By: Dr. Rajon M. is a pharmacist who holds a PHD in Holistic Medicine
For more than half a decade, evidence on the health benefits of fish oil had been collated and well recognized by the scientific community. Fish oil is composed of several different fatty acids, some of which are essential for human growth and development. Human body can only synthesize certain essential fatty acids (EFA) but not those known as omega fatty acids. For this group of EFA, we have to obtain it from the diet, which mainly consists of fish such as salmon, sardine and mackerel. Fish oil is also an alternative for EFA.

fish freidWHAT’S IN THE FISH OIL? Eicosapentaenoic Acid

When talk of fish oil, you may have heard about the prominent fatty acid known as eicosapentaenoic acid (ERA). ‘Eicosi’ stands for ’20’ in Greek. The first double bond in the 20-carbon chain appears at the third carbon. This puts EPA in the omega-3 fatty acid class. The structure of omega-3 fatty acid is unique, your body cannot make rt but to source from the diet Eicosapentaenoic acid has long dominated the scientific and press headlines since the discovery of the low cardiovascular disease prevalence in the Eskimos. Why? Because Eskimos eat a lot of fish and fish are rich in omega-3 fatty acids.

Eicosapentaenoic acid has been associated with many cardiovascular and immune enhancing effects. It makes the Wood tess sticky and prevents Wood clots. It also appears to improve lipid profiles. It is the body’s raw material in the manufacture of super-hormones called eicosanoids. In fact, EPA was the focus of the 1982 Nobel Prize winning award for Medicine.

The nutritional supplement industry had been favouring EPA. Pharmacy and health shop shelves were packed with fish oil supplements, each claiming of its rich EPA content. Some manufacturers even called their fish oil product EPA!

Docosahexaenoic Acid

Another member belonging to the omega-3 fatty acid family is docosahexaenoic acid (DHA). Over the last few years, this omega-3 fatty acid, which is also contained in fish oil, has been getting much recognition. It could be the one of the most essential nutritional supplements of this millennium.

Recent studies show that, as a major constituent of brain and nerve lipids, DHA is vital to maintain the proper function of the central nervous system. It is selectively incorporated into the phospholipids in the eye retina and nerve synapses, making up as much as 60% of the lipids in the brain and nerve tissue. Significant amounts are also found in other membranes such as those in the cardiac tissue and sperm cells..

Early this year, a HarvardMedicalSchool study has linked high dose of fish oil (up to 12 grams per day) with significant anti-depressant effect. The Harvard researchers strongly attribute this effect to the DHA content of the fish oil.

DHA -the unique fatty acid Once you examine the structure of the DHA molecule, it is easy to appreciate why of all the fatty acids that exist in nature, DHA is truly unique. It is the longest and most complex of the long chain fatty acids. It has a 22-carbon backbone with 6 double bonds within the carbon chain. That is why DHA is highly flexible despite its length. This structure renders easy re-alignment. The double bonds make it functionally capable to conduct electrical messages throughout the body, unlike the saturated fatty acid structure (without double bond) found in most animal fats.

Pertaining to its functional characteristics, DHA is concentrated in parts of the body that need high electrical conductivity. Thus, DHA is found largely in the central nervous system -mostly in the brain. In fact, it is the most common structural fat of the human brain. The many double bonds also allow it to absorb free radicals. Therefore, high amounts of DHA in the brain can also delay free radical damage and the aging process.

In many conditions, both nutritional and medical, DHA may in the future be shown to be more important than EPA. It is now known that DHA can be easily retro- converted to EPA, hence providing both types of the very long chain omega-3 fatty acids according to the needs of the body. However, the conversion of EPA to DHA is limited in many conditions. It is somewhat less easy compared with the conversion of DHA to EPA as the body’s enzyme systems favour in reducing the number of carbon atoms in the chain rather than elongating it. Moreover, this process becomes less efficient as we age.

Sorting out the differences, these two fatty acids have rather major differences in the way and where they function in the body. Eicosapentaenoic acid is said to mainly benefit the cardiovascular systems. It also improves inflammatory problems like autoimmune disorders, asthma and arthritis. The potential of EPA to thin blood has led to the fear that it may predispose users to bleeding problems. However, this has never happened in real life at the doses that have been recommended.

Docosahexaenoic acid, on the other hand, is clearly linked to mental functioning as well as vision ability. It not only plays a vital role during pregnancy and infant development, but also during old age, in mental conditions, and in patients with peroxisomal disorders.

How much can one take? Recommendations have been so far focusing on the total omega-3 intake. However, more new research is now targeting on the DHA component in the fish oil. This is especially so since new technology is now available to allow cost effective commercial production of pure DHA from micro-algae. After all, the DHA found in fish is not made by the fish themselves. The fish merely concentrate the DHA that is produced by the micro- algae they consumed, of which comprise the base of the marine food chain. The current recommended DHA dose by the National Institute of Health of the United States is 660mg daily, while other researchers recommend 200 -400mg for adults and 100mg daily for children.

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