Omega-3 Fatty Acids and Heart Health

Omega-3 fatty acids, popularly known as "healthy fats," are known to benefit heart health. One key benefit of omega-3 supplementation is its ability to lower triglyceride levels. Specific types of omega-3s include DHA and EPA (found in seafood) and ALA (found in plants).

However, recent randomized clinical trials have raised concerns regarding potential off-target adverse effects from supplementation of n-3 polyunsaturated fatty acids (PUFA) on atrial fibrillation (AF) risk.

The OMEMI Trial

The OMEMI Trial by Peder L. Myhre and team suggests that supplementation of n-3 PUFA post-MI increases the risk of ‘micro-AF’ and AF, with increases in EPA seeming to be an important mediator of the treatment effect from n-3 PUFA on the risk of AF. The trial is published in the journal Clinical Nutrition.

Researchers aimed to assess the risk and potential mediators of AF and ‘micro-AF’ from n-3 PUFA in post-myocardial infarction (MI) patients. The OMEMI trial included 70–82-year-old patients with a recent MI who were randomized to 1.8 g/day of eicosapentaenoic-/docosahexaenoic acid (EPA/DHA) or placebo (corn oil) for two years. New-onset AF and ‘micro-AF’ were recorded by clinical detection and by screening with Zenicor thumb-ECG (adjudicated by blinded investigators). Serum EPA and DHA were measured at baseline and study end.

Key Findings of the Study

• At baseline, 759 of 1014 (75%) patients had no AF history. These patients were aged 75 ± 4 years and 71% were male.
• During follow-up, 43 patients developed new-onset AF (39 clinically-detected and 4 by thumb-ECG screening).
• In addition, 27 patients had episodes of micro-AF, yielding a total of 70 patients with new-onset AF or ‘micro-AF’.
• In the n-3 PUFA group, 46 (11.9%) had AF/’micro-AF’ (28 AF, 18 ‘micro-AF’) and in the placebo group, 24 (6.5%) had AF/micro-AF (15 AF, 9 micro-AF); HR 1.90 (95%CI 1.16–3.11), P = 0.011.
• Changes in serum EPA (but not DHA) mediated the effect from n-3 PUFA on AF risk, explaining 65% of the association.

Researchers concluded that “Supplementation of n-3 PUFA post-MI increases the risk of ‘micro-AF’ and AF, and increases in EPA seems to be an important mediator of the treatment effect from n-3 PUFA on the risk of AF.”

Reference: Peder L. Myhre a b, Trygve Berge b c 1, Are A. Kalstad b d, Sjur H et al; Omega-3 fatty acid supplements and risk of atrial fibrillation and ‘micro-atrial fibrillation’: A secondary analysis from the OMEMI trial, September 2023, DOI: https://doi.org/10.1016/j.clnu.2023.07.002.