Effects of fish oil supplements vary, potentially reducing cardiovascular disease risk in healthy people as well

A recently completed study indicates that the positive effects of a fatty acid called eicosapentaenoic acid vary significantly between individuals. The study emphasizes the importance of metabolism in the prevention of cardiovascular diseases. It is published in the journal JCI Insight.

Finnish researchers investigated how eicosapentaenoic acid (EPA), an omega-3 fatty acid obtained from fish oil, affects healthy people’s blood lipid levels and metabolism.

EPA is known to reduce cardiovascular disease in individuals with elevated blood lipid levels or heart diseases. However, information on EPA’s effects on healthy people has been scarce, as has that on EPA accumulation in lipoproteins, which carry lipids (fatty molecules) in circulation.

In the study, 38 participants were given exceptionally high doses of EPA supplements, with samples collected before, during and after the supplementation. The findings demonstrate great individual variation in EPA’s effects.

“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,” says Professor Katariina Öörni, one of the two lead authors of the article, from the Faculty of Biological and Environmental Sciences, University of Helsinki, and the Wihuri Research Institute.

EPA effectively absorbed, but blood levels fall rapidly

The study also demonstrated that EPA is effectively absorbed, multiplying its concentration in the blood. However, the levels fall rapidly after supplementation ends. The strongest responses were seen in participants with low baseline EPA levels.

In addition, EPA improves the blood lipid profile and reduces lipoprotein attachment to components of the arterial walls. This reduction is important, as it is precisely such accumulation that leads to atherosclerosis.

Because of the short-term nature of the study, long-term effects remain unknown. The results nevertheless demonstrate how EPA modifies blood lipid composition and the risk mechanisms associated with atherosclerosis also in healthy individuals.

“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,” summarizes Doctoral Researcher Lauri Äikäs.

Next, the researchers will conduct cellular tests to determine how EPA supplementation affects the functioning of inflammatory cells and especially the amount of lipid mediators that suppress inflammation.

“It’s interesting to see how, for instance, dietary changes affect lipoprotein quality, or the individual lipid fingerprint,” Öörni muses.