Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are two oils found in fish oils, flaxseed and krill oils. These oils are good sources of omega-3 fatty acids. These omega-3 fatty acids must be obtained through diet or supplementation, since the body cannot manufacture them itself.
Fatty acids are made up of a carboxylic acid head with a chain of carbon atoms linked as a "tail." Omega-3 fatty acids have three carbon atoms on their tail, hence the "3" in omega-3. The term "fatty" refers to the fact that omega-3 fatty acids are naturally broken down from fats, like fish oil in the case of EPA and DHA. Omega-3 fatty acids are believed to be essential fatty acids as your body needs them to survive, yet the body does not make them. Thus, a daily supplement of EPA and DHA should be taken.
The omega-3 fatty acids contained within EPA and DHA provide several health benefits. Research points toward Omega-3 fatty acids possessing anti-inflammatory effects, meaning they help to reduce pain, swelling and tissue damage in the body. This may be beneficial in the treatment of rheumatoid arthritis or systemic lupus erythematosus (conditions that can cause joint swelling and pain).
EPA and DHA may also help form the brain and nervous system, maintain the fluidity of blood, and produce the structure of cell membranes.
Other benefits may include reducing high cholesterol levels to lowering blood pressure. Scientists are continually studying other potential benefits of DHA and EPA, ranging from reducing the effects of Alzheimer's disease to also reducing depression. Really, we should all be taking a good amount of Omega 3 fatty acids every day.