Reasons for taking omega-3 for cardiovascular health were given a solid boost last month with the publication in Mayo Clinic Proceedings of a comprehensive study by O'Keefe of over 117,000 individuals looking at DHA blood levels and mortality [1].

The results were solid. The study showed a 21% reduced risk of cardiovascular death in those with high blood DHA (highest quintile) vs those with low blood DHA (lowest quintile). The quality of the report is high since DHA was actually measured in blood samples, rather than depending on food questionnaires, however, only DHA was measured due to the analytical technique not being suitable for EPA detection.

The last author is the well-known William Harris who published a similar finding from a meta-analysis of 17 studies in 2021 [2]. Harris now added on the new study to his 2021 publication to provide a meta-analysis of 18 studies with a total cohort of over 160,000 individuals with an average follow-up of 14 years. The data was emphatic with significant reductions in overall mortality, and CVD and cancer-related mortality.

An editorial was also published in the same journal issue supplying more context around the results [3]. Here, they weigh up the CVD hazard ratio measured in a Cochrane review of interventional studies [4] and conclude that the risk reduction is similar to that reported by the Mayo Clinic Proceedings article. The editorial notes the convergence of interventional and epidemiological data which they point out adds “plausibility” to the claim that omega-3 reduces mortality. The authors of the editorial concluded:  

The recent Mayo Clinic Proceedings study provided additional evidence on the implementation of omega-3 fatty acids in a healthy diet in the prevention of CVD and other disease outcomes; thus, the inclusion of DHA (and combined EPA and DHA) in disease prevention strategies can definitely still be recommended.

‍

References

1.            O'Keefe, E.L., et al., Circulating Docosahexaenoic Acid and Risk of All-Cause and Cause-Specific Mortality. Mayo Clin Proc, 2024. 99(4): p. 534-541.

2.            Harris, W.S., et al., Blood n-3 fatty acid levels and total and cause-specific mortality from 17 prospective studies. Nat Commun, 2021. 12(1): p. 2329.

3.            Laukkanen, J.A., A.A. Bernasconi, and C.J. Lavie, Bringing the Potential Benefits of Omega-3 to a Higher Level. Mayo Clin Proc, 2024. 99(4): p. 520-523.

4.            Abdelhamid, A.S., et al., Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev, 2018. 11(11): p. Cd003177.

‍