Omega-3 and Atrial Fibrillation – How High Is the Risk, Really?

March 28, 2026

Omega-3 und Vorhofflimmern: Wie groß ist das Risiko?

March 28, 2026

“More than 1 gram of omega-3 per day increases the risk of atrial fibrillation” statements like this often make headlines. It sounds clear and alarming. This article puts the underlying data into context and shows why one point is crucial: the difference between relative and absolute risk.

But what do the studies actually show? The most robust evidence comes from large randomized trials and meta-analyses with more than 80,000 participants.

→ Better understand human studies

The key finding is: omega-3 fatty acids increase the relative risk of atrial fibrillation by about 20 to 25%. At first glance, this sounds like a significant effect. However, the absolute perspective is what matters most.

Relative vs absolute risk

The most important question is not whether a risk exists, but how large it actually is in everyday life.

In large studies, the risk of atrial fibrillation without omega-3 was about 3.3%, and with omega-3 about 4.0% over several years of follow-up.

This means: out of 1,000 people, about 33 develop atrial fibrillation without supplements and about 40 with supplements.

Or in other words: around 7 additional people per 1,000 develop the condition over roughly 5 years.

This corresponds to 1 additional case per about 140 individuals.

This number is critical for interpretation. It shows that while the effect is statistically clear, it remains small in absolute terms.

Healthy individuals vs high-risk patients

The most important factor for practical evaluation is the difference between healthy individuals and those with pre-existing conditions.

In healthy people without known cardiovascular disease, the baseline risk is low. Even if omega-3 increases relative risk, the absolute change remains small.

For an individual, this means: the risk is measurable, but in daily life usually not highly relevant.

The situation is different in people with existing heart disease, such as after a heart attack or with stents.

Here, the baseline risk is significantly higher. As a result, the absolute increase in risk is also higher.

In some studies, the difference exceeded 30 additional cases per 1,000 people. In this group, the effect can be clinically relevant.

The same relative increase in risk can therefore have very different consequences depending on the starting point.

Not all fish oil is the same

A key point in the public discussion is often overlooked.

Several studies showing increased risk used omega-3 in the so-called ethyl ester form (EE).

Fish oil in ethyl ester form (EE) is created through an industrial re-esterification process in which omega-3 fatty acids are separated from their natural glycerol backbone and bound to ethanol. This allows for high purity and concentration of EPA and DHA, but comes with a trade-off: the body must first enzymatically break this bond before absorption can occur. As a result, bioavailability is lower compared to the natural triglyceride form, as the structure differs from that of natural fish oil.

VITAQ Omega3 1100, in contrast, uses a fish oil concentrate in rTG form, which is structurally much closer to natural triglycerides found in fish and therefore better absorbed by the body.

It remains scientifically unclear whether results from studies using ethyl ester products can be directly transferred to highly purified rTG sources. In addition, many of these studies did not control for or report the oxidation level (TOTOX) of the products used, even though oxidized lipids may have independent pro-inflammatory effects.

Why dosage matters

The data show a clear dose-response relationship. At around 1 gram per day, the increase in risk is small. At higher doses, the risk rises more noticeably.

A recent review offers a possible explanation. Omega-3 may influence the nervous system, particularly the vagus nerve. Moderate activation may have stabilizing effects, while stronger activation under certain conditions may promote atrial fibrillation.

This explanation is biologically plausible, but not yet conclusively proven.

Are there also benefits?

A balanced evaluation must also consider potential positive effects. In large studies, high-dose omega-3 has been shown to reduce the risk of heart attack or stroke.

This means: a small increase in atrial fibrillation risk may be offset or even outweighed by other benefits.

This trade-off strongly depends on the individual situation.

What this means in everyday life

The statement that more than 1 gram of omega-3 increases the risk of atrial fibrillation is not wrong, but it is highly simplified.

The effect exists, but is small in absolute terms. The key factor is the absolute increase in risk, which remains low in healthy individuals but can become relevant in high-risk patients.

In addition, the form matters. Most data come from studies using high-dose ethyl ester products.

The key takeaway is therefore: omega-3 itself is not the issue, but rather the combination of high dose, specific form, and individual baseline risk.