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Omega-3s & Your Risk of Atrial Fibrillation

Updated: Aug 9, 2021

In light of recent studies suggesting that omega-3 fatty acid intake may lead to an increased risk of developing atrial fibrillation, or AFib, you may be wondering if you should stop taking your omega-3 supplements.

In this blog, we break down exactly what the results from these studies mean and how you should adjust your omega-3 intake in response.

The studies:

In the past 2 years, 4 randomized clinical trials have contributed data on the risk of developing atrial fibrillation with omega-3 supplementation.

  • The STRENGTH trial: 13,078 high-risk participants with cardiovascular disease were randomly selected to receive a high dose, 4 grams/day, of omega-3 or a placebo. After around 2 years, there was no difference in cardiovascular health, but there was an increase in developing AFib in the omega-3 group. The group taking omega-3s was 2.2% more likely to develop AFib, compared to 1.3% in the placebo group.

  • The REDUCE-IT trial: 8,179 patients were randomized to receive a high dose, 4 grams/day, of omega-3 fatty aid or a placebo. After around 5 years, the researchers found that omega-3s resulted in a 25% reduction in composite cardiovascular end-point. However, there was also an increase in the risk of AFib in the omega-3 fatty acid group (5.3% vs 3.9% in the placebo group).

  • The OMEMI trial: 1,027 older participants who had a recent heart attack, were randomly selected to receive 1.8 grams/day of omega-3 or a placebo. After 2 years, there was no significant difference between the two groups in cardiovascular health. But 7.2% of the omega-3 group had developed AFib, compared to 4.0% of the placebo group.

  • The VITAL Rhythm Study: 12,542 patients were randomly selected to receive 840 mg/day of omega-3, and the other 12,557 received a placebo. After around 5 years, the incidence of AFib was 7.2% in the omega-3 group and 6.6% in the placebo group. It is important to note the results of this study were statistically INSIGNIFICANT- with no apparent increase in risk.

While these results may seem scary at first glance, there are several factors regarding these studies to consider before you drop your Omega-3 supplementation.

Participants of these studies were older, majority-white, and varying in risk factors.

  • The study with the greatest statistically significant difference between the omega-3 group and placebo group and an increase in the risk of developing AFib was in the OMEMI trial. All participants had recently suffered from a heart attack, which can lead to developing AFib. The other studies varied in risk factors, meaning the results should not be compared equally.

  • In the VITAL Rhythm trial, the average age of participants was 67 and roughly split equally between male and female. But in this study, only one in five participants was Black, with no mention of any other race. The risk of developing AFib varies throughout racial groups. Meaning these results should only be taken accurately for white people.

The omega-3 content varied throughout the studies.

  • The participants of the REDUCE-IT and STRENGTH trials were given VERY high dosages of omega-3, at 4 grams/day. The FDA has previously warned against doses of omega-3 that exceed 3 grams/day. High omega-3 supplementation has already been linked to blood-thinning and excessive bleeding.

  • The studies also demonstrate that as omega-3 dosage increases, as does the risk of AFib. The VITAL Rhythm and OMEMI studies, in which participants received what is considered to be a safe amount of omega-3 supplementation, had statistically insignificant results. It was only in the REDUCE-IT and STRENGTH trials, in which participants took over the recommended amount of Omega-3, that significant results were gleaned. Throughout the studies, the risk of AFib increased with omega-3 content.

The participants were not given omega-6 supplementation to offset omega-3.

  • Omega-6 and omega-3 are essentially opposites- omega-6 is pro-inflammatory, while omega-3 is anti-inflammatory. Our body is evolutionarily equipped to handle a 1:1 ratio of omega-6 and omega-3. Participants of the studies were given high amounts of omega-3s without the proper omega-6 supplementation. Inflammation is an essential part of survival- it helps protect your body against injury and infection.

Participants were not administered “clean” omega-3s.

  • The studies used different types of omega-3 supplements, but also did not state that proper care or guidance was given to prevent the oxidation of the omega-3 supplements. The chemical structure of omega-3 makes them highly prone to oxidization, when omega-3s oxidize, the chemical structure changes and the molecules break down into lipid peroxides- which give off the smell and taste of spoiled fish.

  • The health effects of consuming oxidized fish oil supplements are not yet known. However, in animal studies, consuming rancid oil has been linked to organ damage. Further research performed on fatty acids, found that when they are oxidized, they have a pro-inflammatory effect and may increase your risk of Alzheimer’s disease.

  • Click here to read our blog about preventing omega-3 oxidation.

Why you should wait to stop taking your omega-3s:

It is very critical to emphasize again that the only statistically significant results were found when participants were given a VERY HIGH omega-3 supplementation. When participants were given the normal amount, the results were not statistically significant, deeming omega-3 to have no link to AFib.

Further, the health benefits of supplementing with omega-3 intake are immense. These benefits of omega-3 include:

However, if you are nervous about continuing your omega-3 supplementation, there are certain foods you can increase consumption of in order to raise your omega-3 levels. These foods include:

  • Animal meat- Meat is among the best sources of omega-3 fatty acids. But, it is important to note that omega-3 levels are higher in grass-fed med. This is due to the diet of many unpasteurized animals, they are fed grain-based feed that contains soy and corn which are high in omega-6. Leaner cuts of meat will also include fewer omega-6s.

  • Pastured eggs- Similar to animal meat, chickens who were not pasture-raised will produce eggs with fewer omega-3s. Look for pasture-raised chickens when purchasing eggs. These are best found at your local farmer's market.

  • Seafood- Seafood is the best way to increase your omega-3 intake. It is recommended to eat seafood every other day to keep your omega levels balanced. Seafood highest in Omega3's are the SMASH fish: sardines, mackerel, anchovies, salmon, and herring. These are also the fish lowest in mercury.

In conclusion, yes the results of these studies seem scary. But, when looking deeper, the results do not reflect the daily omega-3 intake of most Americans, even those who supplement with omega-3 daily.

It is essential for your long-term health that you have appropriate omega-3 levels, but it is also essential that you get fresh omega-3s. If you want to take a supplement, we recommend the supplements below:

The Johnson Center for Health services patients in-person in our Blacksburg and Virginia Beach / Norfolk locations. We also offer telemedicine for residents of Virginia and North Carolina!


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