Eicosapentaenoic acid (EPA or sometimes misspelled as eicosapentanoic acid) is an omega-3 fatty acid that acts as a precursor for prostaglandin-3 (which inhibits platelet aggregation), thromboxane-3 and leukotriene-5 groups. Eicosapentaenoic acid and docosahexaenoic acid - dha - are precursors to potent bioactive mediators that possess both anti-inflammatory and protective properties. These mediators are coined resolvins, docosatrienes, and protectins as general classes. If you would like to buy a product with eicosapentaenoic acid and docosahexaenoic acid, see fish oils.

Where is Eicosapentaenoic acid found?
Eicosapentaenoic acid is found in fish oils of cod liver, herring, mackerel, salmon, menhaden, krill oil, and sardine. It is also found in human breast milk.

How Eicosapentaenoic acid is made
The main biological role of alpha-linolenic acid (18:3n-3) appears to be as a precursor for the synthesis of longer chain n-3 polyunsaturated fatty acids (PUFA). Increasing alphaLNA intake for a period of weeks to months results in an increase in the proportion of eicosapentaenoic acid (EPA; 20:5n-3) in plasma lipids, in erythrocytes, leukocytes, platelets and in breast milk but there is no increase in docosahexaenoic acid (22:6n-3), which may even decline in some pools at high alphaLNA intakes.

Potential benefit of eicosapentaenoic
The correction of a subtle nutritional deficiency that may reduce the risk of a future chronic disease is indeed a challenge. However, some specific examples in the past, such as the addition of folic acid to prevent neural tube defects and calcium and vitamin D to prevent osteoporosis, should provide some encouragement that some conditions can be prevented with the appropriate addition of a deficient compound. One of the most intriguing current and future impacts on public health may come from a greater intake of omega-3 fatty acids such as alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). The omega-3 fatty acids continue to accumulate research that suggests that may prevent a variety of diverse chronic diseases and potentially some acute clinical scenarios.

Eicosapentaenoic acid and depression
Depressive symptoms are commonly observed in elderly people, and nutritional factors such as eicosapentaenoic acid intake have been proposed as potential protective determinants of depressive disorders. Higher plasma eicosapentaenoic acid has been found to be associated with a lower severity of depression in elderly subjects, especially those taking antidepressants. Am J Clin Nutr 2008;87 1156-1162.

Testing for blood levels
Press release January 2010: VitalRemedyMD, a physician-established company, began marketing a blood testing kit to determine if you're getting enough Omega-3 in your diet or through fish oil supplements. The HS-Omega-3 Index is performed using a drop of blood from a simple fingerstick. It measures the two heart-healthy fats -- Docosahexaenoic (DHA) and Eicosapentaenoic (EPA) acids. William Harris, PhD, co-developer of the HS- Omega-3 Index comments, "Based on what we currently know there is no nutrient more important for decreasing risk of cardiovascular death--and more lacking--than omega-3."VitalRemedyMD, founded by Seth J. Baum, MD, FACC, FACPM, FAHA, FNLA, is also the developer of VitalOils1000 omega-3 fish oil that contains 1,000 mg of combined DHA and EPA in single soft gel.
   Comments: I don't see the need to test for omega-3 levels. Just improve your diet and take 2 to 4 fish oil capsules a day. There is too much testing done in this country without proof that such testing extends longevity.

Study in Eskimos
Associations of very high intakes of eicosapentaenoic and docosahexaenoic acids with biomarkers of chronic disease risk among Yup'ik Eskimos
American Journal of Clinical Nutrition, 2010. From the Division of Public Health Sciences Fred Hutchinson Cancer Research Center Seattle WA, the Center for Alaska Native Health Research Institute of Arctic Biology University of Alaska-Fairbanks Fairbanks AK.
Few studies have examined the associations of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) with biomarkers of chronic disease risk in populations with high intakes.We examined the associations of red blood cell (RBC) EPA and DHA, as percentages of total fatty acids, with biomarkers of chronic disease risk across a wide range of EPA and DHA intakes. In a cross-sectional study of 357 Yup'ik Eskimos, generalized additive models were used to plot covariate-adjusted associations of EPA and DHA with chronic disease biomarkers. Linear regression models were used to test for the statistical significance of these associations. Means (5th–95th percentiles) for RBC EPA and DHA were 2.8% and 6.8%, respectively. Associations of EPA and DHA were inverse and linear for triglycerides and positive and linear for HDL cholesterol and apolipoprotein A-I. Positive linear associations of DHA with LDL and total cholesterol were observed; for EPA, these associations were nonlinear and restricted to concentrations {approx}<5% of total fatty acids. Associations of EPA and DHA with C-reactive protein were inverse and nonlinear: for EPA, the association appeared stronger at concentrations {approx}>3% of total fatty acids; for DHA, it was observed only at concentrations {approx}>7% of total fatty acids. Increasing EPA and DHA intakes to amounts well above those consumed by the general US population may have strong beneficial effects on chronic disease risk.

Also occasionally spelled eicosapentanoic acid or eicosapentenoic acid

questions
Q. Is there also a vegetarian eicosapentaenoic acid EPA supplement available?
      A. At this time we are not aware of an EPA eicosapentaenoic acid vegetarian supplement by itself.