EPA is an omega-3 fatty acid, derived from fish oil, which cannot be produced by the body in sufficient amounts and has to be obtained through the diet or by supplementation.

Western diets are well supplied with omega-6 fatty acids from vegetable oils and other sources, which compete for the omega-3 fatty acids’ availability in the body. As a consequence, while many people have adequate supplies of omega-6, they can be deficient in omega-3. The most beneficial ratio of omega-6 to omega-3 fatty acids in blood may vary from 1:1 to 5:1, while for many this runs at 12:1 or even as high as 20:1.
Current dietary guidelines are to eat at least two portions of oily fish (mackerel, herring, salmon, fresh tuna) a week.
Vegetarian sources of omega-3 fatty acids are possible from algae sources on which fish also feed. Although, these omega-3 sources mainly provide DHA, but not the EPA that is necessary for concentration and emotional well-being.Cod liver oil supplements are a poor source of omega-3 fatty acids as they contain vitamin A, which can be toxic if taken at levels necessary to ensure a therapeutic dose of EPA.

Highly purified EPA (such as the pure ethyl-EPA that was used in this study) is essential for brain functioning, which explains its beneficial effect for concentration and mood disorders. Beside these benefits, EPA exerts anti-inflammatory effects throughout the body and contributes to good cardiovascular health.

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