Fish oil: triglycerides or ethyl esters?

In natural fish oil, the polyunsaturated fatty acids EPA and DHA are found in the triglyceride form. However, to be able to produce highly concentrated supplements, these fatty acids are frequently converted into synthetic ethyl esters. Despite the fact that ethyl esters allow one to reach a higher fatty acid concentration per dose, there are some significant disadvantages to this approach.

The human body processes ethyl esters far less efficiently than triglycerides. This should not be surprising, considering that evolution has optimised us for the consumption of fish. As fish contains EPA and DHA as triglycerides, it is only natural that they are better absorbed than ethyl esters are. 

In addition, our body has to work harder to properly utilise ethyl esters and they are therefore far less effective. On top of that, some research has questioned their safety. There are therefore enough compelling reasons for Bonusan to stick with the natural form.

But why then does the idea persist in some that ethyl esters are at least as good, or maybe even better, than triglycerides? Large clinical trials are often carried out with ethyl esters. They are better available, lower priced and offer a higher concentration per dose, allowing participants in the trials to have to take no more than one capsule a day, which aids compliance.

It is easy to appreciate the said advantages for the researchers, yet this selection pressure unjustly tips the scales in favour of the unnatural form. Another major disadvantage is that the true health benefits of real fish oil remain in the dark.      

In short, as a result of the many disadvantages of ethyl esters, when using higher doses it is a better idea to advise an additional capsule with natural fish oil. And there is always an even better option available when one wants a superiorly absorbable, natural, highly concentrated supplement: fish oil emulsion.

Fatty acid emulsions are better absorbable then regular fatty acids and can be produced with natural triglycerides. Due to their better absorption, they can be used at a lower dose. An additional advantage of emulsions is that they are both water and fat soluble, so they can be mixed into foods. All in all this results in greater ease of use for a better compliance.    

Sources

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2. Raatz SK, Redmon JB, Wimmergren N, Donadio JV, Bibus DM, Enhanced absorption of n-3 fatty acids from emulsified compared with encapsulated fish oil, J Am Diet Assoc. 2009 Jun;109(6):1076-81.
3. El Boustani S, et al. Enteral absorption in man of eicosapentaenoic acid in different chemical forms. Lipids 22:711-14, 1987.
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5. Dyerberg J, et al. Bioavailability of n-3 fatty acids. In n-3 Fatty Acids: Prevention and Treatment in Vascular Disease, SD Kristensen, EB Schmidt, R DeCaterina and S Endres, eds. Bi and Gi Publishers, Verona—Springer Verlag, London pp. 217-26, 1995.