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Expansion of market access and production capabilities of numerous players in the omega-3 space has been motivated through greater consumer awareness and demand for Omega-3 in triglyceride form. Research has established improved absorption and bioavailability of triglyceride omega-3 when compared to the ethyl ester form. Hence, manufacturers are presented with an unmatched opportunity to address the growing trend evolving from choosing omega-3 triglycerides over ethyl esters, specifically in ultrapure and highly concentrated forms.

A major proportion of fish oil concentrates available on the market today constitute EPA and DHA concentrates of ethyl esters, with only a small percentage of them being natural triglycerides. The production process of ethyl ester concentrates offers the prospect of converting the fatty acids back to triglyceride forms with the use of food grade enzymes. Called glycerolysis, this process helps in removing the ethanol molecule and re-esterifying the EPA and DHA fatty acids to a glycerol backbone, which are commonly referred to as re-esterfied or concentrated triglycerides (rTGs). However, because cost factors come into play in the process of converting EE to TG by adding 30%-40% to the end cost of bulk oil, the only grounds offered for omitting the process of glycerolysis step can be cost reduction.

Being cheaper to produce than triglycerides, omega-3 fatty acid supplements in ethyl ester forms have become more widespread in the market, and the industry has also played a part in creating ethyl esters because of their being more malleable than triglycerides. Other factors include much higher boiling point and ease of use in processing for supplement distribution. Molecular distillation is a process principally used for removing industrial contaminants, such as heavy metals, dioxins, and PCBs, which are commonly found in the commodity fish oils used by most supplement makers, and concentrating the EPA and DHA omega-3 molecules. This process gives more importance to sterility in place of efficacy. Studies have established ethyl esters as being the least bioavailable forms of omega-3s when compared with triglyceride forms and/or whole fish. It is the factor of cost, therefore, that assumes importance after completion of purification through micro distillation, compelling the manufacturer to leave the omega-3 in its ethyl ester form, since the process of converting fish oil EEs back to TGs involves further outlay. As a result, bulk oil costs for TG concentrates typically range between 30%-40% more than EE concentrates.

Independently conducted studies in Germany and Denmark have established the efficacy of fish oil triglyceride omega-3s in bolstering the omega-3 index when compared to the ethyl ester form. Omega-3 index, which forms a quantification of the fatty acid status of a person, was found to increase at a faster and higher rate when triglyceride omega-3 was used in supplementations, in contrast to the ethyl ester form, which was revealed in the report of a study by researchers from Leibniz Universitat Hannover and Ludwig Maximilians University in Munich. The European Journal of Clinical Nutrition reports that a six-month supplementation with EPA and DHA in the triglyceride form helped in increasing omega-3 index by 197%, as against the 171% increase witnessed after being supplemented with EPA and DHA in their ethyl ester form.

Assessing the absorption and bioavailability of ethyl ester fish oils has also been the subject of several studies, with many of them measuring the amount of EPA and DHA in blood plasma after intake of EE or TG fatty acids. While a few studies were able to conclude that the absorption rate between the two oils is similar, there is an overall suggestion that absorption of TG fish oils is better than EE fish oils. Following are some of the salient outcomes of various studies conducted to compare absorption and bioavailability of EE and TG fish oils:

  • Natural TG fish oil resulting in 50 % more plasma EPA and DHA after absorption when compared to EE oils
  • TG forms of EPA and DHA shown to be 48% and 36% better absorbed compared to EE forms
  • Incorporation of EPA into plasma lipids found to be significantly smaller and taking longer when administered in EE form
  • Considerably higher plasma lipid concentrations of EPA and DHA with daily portions of salmon compared to three capsules of EE fish oil
  • In a rat animal model, DHA TG supplementation leading to higher plasma and erythrocyte DHA content compared to DHA EE supplementation, in addition to higher lymphatic recovery of EPA and DHA

In conclusion, it may be said that the natural TG form of fish oil supplements provide more and greater benefits in comparison to those in EE form, including safety in consumption, naturally occurring, providing better absorption and higher in stability. This further implies that if TG fish oil offers better absorption capabilities, it can also offer greater potential in reaching therapeutic ranges when compared to EE fish oil. Despite both being sources of omega-3 fatty acids, studies have shown TGs to be more beneficial, though further research is needed for a full assessment of potential toxicity. Though some countries, such as Australia, have prohibited the sale of EEs, other countries such as the US, Canada and the UK permit their sale with the requirement of additional labeling.