Well, here is a study from Stanford that elucidates the topic.
A research group at Stanford University published a 12 week double-blinded, parallel design, placebo controlled trial comparing the triglyceride lowering and omega-3 index-raising properties of 4g/day of equally proportioned EPA and DHA, provided in two different forms- a reconstituted triglyceride form (TG) or ethyl ester (EE) form (Oelrich 2011).
Subjects in the EE treatment group were found to have an 11% greater reduction in serum triglycerides and a 30% greater increase in omega-3 index compared to subjects in the TG group at the end of the 12-week study. This is important clinically because EFA incorporation into cellular phospholipids (i.e. RBC omega-3 index) closely correlates with the quantity of EFA's in the heart tissue and is inversely related to risk of fatal myocardial events (Lee 2008). The authors concluded, “There was no significant difference in the triglyceride-lowering effect of the formulations (EE vs TG) detected”.
This is the first long duration, double-blinded, placebo- controlled trial directly comparing the two different commercially available forms of fish oil (EE vs TG) using the two most widely accepted parameters in the assessment of omega-3 therapy: reduced serum triglycerides and improved omega-3 index, a quantification of EPA and DHA incorporated into tissues like RBCs. The data clearly shows no long term, “clinical advantage” of TG vs EE. Additionally the two largest and longest duration intervention trials published to date- the GISSI and JELIS trials which collectively involved more than 30,000 patients- used the ethyl ester (EE) as therapy in patients with CVD risk, reporting a 45% reduction in sudden cardiac death and 19% reduction in major adverse events respectively (Lee 2008).
