Understanding EPA And DHA

EPA and DHA are two omega 3 fatty acids that are found in fish and other marine life. EPA stands for eicosapentaenoic acid , and DHA stands for docosahexaenoic acid.

EPA and DHA are long chain fatty acids. Our bodies can make some EPA and DHA from Alpha-linolenic acid (ALA), which is an omega 3 fatty acid found in plant oils. However, to do so, we require an enzyme, delta-6-desaturase, that some people don't have - or don't have enough of.

There are other problems in converting ALA into EPA and DHA. Poor diet, alcohol, and other factors can reduce our capacity to make enough of these omega 3 fatty acids. Too much of the omega 6 fatty acids can also affect the conversion process, as the omega 6 linoleic acid (LA) needs the same enzymes.

Also, in the conversion process, EPA is made first, and DHA after that. Thus, we get even less DHA synthesized than EPA, as the conversion process is less efficient the further down the chain it happens.

What Do EPA And DHA Do?

Both EPA and DHA are used in our cell membranes to make them more fluid. Without some unsaturated fats in our cell membranes, the fat-containing molecules (phospholipids) become too tightly packed. DHA has a greater effect in this instance, as it has 6 double bonds to EPA's 5, but both help. Our cell membranes allow nutrients to pass in, and wastes to pass out, so the health of their structure is important.

As well as forming part of the structure of cells, EPA and DHA also affect the function of cells. The phospholipids, of which EPA and DHA become a part, are the means by which signal transduction takes place.

In our body, signal transduction refers to the way a signal from outside of the cell results in a change within the cell. Cellular signals can include hormones and neurotransmitters. These interact with specific receptors on the outside of a cell, and this interaction causes a change, or response, from what is called a 'second messenger'. The second messenger then triggers a change in some component within a cell. (Medterms)

EPA and DHA are also involved in the regulation of gene expression within cells.

EPA

EPA is also involved in the production of eicosanoids, which are hormone-like substances. Another fatty acid, the omega 6 arachadonic acid (AA), is also involved i the creation of eicosanoids. However, the eicosanoids that arachadonic acid produces can be a problem when there are too many. The eicosanoids made from EPA help keep the balance.

Eicosanoids produced by arachadonic acid are very metabolically active and increase:

• blood pressure
• inflammation
• the division of cells
• vasoconstriction
• blood clotting
• platelet aggregation

The last two are problems in heart disease, though it's important to note that they also have beneficial functions in our bodies - it's a matter of balance.

Eicosanoids made by EPA are less biologically active, and act as

• vasodilators
• anti-platelet aggregators

Specifically, EPA is a precursor to the eicosanoids known as series 3 prostaglandins and thromboxanes and series 5 leukotrienes. Arachadonic acid is a precursor to series 2 prostaglandins and thromboxanes and series 4 leukotrienes. (Medscape)

DHA is not directly converted into eicosanoids. However, it can be converted back into DHA, which can then be used to make eicosanoids.

As a vasodilator, EPA increases blood flow in our bodies. It is also beneficial for our immune system, having a modulatory effect. (CababstractsPlus)

DHA

DHA is an important component of our brain and eyes. It is fundamentally important in the neurological growth and development of children, and for their eyesight. But it is also important for adults of all ages too.

DHA is present in high levels in the rods and cones in our retina. It makes it easier for the ion channels in our brain to change shape and transmit electrical signals. (Nutraingredients) 

EPA and DHA have many important benefits for heart health, eye health, mood, the functioning of our brains, and a host of other functions. Whilst we can produce them in our bodies from a supply of the omega 3 fatty acid ALA, many people benefit from getting EPA and DHA directly. This is certainly true of people suffering from depression, mental illnesses, heart problems, inflammatory conditions like arthritis, crohns, ulcerative colitis, and asthma.