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Providing perspectives on recent research into vitamins and nutritionals


Bioavailability of Omega-3 Fatty Acids Similar between Krill and Fish Oils

By Michael McBurney

Omega-3 fatty acids are known to benefit the heart. Research shows that n-3 fatty acids decrease risk of arrhythmias (abnormal heartbeats) which can lead to sudden death. In a world where most people do not eat the recommended two servings of fatty fish per week, supplementation is an important option to increase eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) intake.

EPA and DHA found in fish oil are largely in the form of triglycerides. Krill oil has its fatty acids in triglyceride, phospholipid and non-esterified fatty acid forms. These differences have been used to generate controversy regarding the bioavailability of krill versus fish and algal oils. Frankly, most comparisons haven’t been apples-to-apples.

Rather than depending upon single-dose kinetic studies with differing concentrations of each fatty acid, Yurko-Mauro and colleagues compared steady state plasma concentrations of n-3 fatty acids during 4 weeks of supplementation. Healthy adults (n=66) were enrolled into a 3 treatment, double-blind, randomized study receiving 1.3g/d of EPA+DHA daily for 28d in the form fish oil ethyl-ester, krill oil triglycerides, or krill oil capsules. Plasma and red blood cell (RBC) lipids were measured at baseline, and then 4, 8, 12, 48, 73, 336, and 672h post-first dose and at the end of 28d.

Mean plasma and RBC EPA+DHA concentrations within the first 72 hours following ingestion did not differ among the 3 treatments. Similarly, plasma and RBC EPA+DHA concentrations at 4 weeks were the same. The authors write “Our results show nearly identical bioavailability among the groups at early timepoints (<48h) of the plasma time course, illustrating no better bioavailability of one product versus another when equivalent concentrations of omega-3 fatty acids are administered.”  

Increasing your EPA and DHA intake can be beneficial. Focus on the numbers, the milligrams of EPA and DHA in a serving.  Most authorities and scientific bodies are recommending 250 to 500 mg EPA+DHA daily.

Main Citation

Yurko-Mauro K, Kralovec J, Bailey-Hall E, Smeberg V, Stark JG, Salem N. Similar eicosapentaenoic acid and docosahexaenoic acid plasma levels achieved with fish oil and krill oil in a randomized double-blind four-week bioavailability study. 2015 Lipids Health Dis doi: 10.1186/s12944-015-0109-z

Other Citations

Kris-Etherton PM, Harris WS, Appel LJ for the Nutrition Committee. AHA Scientific Statement: Fish  consumption, fish oil, omega-3 fatty acids, and cardiovascular disease. 2002 Circulation doi: 10.1161/01.CIR.0000038493.65177

Salem N, Kuratko CN. A reexamination of krill oil bioavailability studies. 2014 Lipids Health Dis doi: 10.1186/1476-5111X-13-137

Schuchardt JP, Schneider I, Meyer H, Neubronner J, von Schacky C, Hahn A. Incorporation of EPA and DHA into plasma phospholipids in response to different omega-3 fatty acids formulations – a comparative bioavailability of fish oil vs. krill oil. 2011 Lipids Health Dis doi: 10.1186/1476-511X-10-145