A randomized clinical trial to determine the efficacy of manufacturers' recommended doses of omega-3 fatty acids from different sources in facilitating cardiovascular disease risk reduction

Abstract (provisional)


Omega-3 fatty acids confer beneficial health effects, but North Americans are lacking in their dietary omega-3-rich intake. Supplementation is an alternative to consumption of fish; however, not all omega-3 products are created equal. The trial objective was to compare the increases in blood levels of omega-3 fatty acids after consumption of four different omega-3 supplements, and to assess potential changes in cardiovascular disease risk following supplementation.


This was an open-label, randomized, cross-over study involving thirty-five healthy subjects. Supplements and daily doses (as recommended on product labels) were:Concentrated Triglyceride (rTG) fish oil: EPA of 650 mg, DHA of 450 mg

Ethyl Ester (EE) fish oil: EPA of 756 mg, DHA of 228 mg

Phospholipid (PL) krill oil: EPA of 150 mg, DHA of 90 mg

Triglyceride (TG) salmon oil: EPA of 180 mg, DHA of 220 mg.

Subjects were randomly assigned to consume one of four products, in random order, for a 28-day period, followed by a 4-week washout period. Subsequent testing of the remaining three products, followed by 4-week washout periods, continued until each subject had consumed each of the products. Blood samples before and after supplementation were quantified for fatty acid analysis using gas chromatography, and statistically analysed using ANOVA for repeated measures.


At the prescribed dosage, the statistical ranking of the four products in terms of increase in whole blood omega-3 fatty acid levels was concentrated rTG fish oil > EE fish oil > triglyceride TG salmon oil > PL krill oil. Whole blood EPA percentage increase in subjects consuming concentrated rTG fish oil was more than four times that of krill and salmon oil. Risk reduction in several elements of cardiovascular disease was achieved to a greater extent by the concentrated rTG fish oil than by any other supplement. Krill oil and (unconcentrated) triglyceride oil were relatively unsuccessful in this aspect of the study.


For the general population, the form and dose of omega-3 supplements may be immaterial. However, given these results, the form and dose may be important for those interested in reducing their risk of cardiovascular disease.

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Alex’s Notes: Not everyone eats fatty fish, but it seems that everyone supplements with fish oil or some form of omega-3s. Of course, not all supplements providing EPA/DHA are created equal, and supplement manufactures consistently promote that the form of the omega-3 affects its bioavailability, usually with a bias towards their product. This isn’t inaccurate, since all they must do is cherry pick a study that supports their claim, and countless contradicting studies exist. That’s what I like about the study at hand. It aimed to compare the effectiveness of different omega-3 supplements after a month of usage. All the supplements were tested for purity before and at the end of the study, and they were as follows:

Type of Omega-3 Supplement


Daily Supplied Dosage

EPA +DHA (mg)

Concentrated Triglyceride (rTG)

Nordic Naturals ProOmega®

650 + 450

Ethyl Ester (EE)

Minami MorEPA®

756 + 228

Phospholipid (PL)

Source Natural ArcticPure®

Krill Oil

150 + 90

Triglyceride (TG)

New Chapter Wholemega®

Salmon Oil

180 + 220

The participants were 32 middle-aged and overweight men and women. They all took one of the four supplements at the manufacturers recommended dose for a month, and changes in blood levels from baseline were measured. Overall, from best to worst the result was rTG, EE, TG, PL. This shouldn’t be a surprise because this order matches the total omega-3s consumed from each supplement. However, some interesting notes can be made by making comparisons between similar doses. For example, the EPA blood increase was similar for the rTG and EE, but the DHA increase in rTG was almost 4x as great as the EE group despite the rTG group only consuming 2x as much DHA. Similarly, the DHA intake of the EE and TG groups was nearly the same, yet the EE group had a 50% greater increase in blood DHA than the TG group. Then of course there were people whose blood levels decreased upon supplementation, likely reflecting individual genetic differences.

Given the considerable variability in the doses given to the participants, all the above is to be expected. The main take-away of this study is that dosage matters, and you needn’t waste your money on the overpriced krill oil or similar omega-3 supplements claiming superior bioavailability. You simply need to increase your intake.

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