Eicosapentaenoic acid or EPA oil is an omega-3 fatty acid. It isn’t made in large supply by the body and needs to come from its natural sources such as oily fish. People who consume oily fish regularly most likely don’t need to supplement with EPA, but doctors may recommend EPA oil as a part of treatment for certain conditions. EPA supplements are almost always sold with DHA (docosahexaenoic acid), another omega-3 fatty acid, naturally present in many types of fish and also derived from certain forms of algae.
Studies on the benefits of EPA and DHA continue to reveal positive results. There is evidence that these fatty acids have beneficial effects on the heart, and when combined with other heart healthy behaviors, they may work, in part, to prevent heart disease. EPA and DHA have also been evaluated for efficacy in treating certain mental illnesses, and supplementation with both acids has been linked in studies to reducing depressive illness or depressive symptoms in bipolar disorder, when used in conjunction with standard medical treatment. Many of the studies involving EPA oil administration include co-administration of DHA, so it’s not always clear which acid is most effective or if the two work in combination, though it is theorized that EPA use could be better for depressive conditions.
For most healthy people, it’s fairly easy to find a combined DHA and EPA oil that would add some protection, and there are also a few foods that are supplemented with these fatty acids. Some problem exists in finding adequate EPA sources when people are vegetarians. For a long time, the recommended choice for vegetarians has been to use flaxseed oil, which contains alpha-linolenic acid (ALA). The body will synthesize some of this oil into EPA. Unfortunately, people have to take extremely high doses in order to get the same amount of EPA as they would get in fish sources of the oil.
Taking some DHA in algae form may be of use because the body will also convert some of it to EPA. There are a few vegetarian DHA and EPA oil supplements on the market, but they're not quite as effective as fish forms in providing the body with EPA. This could make a difference if EPA is being used to treat depression, where recommendation is to take about one to two grams of the acid daily.
Like all supplements, EPA oil isn’t for everyone. It may interact with some heart medications, especially anticoagulants and hypertension medicines. People who have diabetes or psoriasis should discuss with their physicians plans to supplement with DHA and EPA. Anyone who is taking this oil in addition to medication to treat a condition may need to have dosing changed over time. Usually, it isn’t necessary to change the diet to avoid natural EPA oil, unless sources of the oil endanger the body in some other way. Consuming fish with high toxin levels is not recommended, especially for pregnant women or young children.