Eicosapentaenoic acid (EPA) is a long-chain omega-3 polyunsaturated fatty acid found in some fish and over-the-counter supplements. EPA is an essential component of the brain and plays a role in many cellular processes. There are mixed clinical findings with regards to brain health, likely due in part to different dosing and formulations. While clinical trials have not found a definitive cognitive benefit of EPA, people with higher circulating levels of EPA may be less likely to develop dementia or experience cognitive decline.
A number of observational studies and randomized controlled trials have assessed the effects of EPA on cognition and dementia. However, the results in terms of brain health are inconclusive as studies examine different doses and many include both EPA and another omega-3 polyunsaturated fatty acid, DHA, making it difficult to assess the role of each individually. Our search identified:
EPA is not as studied in terms of direct effect on brain health in comparison to its omega-3 fatty acid counterpart, DHA. The research into EPA is also complicated by the route of EPA supplementation (e.g., increased dietary intake or capsules), dose, and by the relative ratio of EPA to other omega-3 fatty acids in the formulation, such as DHA. There is some evidence that the ratio of DHA to EPA in a supplement can lead to different effects, but large studies have not yet been run to thoroughly explore this phenomenon. A randomized controlled trial in healthy adults found that participants given capsules higher in EPA had improvements in certain measures of cognition and memory [1]. A meta-analysis of observational studies found that higher serum EPA levels (reflective of higher dietary intake of EPA) were associated with lower incidence of cognitive decline and dementia [2]. However, a large meta-analysis of randomized controlled trials in healthy adults found little to no effect of omega-3 fatty acids, including EPA, on cognition [3].
EPA has been studied more extensively as a treatment for reducing cardiovascular risk. EPA is thought to improve serum lipid profiles, which may indirectly lower the risk of dementia [4].
The presence of an APOE4 allele may affect the response to EPA. However, the few studies that have examined the possible interaction between APOE4 and EPA have found conflicting results [5]. For more information on what the APOE4 gene allele means for your health, read our APOE4 information page.
A meta-analysis of randomized controlled trials of EPA in patients with Alzheimer's disease found no effect of EPA or other omega-3 fatty acid supplementation on cognitive function [6].
Long chain omega-3 fatty acids, including EPA, are well-studied and widely used as nutraceuticals in many countries. They are generally thought to be safe at doses less than 3 grams per day. A meta-analysis of randomized controlled trials found that gastrointestinal side effects are one of the most likely side effects of EPA [4].
It is important to note that the prescription formulations of EPA can be higher doses of 4 grams per day; these drugs carry greater potential benefits for some patient populations, but also greater potential risks such as atrial fibrillation and bleeding [7]. Some studies have also reported increased risk of prostate cancer and edema with higher intake or doses of EPA [7] [8].
NOTE: This is not a comprehensive safety evaluation or complete list of potentially harmful drug interactions. It is important to discuss safety issues with your physician before taking any new supplement or medication.
EPA is most commonly found in cold-water fatty fish, such as salmon, tuna, herring, and sardines. EPA supplements made from fish oil or algae are available, though the content and quality varies [9]. Highly purified formulations of EPA are available by prescription (e.g., Vascepa®). These drugs are rigorously tested and purified, but the higher doses have been associated with some increased risk of side effects such as atrial fibrillation.
The dose of EPA that is most beneficial for brain health is not known and may depend upon whether it is co-administered with DHA or not. Daily doses of more than 3 grams of omega-3 fatty acids including EPA may increase risk of side effects such as bleeding and atrial fibrillation.
Full scientific report (PDF) on Cognitive Vitality Reports
NIH Dietary Supplement Fact Sheet has information about omega-3 fatty acids and supplements
Check for drug-drug and drug-supplement interactions on Drugs.com