Fish oil has long been promoted as a heart-healthy supplement, but new research from the University of Helsinki shows that its benefits may depend on individual metabolism.
The study, published in JCI Insight, examined how high doses of eicosapentaenoic acid (EPA), an omega-3 fatty acid found in fish oil, affect blood lipids and metabolism in 38 healthy adults. While EPA is known to reduce cardiovascular risk in people with high cholesterol or heart disease, much less is known about how it influences healthy individuals.
Researchers found that EPA significantly changed participants’ blood lipids, but not in the same way for everyone.
“The samples taken during supplementation clearly show the effect of EPA on all participants. Having said that, all samples were different among the group. In other words, each individual has a unique lipoprotein lipidome in their circulation, a ‘lipid fingerprint,’ if you will, that persisted despite EPA supplementation,” said Professor Katariina Öörni, one of the study’s lead authors.
The results showed that EPA was well absorbed, its concentration in blood multiplied during supplementation, but levels dropped rapidly once the participants stopped taking it. The strongest effects occurred in those with the lowest baseline EPA levels.
In addition to altering lipid composition, EPA improved participants’ blood lipid profiles and reduced the ability of lipoproteins to stick to arterial walls, a process that can lead to atherosclerosis. Still, the researchers caution that the study was short-term, and its long-term effects remain unknown.
“The findings highlight the importance of metabolism in the prevention of cardiovascular diseases. EPA’s effects varied more between individuals than we expected. We also demonstrated that these effects dissipate quickly, which is good to know in case EPA were to have adverse effects,” said doctoral researcher Lauri Äikäs.
Next, the team plans to study how EPA supplementation affects immune cells and inflammation-reducing lipid mediators. As Öörni noted, “It’s interesting to see how, for instance, dietary changes affect lipoprotein quality, or the individual lipid fingerprint.”
This research was supported by the Jenny and Antti Wihuri Foundation, the Research Council of Finland, the Sigrid Jusélius Foundation, the Finnish Foundation for Cardiovascular Research, the Emil Aaltonen Foundation, the Ida Montin Foundation, the Novo Nordisk Foundation, the Finnish Cultural Foundation, and the Jane and Aatos Erkko Foundation.