EPA (eicosapentaenoic acid)

An omega-3 fatty acid with an inflammation-dampening action – precursor of the E-series resolvins. The EPA/AA ratio is looked at in questions of inflammation.

What EPA does in the body

Eicosapentaenoic acid (EPA) is an omega-3 fatty acid with 20 carbon atoms and five double bonds – it has the same chain length as arachidonic acid and one more double bond. EPA sits in the phospholipids of cell membranes, particularly in blood cells and the vessel wall, and like arachidonic acid it is released by phospholipase A2 in response to a stimulus. The same cyclooxygenases and lipoxygenases convert it into prostaglandin E3, thromboxane A3 and leukotriene B5, which act considerably more weakly than their counterparts from arachidonic acid. EPA also gives rise to the E-series resolvins, which promote the clearing of cell debris and slow the influx of further immune cells. In the liver, EPA lowers the production and release of triglyceride-rich VLDL particles.

Low EPA – what happens in the body?

When little EPA is built in, the membranes contain proportionally more arachidonic acid. In response to a stimulus, the more potent prostaglandins, thromboxanes and leukotrienes then predominate, and fewer E-series resolvins are formed; in studies, inflammatory reactions subsided more slowly under these conditions. In the liver, part of the brake on VLDL production is missing, so triglycerides tend to be higher. Because the body makes EPA from ALA only to a limited extent, low values occur mainly with a low intake of long-chain omega-3 fatty acids, and also with disorders of fat absorption in the gut.

High EPA – what happens in the body?

A lot of EPA displaces arachidonic acid from the membranes and occupies the enzymes that would otherwise make its messengers. The signals for vessel narrowing, platelet clumping and pain perception are therefore milder, because thromboxane A3 and prostaglandin E3 act more weakly. In the liver less VLDL is produced, and triglycerides fall. Part of the EPA is lengthened into docosapentaenoic acid. Very high values usually reflect a high intake; with very large amounts of long-chain omega-3 fatty acids, studies have observed a slightly prolonged bleeding time.

The interpretation is given in your report.