziness to read, learn, interpret scientific data, and generally think with their brains when generalized to suggest that there is always a black and white answer of whether something is good or bad for us as a potential treatment.  It’s also frankly, in my personal opinion, an example of a really poorly written, or perhaps clearly biased conclusion to what is otherwise a good piece of scientific literature.

Does this meta-analysis raise my eyebrows about atrial fibrillation with high dose fish oil?  Yes.  especially for patients in their mid sixties and onward.   Does that science actually prove cause and effect here?  Nope.   and it’s Much less concerning for patients younger than that. 

And from the science that is out there, I’ll agree with caution or even contraindication of high dose fish oil above 4g per day of combined EPA+DHA in general, and I have consciously made that adjustment in my practice.  But at standard therapeutic doses in healthy, younger populations, fish oil remains a supplement that can be very important and fundamental to strategic, individualized and precision medicine diets. Especially when combined with functional genetics and comprehensive bloodwork to determine priority and leveraged opportunities for optimizing health.

As always, before you take any supplements or nutraceuticals, or medications for that matter, be sure to consult with your licensed and experienced healthcare practitioner, because even natural health products are not always safe for everyone to take, they can be dangerous, and need to be considered in your own individual context in combination with your other treatments, supplements or medications.

Bottom line.  A meta-analysis suggested a link between fish oil consumption and atrial fibrillation.  BUT The only studies that have shown this effect so far have been with dosing of fish oil at over 4g per day of combined EPA+DHA, and only in populations well into their mid-sixties.  Fish oil statistically has not been shown to cause atrial fibrillation or arrhythmia at doses below 4g per day, and is still one of the most and best studied health, medical and wellness treatments ever studied, including most drugs.

Got an opinion about this?  Come at me.  I’m happy to debate and I’d love to hear what you guys out there think.  In the meantime, keep being awesome.

dr. jason marr nd

I work with busy, urban professionals, entrepreneurs and new parents who want to be the most awesome versions of themselves. I leverage functional genetic testing and functional blood assessments to formulate precision medicine programs like RESILIENCELabs.

Ready for an instruction manual and blueprint for how your brain and body are built to function at their best? Let’s connect for a free health strategy session.

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