Eicosapentaenoic acid


Eicosapentaenoic acid is an omega-3 fatty acid. In physiological literature, it is given the name 20:5. It also has the trivial name timnodonic acid. In chemical structure, EPA is a carboxylic acid with a 20-carbon chain and five cis double bonds; the first double bond is located at the third carbon from the omega end.
EPA is a polyunsaturated fatty acid that acts as a precursor for prostaglandin-3, thromboxane-3, and leukotriene-5 eicosanoids. EPA is both a precursor and the hydrolytic breakdown product of eicosapentaenoyl ethanolamide. Although studies of fish oil supplements, which contain both docosahexaenoic acid and EPA, have failed to support claims of preventing heart attacks or strokes, a recent multi-year study of Vascepa, a prescription drug containing only EPA, was shown to reduce heart attack, stroke, and cardiovascular death by 25% relative to a placebo in those with statin-resistant hypertriglyceridemia.

Clinical significance

The US National Institute of Health's MedlinePlus lists medical conditions for which EPA is known or thought to be an effective treatment. Most of these involve its ability to lower inflammation.
Intake of large doses of long-chain omega-3 fatty acids as prescription drugs or dietary supplements are generally required to achieve significant lowering of triglycerides, and at those doses the effects can be significant.
It appears that both EPA and DHA lower triglycerides, however DHA appears to raise low-density lipoprotein and LDL-C values, while EPA does not.
EPA and DHA ethyl esters may be absorbed less well, thus work less well, when taken on an empty stomach or with a low-fat meal.
Omega-3 fatty acids, particularly EPA, have been studied for their effect on autistic spectrum disorder. Some have theorized that, since omega-3 fatty acid levels may be low in children with autism, supplementation might lead to an improvement in symptoms. While some uncontrolled studies have reported improvements, well-controlled studies have shown no statistically significant improvement in symptoms as a result of high-dose omega-3 supplementation.
In addition, studies have shown that omega-3 fatty acids may be useful for treating depression.