Krill oil contains more effective Omega-3 EPA and DHA than fish oil.

Omega-3s contained in krill are integrated into the membranes of red blood cells more readily than those contained in fish oil. In fact, the EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) of the tiny marine invertebrates that make up krill appear to have greater bioavailability than those in fish oil.

This was revealed in a study conducted in Canada by researchers at the Centre for Functional Foods and Nutraceuticals in Winnipeg . The research, published in the journal Lipids in Health Disease, is a further contribution to the recent debate on the positive effects of krill oil.

Omega-3 from krill and fish: differences in chemical form  

 Omega-3 EPA and DHA perform several important biological functions. One of these is to be part of the components of cell membranes and to give them the fluidity necessary for various activities of the cell.

The percentage of EPA and DHA out of the total fatty acids in red blood cell membranes is called the Omega-3 Index.

The value of this index is inversely proportional to the risk of cardiovascular problems.

Both fish oil and krill oil are rich in Omega-3. In the former food, however, EPA and DHA are found bound to triglycerides. In contrast, the Omega-3s contained in krill oil are found bound to phospholipids . Phospholipids, molecules consisting of a lipid region and one containing a phosphate group, are the main components of cell membranes. 

L'krill oil is most effective in increasing the Index of
Omega-3 

During the study, 24 healthy volunteers were recruited and followed a trial of three different phases, each of 4 weeks interspersed with a period of 8. The volunteers, randomly divided into three groups, took 6 capsules per day during the treatment. In the first phase, one group took krill oil, one took fish oil, and one took a placebo. After 4 weeks of treatment and an 8-week interval, each group received a different type of capsules for 28 days, and so on so that each person could follow the supplementation with the two types of oil and the placebo. For each volunteer before and after each phase, the content of Omega-3 in plasma and red blood cells was analyzed. The results showed, after each phase, an increase in both plasma and erythrocyte Omega-3 levels in the subjects who had received the supplements, compared with those who had ingested the placebo. The decrease in Omega-6 concentration in the supplemented volunteers was also evident. Specifically, in those who had received Krill oil, the increase in Omega-3 and decrease in Omega-6 was greater than in those who had ingested the other supplement The change in Omega-3 index after Krill oil consumption was 1.04%, and that following fish oil treatment was 0.47%. 

Probable ruolo of the phospholipid structure 

The results obtained show a greater efficacy of Krill supplementation than fish supplementation and thus a better protective effect against cardiovascular disease. This study therefore strengthens the hypothesis of the greater bioavailability of Omega-3 from Krill oil. Indeed, both Schuchardt, in 2011 and Maki, in 2009, showed that in plasma the concentration of Omega-3 was higher after Krill oil administration than after fish oil administration. The scientists hypothesize that due to the phospholipid structure, Krill Omega-3s may be more easily absorbed and integrated into cell membranes than those bound to triglycerides. However, more studies are needed to prove this thesis and clarify the mechanism.

 Sources: Ramprasath VR, Eyal I, Zchut S, Jones PJ. 'Enhanced increase of omega-3 index in healthy individuals with response to 4-week n-3 fatty acid supplementation from krill oil versus fish oil' Lipids Health Disease. 2013 Dec 5;12(1):178 Jan Philipp Schuchardt, Inga Schneider, Henrike Meyer, Juliane Neubronner,Clemens von Schacky and Andreas Hahn Incorporation of EPA and DHA into plasma phospholipids in response to different omega-3 fatty acid formulations - a comparative bioavailability study of fish oil vs. krill oil. Lipids in Health and Disease 2011, 10:145 Maki KC, Reeves MS, Farmer M, Griinari M, Berge K, Vik H, Hubacher R, Rains TM. Krill oil supplementation increases plasma concentrations of eicosapentaenoic and docosahexaenoic acids in overweight and obese men and women Nutr Res. 2009 Sep;29(9):609-15.